WATER POLLUTION CONTROL RESEARCH SERIES 16010 DON 02/72
Eutrophication Factors
in North Central Florida Lakes
U.S. ENVIRONMENTAL PROTECTION AGENCY
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Series describes the
results and progress in the control and abatement of pollution
in our Nation's vaters. They provide a central source of
information on the research, development and demonstration
activities in the Environmental Protection Agency, through
inhouse research and grants and contracts with Federal, State,
and local agencies, research institutions, and industrial
organizations.
Inquiries pertaining to Water Pollution Control Research
Reports should be directed to the Chief, Publications Branch
(Water), Research Information Division, R&M, Environmental
Protection Agency, Washington, B.C. 20460.
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EUTROPHICATION FACTORS
IN NORTH CENTRAL FLORIDA LAKES
By
H. D. Putnam, P. L. Brezonik, & E. E. Shannon
Environmental Engineering Department
University of Florida
Gainesville, Florida
for the
Office of Research and Monitoring
Environmental Protection Agency
Project # 16010 DON
February 1972
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Review Notice
This report has been reviewed by the Environmental Protection
Agency and approved for publication. Approval does not
signify that the contents necessarily reflect the views and
policies of the Environmental Protection Agency nor does
mention of trade names or commercial products constitute
endorsement or recommendation for use.
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20102 - Price $1 25
ii
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ABSTRACT
A small Florida lake has been receiving a regimen of nutrient
addition equivalent to 500 mg/m3-yr N and 43 tag/m3-yr P since 1967.
Data has been accumulated through 1969. The effect on the lacustrine
ecosystem of various biogenes includes production by primary producers,
species diversity of plankton and certain production estimates at the
secondary trophic level using natural populations of planktivorous fish.
Plankton production using isotopic carbon is ca. 58 grms/m2-yr; Species
diversity is slowly changing to a mixed chlorophycean and yellow-green.
Biomass of benthic green filamentous types has increased slightly. Nu-
trient addition has had little influence on zooplankton production.
Related studies on 53 other regional lakes have been done using
a multi-dimensional hybrid concept as defined by several trophic state
indicators. This trophic state index has provided a means for ranking
the lakes on an arbitrary scale. Cluster analysis utilizing pertinent
characteristics resulted in classification of other lakes.
Land use patterns and population characteristics were determined
photographically and N and P budgets estimated. Using multiple regres-
sion and canonical analysis, several significant relationships were
found between lake trophic state, lake basin, land use, and population
characteristics. In general, trophic state of lakes can be expressed
as a simple relationship incorporating K and P influx rates.
This report was submitted in fulfillment of Grant #16010DON
under the (partial) sponsorship of the Water Quality Office, Environmental
Protection Agency.
iii
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CONTENTS
Section
I Conclusions and Recommendations
II Introduction
III Rate of Nutrient Addition to Anderson-Cue Lake
IV Physical Characteristics of the Research Lakes
and Drainage Basins
V Chemical Studies
VI Biology
VII Trophic State Studies of Lakes in North Central
Florida
VIII Acknowledgements
IX References
X Publications
1
3
5
13
23
45
91
129
133
141
v
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FIGURES
Page
IV-1 LOCATION MAP OF ANDERSON-CUE AND McCLOUD LAKES 14
IV-2 TOPOGRAPHY OF ANDERSON-CUE LAKE 15
IV-3 VIEW OF ANDERSON-CUE LAKE LOOKING NORTHWEST
CHECKING RAIN GAGE AT LAKE SITE
UNLOADING SEWAGE EFFLUENT INTO STORAGE TANK
CHECKING HYGROTHERMOGRAPH AT LAKE SITE 17
IV-4 WIND ROSE, ANDERSON-CUE LAKE, OCTOBER, 1967-
SEPTEMBER, 1968 18
IV-5 GROUND AND SURFACE WATER LEVELS ANDERSON-CUE
LAKE 20
V-l DISSOLVED OXYGEN AND WATER TEMPERATURE IN ANDERSON-
CUE LAKE 28
V-2 DISSOLVED OXYGEN AND WATER TEMPERATURE IN McCLOUD
LAKE 28
V-3 TOTAL ORGANIC NITROGEN IN ANDERSON-CUE AND McCLOUD
LAKES 29
V-4 AMMONIA IN ANDERSON-CUE AND McCLOUD LAKES 29
V-5 NITRATE IN ANDERSON-CUE AND McCLOUD LAKES 31
V-6 ORTHO-PHOSPHATE IN ANDERSON-CUE AND McCLOUD LAKES 31
V-7 TOTAL PHOSPHATE IN ANDERSON-CUE AND McCLOUD LAKES 32
V-8 LATERAL VARIATIONS OF AMMONIA IN ANDERSON-CUE LAKE
JANUARY, 1968 36
V-9 LATERAL VARIATIONS OF ORTHO-PHOSPHATE IN ANDERSON-
CUE LAKE, JANUARY, 1968 36
V-10 AMMONIA AND PHOSPHORUS CONCENTRATIONS AROUND NUTRIENT
OUTFALL -- JANUARY 1969 37
V-ll DIURNAL VARIATIONS IN ANDERSON-CUE LAKE 39
vi
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FIGURES (cont)
Page
V-12 NITROGEN IN ANDERSON-CUE SEDIMENTS 40
V-13 PHOSPHATE IN ANDERSON-CUE SEDIMENTS 40
V-14 PERCENT VOLATILE SOLIDS AND TOTAL IRON IN ANDERSON-
CUE SEDIMENTS 41
V-15 TEMPORAL CHANGES OF AQUEOUS AMMONIA IN LAKE WATER 43
V-16 TEMPORAL CHANGES OF AQUEOUS ORTHO-PHOSPHATE IN
LAKE WATER 43
VI-1 ANNUAL VARIATION OF PRIMARY PRODUCTIVITY IN ANDERSON-
CUE AND MeCLOUD LAKES 54
VI-2 DIURNAL VARIATIONS IN PRIMARY PRODUCTION DURING 1968 58
VI-3 ANNUAL VARIATION OF CHLOROPHYLL a IN ANDERSON-CUE
AND McCLOUD LAKES 62
VI-4 HORIZONTAL DISTRIBUTION OF CHLOROPHYLL a IN ANDERSON-
CUE LAKE 64
VI-5 CARBON-14 FIXATION BY PHYTOPLANKTON STIMULATED WITH
100 ygm PHOSPHORUS 67
VII-1 AIACHUA COUNTY LAKES 94
VII-2 DRAINAGE BASINS AND GEOLOGIC MAP OF AIACHUA COUNTY 96
VII-3 CORRELATION BETWEEN SODIUM AND CHLORIDE FOR 33 LAKES 108
VII-4 CORRELATION BETWEEN CALCIUM AND BICARBONATE ALKALINITY
FOR 33 LAKES 108
VI1-5 CORRELATION BETWEEN TOTAL NITROGEN AND TOTAL PHOS-
PHATE 110
VII-6 CORRELATION BETWEEN COD AND COLOR 110
VII-7 TURBIDITY VERSUS THE INVERSE OF SECCHI DISC 111
VII-8 PRIMARY PRODUCTION VERSUS TOTAL ORGANIC NITROGEN 111
VII-9 RELATIONSHIP BETWEEN PRIMARY PRODUCTION AND DEPTH 113
VII-10 RELATIONSHIP BETWEEN CHLOROPHYLL a AND PRIMARY
PRODUCTION 113
vii
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FIGURES (cont)
Page
VII-11 LOCATION OF LAKES IN LOWER OKIAWAHA RIVER BASIN 115
VII-12 LOCATION MAP SHOWING MAJOR LAKE STUDY AREAS 121
VII-13 DENDOGRAM OF COLORED AND CLEAR LAKES CLUSTERED WITH
RESPECT TO SEVEN TROPHIC INDICATORS 125
VII-14 ANNUAL NITROGEN AND PHOSPHORUS LOADING RATES VERSUS
MEAN DEPTH FOR THE FIFTY-FIVE LAKES 126
viii
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TABLES
III-l ESTIMATED NUTRIENT BUDGET FOR LAKE MENDOTA,
WISCONSIN 8
III-2 SOURCES AND SINKS FOR THE NUTRIENT BUDGET OF A LAKE 9
III-3 AMOUNT AND NUTRIENT CONTENT OF RAINFALL AT ANDERSON-
CUE LAKE, 1968 10
III-4 PARTIAL NUTRIENT BUDGET FOR ANDERSON-CUE IAKE, 1968 11
IV-1 ANDERSON-CUE LAKE -- HYDROLOGICAL DATA 21
V-l CHEMICAL COMPOSITION OF ANDERSON-CUE AND MeCLOUD
LAKES AND RAINFALL 25
V-2 TEMPERATURE AND DISSOLVED OXYGEN: ANNUAL AVERAGES
AT THREE DEPTHS IN STATIONS 4, 7, 11 26
V-3 COMPARISON OF AVERAGE CONCENTRATIONS OF SOME BIO-
GENIC PARAMETERS AT THREE DEPTHS IN STATIONS 7 AND 11 35
V-4 COMPARISON OF AVERAGE CONCENTRATIONS OF SOME BIO-
GENIC PARAMETERS AT THE ROUTINE SAMPLING STATIONS 36
VI-1 GROUPS OF MICROSCOPIC ALGAE AND PROTOZOA IN DE-
TAILED ANALYSES OF FIVE DATES IN 1967-68 IN McCLOUD
AND ANDERSON-CUE LAKES, AND THE NUMBER OF OCCURRENCES 51
VI-2 COMPARISON OF AVERAGE CONCENTRATIONS OF SOME BIO-
GENIC PARAMETERS IN EXPERIMENTAL LAKES 1968-70 53
VI-3 A PRIMARY PRODUCTIVITY VALUES FOR ANDERSON-CUE IAKE 55
VI-3 B PRIMARY PRODUCTIVITY VALUES FOR McCLOUD LAKE 56
VI-4 CHLOROPHYLL a LEVELS IN ANDERSON-CUE AND McCLOUD
LAKES "" 61
VI-5 ALGAL GROWTH RESPONSE TO NUTRIENTS 65
VI-6 AMMONIA UPTAKE BY ALGAE IN ANDERSON-CUE WATER 66
ix
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TABLES (cont)
VI-7 STANDING CROP ESTIMATES OF ANDERSON-CUE AND
McCLOUD LAKES 69
VI-8 EXTRACTIVE PHOSPHATE AND ALKALINE PHOSPHATASE 73
VI-9 FOOD OF LABIDESTHES SICCULUS 74
VI-10 DETERMINATION OF ZOOPLANKTON WEIGHTS IN ANDERSON-
CUE AND McCLOUD LAKES 75
VI-11 ZOOPLANKTON DENSITIES AND CALCULATED BIOMASS FOR
AUGUST 1967 76
VI-12
VI-13
VI-14
VI-15
VII-1
VII-2
VII-3
VII-4
VII-5
VII-6
VII-7
VII-8
ZOOPLANKTON DENSITIES AND CALCULATED BIOMASS FOR
AUGUST 1968
A PARTIAL FAUNAL LIST FROM LAKES ANDERSON-CUE
AND McCLOUD
SOME REPRESENTATIVE RATES OF SECONDARY PRODUCTION
IN AQUATIC ECOSYSTEMS
MONTHLY PREDATION PRESSURE BY E. FUSIFORME AND H.
FORMOSA IN LAKES ANDERSON-CUE AND McCLOUD 1969-70
LAKES IN AIACHUA COUNTY
PARAMETERS MEASURED IN LAKE STUDY
TROPHIC CHARACTERISTICS OF LARGE LAKES IN AIACHUA
COUNTY
TROPHIC CHARACTERISTICS OF MEDIUM-SIZE AIACHUA COUNTY
LAKES
TROPHIC CHARACTERISTICS OF SMALL LAKES IN AIACHUA
COUNTY
TROPHIC CHARACTERISTICS OF PONDS AND LAKELETS IN
AIACHUA COUNTY
PHYSICAL CHARACTERISTICS OF LAKES IN OKIAWAHA BASIN
CHEMICAL AND BIOLOGICAL CONDITIONS IN OKIAWAHA LAKES
77
79
84
87
93
98
99
101
103
105
114
OCTOBER, 1968 117
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TABLES (cont)
Page
VII-9 COMPARISON OF MAJOR IONS IN LAKE APOPKA IN 1924
AND 1968 118
VII-10 MEANS, STANDARD DEVIATIONS AND CORRELATION MATRIX
FOR SEVEN TROPHIC STATE INDICATORS 122
VII-11 FLORIDA LAKES RANKED WITH RESPECT TO THE TROPHIC
STATE INDEX (TSI) 123
xi
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SECTION I
CONCLUSIONS AND RECOMMENDATIONS
Conclusions
1. Anderson-Cue Lake has been enriched with nutrients and sewage
since March, 1967. Lake response during this period has been
negligible for most of the routine chemical and biological para-
meters. As the data show, using the mean for all years, a sig-
nificant difference does occur for chlorophyll a, but among no
other parameters. We are beginning to visually observe large
increases in the periphyton especially attached filamentous
chlorophyceae. These are species of Mougeotia, Mougeotopsis
and Spirogyra predominantly. Extensive submersed growths of
these organisms have been blanketing the littoral zone for the
past 18 months with a periodicity from about April through early
July. The crop declines in late summer. Although as yet these
are qualitative observations we are fairly confident they re-
present a significant algal response to enrichment. It appears
that at the present level of eutrophy in Anderson-Cue Lake pro-
duction estimates of only phytoplankton may be misleading and
that more reliability regarding the effects of lake enrichment
may be gained by examining the productivity of other segments
of the plant community as well. This means that Florida lakes
of this type undergo a subtle alteration in the early stages
of eutrophication which do not respond to the usual methods of
detection. Examinations of other primary producer compartments
would be fruitful in this respect.
2. Trophic state indices can be established in a quantitative manner
for lakes in this geographic area. The value of being able to
determine a lake's trophic state is far reaching in establishing
future quality standards for surface waters. Whether or not the
indices are completely applicable to lakes in other geographic
areas is not known at the present time. However, preliminary
trials indicate good correlation.
3. Results from studies of the second trophic level have shown the
mean value to be 50 k cal m"2 year"^-. This amount is within
the expected range for lakes exhibiting oligotrophic character-
istics. Thus far effects of enrichment on the zooplankton have
been minimal.
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Attempts to use littoral zooplankton as indicators of trophic
state must be carefully carried out to reduce masking effects
produced by other variables. In this study fluctuations in lake
level obscured changes in the species composition and diversity
of zooplankton induced by eutrophication. Primary production
and temperature are among the most important environmental fac-
tors related to reproduction of littoral zooplankton. Correla-
tions between population density and primary production most
likely could be improved if the organic matter contribution of
periphyton was considered.
Recommendations
This three year study was composed of background data and
nutrient enrichment information. In particular, the TSI (Trophic
State Index) has provided a mathematical formulation of lake eutro-
phication. The experimental lake has shown practically no change
during the nutrient enrichment program. Basically, a review of the
three year data produced one question, "What ecological compartment
has been significantly affected by the N, F and sewage additions?"
Only two alternatives appear possible: (1) the additives were readily
absorbed by the sediment and/or (2) the additives were utilized by
the plants acting as a biological pump to remove the nutrients from
the sediment. Neither of these possibilities has been investigated.
Generally, primary production rates are based exclusively on
the phytoplankton. In determining trophic states such a procedure
appears to be misleading since there are other photosynthetic com-
partments which need to be considered. For example, periphyton and
macrophytes may proliferate in the littoral zone when the influx of
nutrients increases. Increased growths of these plants have been
observed in Anderson-Cue Lake and likely are a result of the enrich-
ment regimen.
Sediment analyses are not normally a parameter of water quality
surveys. However, the history of lakes have been revealed by core
sampling as an entity. While the past conditions of Anderson-Cue are
not of particular interest at this time, the role of nutrient exchange
and benthic algal growth in the sediment-water interface has emerged
as a major point of concern in attempting to forecast early warning
signals of lake deterioration.
Thus, the above discussion brings forth the recommendation of
continued study of these lakes by looking at new areas where the first
warning signs of degradation may be observed.
Specifically, this study showed Anderson-Cue to be phosphorous
limited. Recent investigations at the EPA facility in Athens, Georgia,
indicate carbon as another enrichment parameter. Carbon content anal-
ysis in the Anderson-Cue community would provide much needed informa-
tion. Additionally, the natural nutrient input to these lakes must be
defined. So far only rain water has been examined.
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SECTION II
INTRODUCTION
Florida has a vast and valuable resource of fresh water considering
the springs and nearly 8,000 (greater than one acre) lakes found with-
in the state. Practically all of these surface waters are useful in a
recreational sense and for this reason Florida appeals greatly to
tourists everywhere within this country and Canada. Fishing, boating
and various contact water sports are enjoyed by both residents and out-
of-state visitors throughout the year. Therefore, the conservation
of this fresh-water resource is most important to the state's economy.
However, since water is so intimately involved in the total well
being of the environment, impairment of aquatic systems in varying de-
grees will affect all the biota including man within a particular eco-
system. Essentially, the water quality of lakes and other fresh-water
resources mirrors the status of the total environment.
Over the years, Florida lakes have been enriched gradually with
nutrient salts from the land. Encroaching urbanization and intensive
agricultural practices have, however, increased nutrient addition to
lakes on an unprecedented scale in recent years. This enrichment has
accelerated the eutrophication of surface water thereby shortening the
lives of lakes and generally impairing the quality of the water.
This problem, which can be reflected nationally, is acute in
Florida. The shallow lake basins, long hours of sunlight and mild
winter temperatures are some of the factors which make surface water
particularly susceptible to the effects of enrichment and lead to sus-
tained algal blooms throughout the year. The most classic example in
Florida is Lake Apopka near Orlando. This is a 30,000-acre lake
(12,145 hectares) which has been extensively enriched by fertilizers
from bordering citrus and winter vegetable farms, municipalities, and
citrus processing plants. A hyacinth eradication program employing
herbicides over the last 20 years has left a flocculant bottom layer
of undecomposed plant residues. These unconsolidated sediments accord-
ing to a recent Federal Water Quality Administration report (1968)
cover 90 percent of the lake bottom. Fish reproduction in Lake Apopka
is prevented by the lack of suitable areas for spawning and by a per-
sistent anaerobic environment.
A similar process is occurring in many other lakes within the
state. Although the visible effects of eutrophication are well docu-
mented, very little real knowledge exists regarding the interplay of
environmental parameters during lake enrichment. Ultimately management
systems for whole drainage basins must be devised if the eutrophication
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problem is to be dealt with effectively. First, however, it is neces-
sary to understand eutrophication in quantitative terms and in part to
find the most effective combinations of enriching substances and de-
termine how these relate for example, to the physical environment of
lake morphology, climate and various edaphic factors. The present level
of knowledge relative to cycling of biogenic materials is primitive and
more experimental work is badly needed in this area. Recent work by
Kerr e_t al (1970) may shed some insight on this problem. Ultimately to
offer the maximum use of a lake to those living within the basin we
must know what enrichment stress can be placed on surface water without
measurably impairing its quality.
This can be brought about only by long-term research. Pnojects
such as described herein, using whole lakes as experimental units, are
few in this country. More are needed especially in varying geographic
locations if we are to understand completely the eutrophication process.
The site for most of this study was in sandy, scrub-oak terrain
near Melrose, Florida, about 25 miles east of Gainesville. There are
numerous lakes in this area. Two of these (Anderson-Cue Lake and
McCloud Lake) located on private property were selected through the
cooperation of the owners. The isolated location of these lakes assured
freedom from outside interference and urban or agricultural influence.
Considerable effort was exerted in 1966 to establish a field station at
the lake site and to install appropriate instrumentation. Background
data on the chemistry and biology of the lakes were obtained in order
to be certain of their similarity and trophic state. Nutrient enrich-
ment of Anderson-Cue Lake has been continuous since March, 1967, and
during this time both routine monitoring and special studies have been
carried out in the two lakes comprising the experimental system.
In 1968 eutrophication research was extended to other lakes of
various types and exhibiting varying trophic stages in the north central
Florida area. For comparative purposes eutrophic lakes in the Oklawaha
chain were also included.
Useful information is gained from programs of this kind since
it has helped point the way to the development of a realistic index of
trophic state for Florida lakes. In addition valuable base line infor-
mation is obtained concerning water quality in north central Florida.
From studies of this kind will emerge patterns for lake management.
Since lakes are slow to change, a considerable lag may ensue
before lakes respond to restorative measures. Therefore, it is essential
to regulate the pollution stress on lakes so as to maintain a desirable
level of water quality at a stage where preventive measures will suffice.
Hopefully ecosystem management models of whole lake basins will provide
the means to accomplish these objectives.
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SECTION III
RATE OF NUTRIENT ADDITION TO ANDERSON-CUE LAKE
Previous Fertilization Studies
One approach to studying eutrophication is to artificially
enrich (eutrophy) a lake at a controlled rate and measure all the para-
meters which define trophic state. The problem then becomes a matter
of relating the response of a lake (in terms of trophic structure) to
the degree and rate of nutrient enrichment. The lake thus serves as a
general model for the process; this approach has been used in the pre-
sent study. Intentional fertilization of lakes for scientific purposes
is not a new concept. Stewart and Rohlich (1967) recently reviewed
previous experiments on lake fertilization. Einsele (1941) reported
one of the first experiments on lake fertilization. He applied slug
doses of superphosphate to a small German lake in 1937 and 1938. Tem-
porary increases in the phytoplankton of the lake were found but the
lake soon returned to normal. A number of investigators (e.g. Ball,
1948a, b; Langford, 1950; Nelson and Edmondson, 1955; Hooper and Ball,
1964) have attempted to increase the productivity of fish ponds by
adding fertilizer. These attempts have had only moderate success. In
most fertilization experiments, nutrients have been added in high slug
doses rather than continuously. While temporary effects have been
noted, the ponds or lakes usually returned to their original conditions
in short periods of time.
Induced circulation by aeration or actual pumping of hypolimnion
water into the epilimnion has been proposed by Easier (1957) and
Hooper e_t al (1952) to render nutrients within a lake more available
to phytoplankton. However, unless the sediments were actually dis-
turbed by aeration, the long-term effect of this process would seem
to be the reverse of that intended. Aeration would tend to keep the
hypolimnion oxygenated and maintain an oxidized microzone at the sedi-
ment water interface which decreases the release of nutrients from the
sediments.
Nutrient Loading Rates Into the Experimental Lake
Because of the nature and purpose of previous fertilization
efforts, results from these studies are not directly applicable to
the problem of cultural eutrophication. Man-induced eutrophication
is characterized by a more or less continuous addition of nutrients
to a lake from such sources as sewage effluent and urban and agri-
cultural runoff, while most previous fertilization attempts have used
sporadic or one-time applications of fertilizer. Generally, sufficient
background data were obtained to describe the trophic state of a lake
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and its natural temporal variations. The study reported here is viewed
as a long-term effort to follow the effects of a controlled nutrient
input on a lake's trophic state. Two small lakes are involved; one lake
is serving as a control and the other lake is being artificially en-
riched by continuous and controlled addition of nutrients. A variety of
routine chemical and biological data on the lakes is being collected
along with routine physical and climatic data in order to identify fac-
tors affecting the rate and severity of eutrophication.
Chemical and biological measurements during 1966 and early 1967
established the oligotrophic nature of Anderson-Cue Lake. In March,
1967, nutrient additions to the lake were begun. It was decided to add
sufficient nitrogen to raise the total N content of the water 0.50 mg N/l
over a period of one year (assuming all nitrogen would stay in solution).
This is equivalent to 500 mg/m3-yr or about 10 mg/m -week. The volume
of Anderson-Cue Lake was estimated to be 248,000 m^. Thus a weekly load-
ing of 2.48 kg N was desired. This was achieved by adding 21.2 Ibs of
ammonium chloride to 300 gallons of sewage effluent, which was trucked
out to the lake site and fed from a holding tank into the lake with a
chemical feed pump at a rate of 1.8 gal/hr. The nutrient outfall is
located 2 ft below the surface and 200 ft off the scuth shore of the
lake in about 10 ft of water.
It was decided to increase the total phosphorus content of the
lake by 0.0427 mg P/l in one year. This is equivalent to 42.7 mg/m^-yr
or 0.854 mg/nr-week. For the lake a loading rate of 0.212 kg P/week is
indicated. This was achieved by adding 2.47 Ib of NasPO^ to the sewage
effluent each week.
Originally it was planned to add only sewage effluent to the
experimental lake. This would have been feasible if Berry Pond
(one acre surface, maximum depth, 13 ft) could have been used as ori-
ginally planned, but its trophic characteristics obviated this plan.
Nearly a million gallons of sewage effluent would have to be trans-
ported to Anderson-Cue Lake annually for the desired nutrient loading
rate. Thus logistics precluded the use of sewage effluent alone, and
it became necessary to enrich the effluent with nitrogen and phosphorous
compounds.
After two years, the method of nutrient addition was changed to
direct application of the chemicals to the lake by towing a burlap bag
behind a motor boat. The towing pattern was simply to make a large
circle in the middle of the lake. This method was considered an im-
provement since a residue was often found in the holding tank.
Nutrient Budgets for the Experimental and Other Lakes
The above nutrient addition rates compare closely with those
estimated for the nutrient budget of Lake Mendota, Wisconsin, by Lee
e£ a_l (1966) . This eutrophic lake receives a heavy influx of nutrients
from agricultural drainage, but ground water and atmospheric precipi-
tation also make important contributions. The nitrogen loading of Lake
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3
Mendota was estimated to be 556,000 Ib per year, or 534 mg/m -yr. Of
this quantity, Brezonik and Lee (1968) have estimated that two-thirds
or 360,000 Ib remain in the lake and is deposited in the sediments,
while the remainder is lost through the outlet and by denitrification.
The phosphorus budget for Lake Mendota was estimated to be 44,900 Ib
per year or 42.7 mg P/m-^-yr. Table III-l summarizes the computed nu-
trient budget for Lake Mendota.
Relatively few other lake nutrient budgets have been established.
Mortimer (1939) constructed a nitrogen balance for Lake Winder-mere
(England). He found a close balance between input and output -- 326
and 318 metric tons, respectively. Hutchinson (1957) felt that nu-
trient inflow and outflow normally would balance closely in oligo-
trophic lakes, but not in eutrophic lakes. Rohlich and Lea (1949)
reported an extensive nutrient balance on Lake Mendota, Wisconsin.
Of the estimated 156 metric tons of nitrogen entering the lake annually,
only 41 tons left through the surface outlet. Corresponding values for
phosphate were phosphate were 16.4 and 11.6 metric tons. Partial nu-
trient budgets were determined for the lower Madison lakes by Sawyer
e_t a_l (1945). However, only soluble phosphorus and inorganic nitrogen
inputs were measured rather than total values, and the usefulness of
the results is thus impaired. Aside from nutrient balances on Lake
Tahoe (McGauhey e£ al, 1963) and Lake Washington (Edmondson, 1968) no
other definitive nutrient budgets are known. Less detailed budgets
have been drawn for a few other lakes--for example, Lake Pure in Denmark
(Berg, 1958), Castle Lake in California (Goldman, 1961) and western
Lake Erie (Curl, 1959). Various aspects of nitrogen and phosphorus
budgets and sources have been treated by numerous workers. Brezonik
(1968), Feth (1966), and Fruh (1967) have reviewed these studies in
considerable detail.
Table III-2 lists the most common nutrient sources and sinks for
lakes. Only some of these are applicable to the study lakes. Artifi-
cial enrichment represents the most significant nutrient source for
Anderson-Cue Lake. The possible natural sources of nitrogen are bio-
logical fixation, atmospheric precipitation, air-borne particulates and
surface and subsurface runoff. Preliminary results indicate the rain-
fall directly on the lake surface is the most important natural source.
Nitrogen fixation has not yet been measured in the lake, but the near
absence of blue-green algae in the biota of the lake implies that it
does not occur. While bacterial fixation is possible, available carbon
substrates are low and indicate the source is probably negligible.
Contributions from runoff appear to be small. The amount of runoff
draining into the lake is apparently low, and the soil is so nutrient
depleted that rainfall runoff would pick up little or no additional
nutrients in passing through and over the soil.
Measurements of the nutrient content of the rainfall were made
periodically in 1967 and 1968. A summary of the results are shown in
Table III-3. The nitrogen content of rainfall appears to be quite
variable. However, these results can be combined with the rainfall
amounts (see Section IV, Table IV-1) to yield an estimate of the total
nitrogen contribution of rainfall to Anderson-Cue Lake. For 1968, 44 kg
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Table Ill-l
ESTIMATED NUTRIENT BUDGET FOR LAKE MENDOTA, WISCONSIN'- *
Source
Municipal and
industrial waste-water
Urban runoff
Rural runoff
Precipitation on
lake surface
Ground water
Nitrogen fixation
Marsh drainage
Appro*. Total
Nitrogen
Contribution
kg-
21,200
(total)
13,700
(soluble)
23,500
(soluble)
43,900
113,000
36,100
252,000
Contribution
%
8
5
9
17
45
14
100
Phosphorus
Contribution
kg-
7,750
(total)
3,680
(soluble)
9,100
(soluble)
64 to
3,460
274
21,240"
Contribution
%
36
17
42
2
2
100
Sink*
Outlet loss
Denitrification
Fish catch
Weed removal
Ground water
recharge
Sediments and
other losses5
Nitrogen
Lost
kg.
41,300
28,000
11,300
3,250
168,000
252,000
Lost
%
16.4
11.1
4.5
1.3
66.7
100
1 After Lee et al (1966) and Brezonik and Lee (1988)
* The values presented are only rough approximations
* This total based on 455 kg. per year ot phosphorus in precipitation on the lake surface
* Phosphorus sinks have not been determined but outlet loss and sediment deposition probably account for most of the phosphorus
' By difference between total sinks (assumed to equal total sources) and sum of aU other calculated sinks. Other sinks are probably small, and
sediment deposition accounts for most of the nitrogen in this category.
-------
TABLE III-2
SOURCES AND SINKS FOR THE NUTRIENT BUDGET OF A LAKE
SOURCES
1. Air-borne
Rain water
Aerosols and dust
Leaves and miscellaneous debris
2. Surface
Agricultural runoff and drainage
Urban storm water runoff
Marsh drainage
Runoff and drainage from uncultivated land
Domestic waste effluents
Industrial waste effluents
Wastes from boating activities
3. Underground
Natural groundwater
Subsurface agricultural and urban drainage
Subsurface drainage from septic tanks near lake shore
4. In situ
Nitrogen fixation
Sediment leaching
SINKS
Effluent loss
Groundwater recharge
Fish caught or removed
Weed harvesting
Insect emergence
Evaporation (aerosol formation from surface foam)
Denitrification
Sediment deposition of detrital particles
Inorganic precipitation (for calcium phosphate, and some trace metals)
and deposition into sediments
-9-
-------
Table 111-3
AMOUNT AND NUTRIENT CONTENT OF RAINFALL AT
ANDERSON-CUE LAKE, 1968
Date
2-19
2-26
3-4
3-11
4-15
5-6
5-13
5-27
6-24
7-5
7-25
R-O
(J j£l
8-19
9-3
9-16
10-11
10-19
11-11
19.9
Amount1
Inches
1.00
0.25
0.35
1.20
0.65
0.45
0.75
3.35
6.65
4.00
4.65
0 c=;
V/»Od
2.10
10.85
4.30
2.85
3.70
3.60
2.9.5
TON
mg/1
__
0.57
0.67
0.64
0.33
0.11
0.24
0.39
0.01
n ^0
U.QU
0.34
0.07
0.07
0.12
0.11
0.23
0.54
NH:,-N
mg/1
0,46
0.23
0.80
0.86
0.33
0.10
0.0
0.02
0.02
0.05
0.01
0.14
0.11
0.05
0.21
0.07
0.18
NO3-N
mg/1
0.40
0.94
0.26
0.24
0.27
0.30
0.15
0.05
0.14
0.09
0.08
ft OQ
\j.£\j
0.22
0.09
0.16
0.11
0.04
0.05
0.11
o-PO4
/*g/l
230
20
25
18
2.2
28
20
. .
9
10
8
33
__ _
5
12
4
25
18
t-PO<
Mg/1
__
__
30
30
9(1
£t\J
70
20
_
30
1 Total amount of rain in period from date on previous line to the date listed on
the line. First line indicates rainfall from Jan. 1 to Feb. 19; last line indicates
amount of rain from Nov. 12 to the end of the year.
-10-
-------
TABLE III-4
PARTIAL NUTRIENT BUDGET FOR ANDERSON-CUE IAKE, 1968
Sewage and nutrient mixture
Rainfall on lake surface
Total
NITROGEN
kg
124
44
168
mg/1 of lake water
0.67
0.24
(T91
Other possible nitrogen sources not completely evaluated are
nitrogen fixation, groundwater seepage, subsurface runoff and air-
borne particulates (leaves, etc.)- Present information indicates all
these except perhaps the last were insignificant in 1968.
Sewage and nutrient mixture
Rainfall on lake surface
Total
PHOSPHORUS
10.60
2.67
13.27
mg/1 of lake water
0.057
0.014
0.071
Other possible phosphorus sources are groundwater, subsurface
runoff and air-borne particulates. Present information indicates the
first two were insignificant, but there is insufficient information to
evaluate the last source.
This is the concentration which would result if the amount of nutrient
in column 1 were diluted to the volume of the lake (approximately 150
acre-feet or 185,000m3).
nitrogen was added to the lake by rainfall directly on the lake surface.
(This value corresponds with 49.4 kg nitrogen added to the lake by
rainfall during 1967, as previously computed by Brezonik and Putnam, 1968).
By comparison, about 124 kg N was added by the nutrient mixture. Ac-
tually a greater disparity between these two sources exists than is
indicated by the magnitude of the two numbers. The rainfall contribu-
tion is diluted in a large volume of water, whereas the nutrient mix-
ture is highly concentrated and contributes an insignificant amount of
water to the lake. Phosphate analyses from 1968 indicate a wide range
of phosphate in rain water. The data indicate that about 2.7 kg P was
contributed by rainfall in 1968. This compares with 10.6 kg added to the
lake in the nutrient mixture. These results are summarized as a nu-
trient budget for Anderson-Cue lake in Table III-4.
-11-
-------
Sampling Program
The duration and frequency of the sampling program is detailed
in Section V (Chemical Studies) and Section VI (Biology). The tests
conducted and the methods utilized are displayed in Appendix A and B.
Generally, background data collection began in January, 1966 on
a bi-monthly basis. Nutrient addition was initiated in March, 1967.
Bi-monthly sampling was conducted through January, 1970.
Several special- investigations were conducted in conjunction
with these regular investigations. The special studies included the
weekly collection of samples for zooplankton analyses from January, 1967
until December, 1968. This study correlated population dynamics with
productivity. A subsequent bi-weekly research program dealt with the
interactions of zooplankton and their fish predators. This research
continued from June, 1968 through April, 1970.
An intensive program was undertaken to develop a quantitative
trophic state index using multivariate statistical techniques. The
sampling schedule used in this study was designed to provide informa-
tion on the average chemical, biological and physical characteristics
of fifty-five central Florida lakes over a one year period.
Systematic sampling of the fifty-five lakes commenced in June,
1969. It was decided to sample all fifty-five lakes at four-month
intervals for a period of one year. Hence, the subsequent fifty-five
lake sampling periods were in October, 1969, February, 1970 and June,
1970. From the fifty-five lake experimental group a sub-group of nine-
teen lakes was selected. These lakes were sampled at two-month inter-
vals so that in addition to being sampled with the main group they were
sampled in August, 1969, December, 1969 and April, 1970. The nineteen
lakes were selected on the basis of being representative of several
trophic types of lakes and/or being of special interest. It was felt
that this sub-group of lakes could be used to reflect seasonal trends
in lake characteristics without sampling the entire fifty-five lakes on
a closer time interval.
-12-
-------
SECTION IV
PHYSICAL CHARACTERISTICS
OF THE RESEARCH LAKES AND DRAINAGE BASINS
General
Anderson-Cue and McCloud Lakes (see Figure IV-1) are located in
a region of high sand hills with many circular to elliptical basins
which have resulted from solution of the underlying limestone. Both
lakes have small drainage basins with no influent or effluent streams.
The tops of many of the surrounding hills reach elevations of 190
to 220 ft, MSL. Westward at Melrose the terrain changes from sand hills
to the Okefeenokee Terrace, a poorly drained terrace 140 to 160 ft, MSL.
Eastward, beyond Baywood, the sand hills are bound by lower marine ter-
races. The immediate area of the research lakes is the Trail Ridge
portion of the Central Highlands.
Three hydrographic surveys of Anderson-Cue Lake have been made
since the fall of 1965. Echo soundings were made in November, 1965;
a stadia survey (including topography of the basin) was made in July-
August, 1967; and echo soundings were again made in March, 1968. Using
these data a topographic map of the lake and surrounding area was pre-
pared and is shown in Figure IV-2. The highest level shown on the map
was the shoreline which stood at 125.78 ft, MSL, in March, 1966, at
which time the lake had a surface area of 19.3 acres and a volume of
approximately 201 acre-feet. When it was decided to use McCloud Lake
instead of Berry Pond as the control body of water in late 1966 the
volume of water in McCloud Lake exceeded that in Anderson-Cue Lake by
approximately 15 percent. This information was obtained by stadia
survey.
Yearly excess precipitation over evaporation (30 year record)
is 12 to 18 in. in the xeric hills surrounding Anderson-Cue lake.
(These data are not applicable to the research lake itself.) The ex-
cess precipitation and runoff percolate downward through breaks in the
sands and clays of an aquifuge that overlies the Floridan aquifer. The
influent drainage has resulted in a subsidence karst landscape which
forms a principal recharge area in North Florida for the Floridan
artesian system. Analyses of the water level data for Anderson-Cue
Lake, the surrounding water table data, and the rainfall and evaporation
records indicate that there is very little contribution from surface
and subsurface runoff to the lake. Sands covering the basin are porous.
Downward seepage rates are high and surface runoff is exceedingly low.
-13-
-------
»w
?<&
Figure IV-1 . Lex:otion Map of And«f»on-Cue and McCloud Lake*.
-------
Figure IV-2. Topography of Anderson-Cue Lake.
-15-
-------
Geology
Materials exposed in the sand hills are largely of two types:
very fine surface sands and the underlying kaolinic gravels, sands and
sandy clays. These sediments are known as the Citronelle Formation.
Well borings show an aquifuge of from 80 to 100 ft of phosphatic sands,
sandy clays and clays lying below the surface. These materials are
known as the Hawthorne Formation of Lower and Middle Miocene Age. Under-
lying the Hawthorne Formation is the Floridan aquifer, the upper portion
of which is the Ocala Limestone of Eocene Age.
The piezometric surface of the water in the Floridan aquifer is
approximately 90 ft above MSL in the vicinity of Anderson-Cue Lake.
The porous sand and gravel of the Citronelle Formation contain a perched
water table above the aquifugethe Hawthorne Formation. Anderson-Cue
Lake is itself a perched lake. The lake level is the result of a bal-
ance between precipitation, evaporation and outflow into the water
table aquifer and Floridan aquifer.
The vegetation in both lake basins is sparse and primarily scrub
oak, indicative of poor nutrient conditions. There is no human habi-
tation in either basin. The major source of nutrients for the lakes in
their natural states appears to be from the atmosphere via precipitation
and air-borne particulates.
Instrumentation
A Gurley water level recorder with staff gage and a recording
rain gage were installed at Anderson-Cue Lake in February, 1966.
In September, 1967, an Aerovane wind recorder and Foxboro
hygrothermograph were installed. The transmitter for the wind recorder
was mounted on a pole approximately 150 ft from the south shore of the
lake and three feet above the water surface. Examples of some of the
instrumentation are shown in Figure IV-3.
Meteorological and Hydrological phenomena
Anderson-Cue Lake lies in a shallow valley oriented in a NNE to
SSW direction and is surrounded by scrub oak and pine trees. These
characteristics have a marked effect on the air-flow over the water
surface. The air speed in general is calm to light (0-7 mph). The
prevailing winds are from 30 to 60 degrees (NNE to NE) and from 210
to 240 degrees (SSW to SW). When a tropical storm or frontal system
passes over or close to NE Florida the wind direction is influenced by
such phenomena and higher wind speeds are recorded. A wind rose for the
period October, 1967 to September, 1968, is shown in Figure IV-4.
-16-
-------
View of Anderson-Cue Lake
Looking Northwest
Checking Rain Gage at Lake Site
Unloading Sewage Effluent
into Storage Tank
Checking Hygrothermograph
at Lake Site
Figure !V-3.
-17-
-------
SCALE: 1mm # 3 HOURS
1-3MPH
Figure \V-4. Wind Rose, Anderson-Cue Lake, October 1967 - September 1968.
-18-
-------
The only significant currents in shallow Anderson-Cue Lake are
wind currents. In bodies of water larger than Anderson-Cue Lake such
surface water currents flow to the right of the wind and set up a clock-
wise circulation. In Anderson-Cue Lake, however, these currents cause
a pileup of water on the leeward shore which is returned by fanouts in
both clockwise and counterclockwise directions.
Many factors must be considered in attempting to explain the
fluctuations of the lake level and the water table in the research
area. These include evaporation, precipitation, and flow to the water
table aquifer and Floridan aquifer. The most complex of these factors
is evaporation. The question arises as to what percent of time in a
certain period was the variation of dewpoint temperature with height
such as to lead to condensation on or evaporation from the lake sur-
face. An inversion of the dewpoint will develop if the surface acts as
a heat sink to remove water vapor. This condition can be expected during
clear nights when there is strong radiation from the ground; during
times of high relative humidity; and during times of build-up of sur-
face inversions which occur frequently in the Anderson-Cue Lake area.
In fact, about 50 percent of the time the water vapor flux is directed
downward. This reversal of evaporation is evident during non-daylight
hours when winds are persistently less than 7 mph and relative humidity
greater than 90 percent.
It is interesting to note from the rain gage records of the past
year that during the periods when the vapor flux is directed upward
(generally from 0800 hr to 1800 hr) approximately 0.12 to 0.15 of an
inch of water is evaporated daily. This indicates the large amount of
evaporation from the lake surface that can be expected unless the amount
of precipitation plus condensation received when the lake acts as a
heat sink can overcome the evaporation losses and losses to the water-
table aquifer and Floridan aquifer.
Water in the water-table aquifer is unconfined so that its surface
is free to rise and fall with the variance in rainfall. Rainfall on
the Anderson-Cue Lake basin for the period March 28, 1966, through
June 30, 1968, was deficient by 13.85 in. (the closest "departure from
normal" data are accumulated at Gainesville, approximately 20 miles to
the west). For the period November 2, 1967 through June 30, 1968 the
deficiency was 8.56 in. This is shown in Figure IV-5 (refer to Figure
IV-2 for location of test wells). Because the piezometric surface of
the Floridan aquifer is below the level of the lake, water cannot move
from the Floridan aquifer to the lake. The net groundwater flow during
the period of study has been composed only of outflow to the water-
table aquifer and to the Floridan aquifer, the greater flow being to
the water-table aquifer east of the lake. Note the level of Well No. 4
in Figure IV-5.
As shown in Table IV-1, for the period March 28, 1966 through
November 30, 1968, evaporation losses exceeded rainfall by 8.35 in.
and approximately 65 acre feet of lake water was lost to the aquifers.
-19-
-------
125
123 -
122
121
120
119
**§
=4 U-
_c
30
d
' <
1 Oi
\
(N
.E
§
CO
\
x%
X V
\\
Well No.
1
2
3
i,
--.- Lake Level
\ ^
\ '
See Fig. IV-2 for well locations.
f
^*
Figure IV-5. Ground and Surface Water Levels Anderson-Cue Lake.
-------
TABLE IV-1
ANDERSON-CUE LAKE HVTDROLOGICAL DATA
Dates
3/28/66
4/26/66
.5/25/66
6/22/66
7/21/66
8/18/66
9/13/66
10/11/66
11/08/66
12/06/66
1/03/67
3/28/67
5/02/67
5/31/67
6/27/67
3/01/67
9/06/67
10/03/67
11/02/67
12/03/67
1/04/68
1/31/68
2/29/68
3/31/68
4/30/68
5/31/68
6/30/68
7/30/68
8/31/68
9/30/68
10/31/68
11/30/68
12/30/68
1/31/69
2/28/69
3/31/69
4/30/69
5/31/69
6/30/69
7/31/69
(1)
Lake Evaporation (in.)
(2)
Rainfall (in.)
(est)
Summary: 186.73 (1)
-171.69 (2)
15.04 in.
(3)
Lake Level (ft-MSL^
125.78
125.33
125.04
124.69
124.25
124.43
124.41
124.51
124.21
123.75
123.61
123.61
122.99
122.83
123.07
123.33
123.81
123.66
123.46
122.99
123.07
122.63
122.17
121,59
120.83
120.49
120.02
119.54
120.45
120.75
121.09
121.19
121.09
120.87
120.89
120.67 (eat)
120.45
120.49
120.01
120.87
-(55.40 in.)
(3)
55.40
-15.04
40.36 in. or approximately
56 acre/ft.
NOTE: Lake evaporation is computed from data collected at the U.S.
Weather Bureau evaporation station at Gainesville, Florida. Pan coeffi-
cients are those used for" Lake Okeechobee, Florida: Kohler, M.A., 1954,
Lake and Pan Evaporation in Water Loss Investigations-Lake Hefner Studies,
Technical Report: U.S. Geological Survey Prof. Paper 269, p. 128.
-21-
-------
For this period, the residence time of water in Anderson-Cue Lake has
been calculated to be 5.43 years. The same calculation holds true for
McCloud Lake (control) which rises and falls at the same time and in
the same proportion as Anderson-Cue Lake.
-23-
-------
SECTION V
CHEMICAL STUDIES
Introduction
Trophic state is manifested by a variety of chemical and
biological parameters. This section will summarize the routine chemi-
cal data obtained on the two study lakes; biological results will be
presented in the following section. Results for Anderson-Cue Lake ex-
tend for a period of four years-from 1966 to the present. McCloud
Lake has been sampled routinely since the beginning of 1967. During
1966 and 1967 sampling was approximately bi-weekly, especially for the
important nutrient parameters. Sampling has been on a monthly basis
since January, 1968, because short term variations have been found to
be rather small. Monthly sampling has also allowed more time for
other special studies. The objective of routine sampling is to define
changes in the chemical and biological composition of the lake as it
undergoes controlled eutrophication. To accomplish this requires a
representative sampling program with careful attention to possible
temporal, lateral and depth variations in composition.
Three permanent sampling stations were located in Anderson-Cue
Lake. Stations 4 and 7 are in the centers of the lake's two basins,
and Station 8 is on the south shore in about 3 feet of water. The lo-
cation of these stations is shown in Figure IV-1. Two permanent sta-
tions are located in McCloud Lake, Station 11 near the center of the
lake, and Station 12 near the north shore in 3 feet of water. Samples
were taken at three depths (top, middle and bottom) at Stations 4, 7
and 11, and at mid-depth at the shore stations (8 and 12). For more
detailed determinations of lateral variability, a sampling grid of
about 50 stations was established on Anderson-Cue Lake; these are in-
dicated in the isopleth maps shown in later discussions of these studies.
Parameters measured routinely (bi-weekly or monthly) include dissolved
oxygen, pH, conductivity, acidity, dissolved and suspended solids,
ortho and total phosphate, total and particulate organic nitrogen,
ammonia, nitrite, and nitrate. In addition, data have been routinely
collected on physical conditions such as water temperature and Secchi
disc transparency. Other major and minor chemical constituents have
been determined less frequently. These include chloride, sulfate,
calcium, magnesium, sodium, potassium, silica, iron, manganese, chemical
oxygen demand and biochemical oxygen demand. Chemical characterization
of lake sediments has included determination of percent volatile solids,
total organic nitrogen, ammonia, total phosphate, iron, and manganese
(see Appendix A for methods).
-23-
-------
Chemical Characteristics
The two lakes are typical of the small lakes in the Trail Ridge
portion of the Central Highlands of Florida. Table V-l summarizes the
chemical characteristics of the lakes. Few significant changes in
gross chemical composition have been noted during the period of record;
hence the values in Table V-l are mean values for each lake during the
period of record. Both lakes are colorless, low in dissolved solids
and extremely soft. The waters are acidic, with typical pH values
ranging between 4.6 and 5.5. The waters have little buffer capacity and
essentially no alkalinity. Consequently, acidity titrations have been
used to estimate total C02. Specific conductance has increased in
Anderson-Cue Lake from about 25 ymho cm~l to about 40 ymho cm~l over the
last two years. Corresponding increases in McCloud Lake have been less-
from 30 to 35 ymho cm~*. Some of the increase would seem to be the re-
sult of excess evaporation over precipitation during the period; nutrient
additions were probably responsible in part for the increase in the ex-
perimental lake.
The low dissolved solids and ionic content of the lakes are
indicative of the waters' origin, i.e. atmospheric precipitation.
Table V-l lists some comparative values for the chemical composition of
rain water at the lake site. Concentrations of major ions compare
reasonably close for the lakes and rain water. The ionic content of
rain water varies considerably, but the values in Table V-l represent
approximate ranges for the various ions. The data are too sparse for
reliable estimates of mean rainfall composition, which would be useful
in deriving a chemical model for the lake waters from rainfall compo-
sition and possible chemical interactions between rain water runoff and
soil constituents. The primary reason for studying the composition of
rain is to determine its significance as a nutrient source. The rain-
fall values for nitrogen and phosphorus species in Table V-l are mean
values revealing the importance of rain as a nutrient source, especially
for lakes unaffected by cultural sources.
While concentrations of major ions are not likely to limit primary
production in either lake, the paucity of several is likely to select
against certain types of organisms. Low silica probably is a contribu-
tor to the small diatom populations; low calcium and magnesium indicate
the waters are unsuitable for macrophytes like Chara and some algae
which prefer hard water. The low pH of these lakes is undoubtedly a
contributing factor for the low populations of blue-green algae, but
encourages the maintenance of a desmid population. The relatively low
nutrient levels favor organisms like Dinobryon and Synura, which pre-
fer such environments (Hutchinson, 1967 ).
-------
TABLE V-l
CHEMICAL COMPOSITION OF
AND McCLOUD LAKES AND
ANDERSON-CUE
RAIN WATER
Constituent Anderson-Cue Lake
Specific conduct.
PH
Acidity as CaCO»
Cl"
S04=
Na
K+
Ca+2
Mg+2
Silica
Total org. N
Particulate org. N
NH3-N
N03--N
Ortho phosphate
Total phosphate
COD
BOD
Sus. solids
Turbidity
31.
4.
3.
6.
5.
2.
0.
0.
0.
0.
0.
0.
0.
0.
0.
65
93
20
25
4
49
51
74
58
14
47
26
234
0014
067
0.0084
0.017
10.7
1.02
5.9
11.1
McCloud Lake
32.29
4.85
3
5
5
2
0
0
0
0
0
0
0
0
0
0
0
10
0
5
8
.50
.93
.0
.81
.25
.61
.57
.10
.42
.21
.105
.0012
.041
.006
.012
.7
.86
.2
.8
Rain Water
10-30
5.3-6.8
1.
0.
0.
0.
1.
0.
0.
0.
0.
0.
0.
0.
74
8
29-1.
13-0.
01-2.
06-0.
32
208
005
209
027
033
85
21
06
35
All values in mg/1 except specific conductance (ytnho con ) and pH.
Nitrogen species are in mg N/l and phosphate in rag P/l.
Mean values for all samples from the mid-lake stations during 1967
and 1968.
3
Nutrient (and Chloride) concentrations are mean values for all deter-
minations in 1968; other values represent range encountered in one to
four determinations during 1967-68.
-25-
-------
TABLE V-2
TEMPERATURE AND DISSOLVED OXYGEN:
ANNUAL AVERAGES AT THREE DEPTHS IN STATIONS, 4, 7, 11
1 2
Station & Temperature Dissolved Oxygen
Depth 1967 1968 1969 1967 1968 1969
4 Top 23.61 22.11 23.05 7.39 7.94 9.08
Mid 23.06 21.74 22.55 7.39 7.96 8.05
Bottom 22.91 21.57 22.66 7.27 7.48 8.20
7 Top 23.42 22.13 23.09 7.66 8.04 8.48
Mid 23.13 21.83 22.71 7.56 8.03 8.34
Bottom 22.90 21.08 22.43 7.37 7.30 8.18
11 Top 23.49 22.65 23.28 7.58 8.07 8.35
Mid 22.78 21.98 22.49 7.50 8.02 8.25
Bottom 21.93 21.73 22.04 6.26 6.90 7.28
Temperature in C
2
Dissolved Oxygen in mg/1
Temperature and Dissolved Oxygen
Neither lake shows much evidence for stable thermal stratification
at any time of the year. Table V-2 summarizes average temperature and
dissolved oxygen at the three depths sampled for Stations 4, 7, and 11.
The maximum difference in average annual temperature from top to bottom
was about 1.5° C for Station 11 in 1967; differences at the other sta-
tions have been 1°C or less. Somewhat larger differences at Station 11
have been found from top to bottom on particular days. During the period
of high water in summer of 1967, 3°C differentials were sometimes found,
but the changes occurred in the bottom few feet, and most of the lake
was freely circulating. Temperature profiles in Anderson-Cue Lake are
normally within one degree Celsius from top to bottom. During periods
of intense warming and calm weather, temporary stratification could
occur in either lake, but we have not yet found such conditions in over
three years of sampling. Water temperatures range from about 12°C in
winter to about 32°C in mid-summer.
Dissolved oxygen profiles also show little change with depth.
Average differences at Stations 4 and 7 in 1967 were only 0.12 and
0.29 mg/1, respectively. Slightly greater differences occurred in
1969; 0.75 and 0.95 mg/1 at Stations 4 and 7, respectively; these may
reflect the somewhat greater production and standing crop in Anderson-
Cue in 1969. Vertical differences at Station 11 were greater (1.2 -
1.3, mg/1) than the Anderson-Cue results for the three years, corrobor-
ating the greater vertical stability of this lake. There is no evidence
-26-
-------
of oxygen depletion in the bottom water of either lake at any time, but
considering the lack of thermal stratification and oligotrophic condi-
tions, this is not surprising. Seasonal variations in dissolved oxygen
largely reflect changes in solubility with temperature. Figures V-l
and V-2 show the average temperature and dissolved oxygen values for
1967, 1968, and 1969 at Stations 7 and 11, respectively. Oxygen values
generally were near saturation, but a tendency toward slight under-
saturation is noted. Rates of photosynthesis and respiration in either
lake are too slow to markedly influence dissolved oxygen, but this should
change in Anderson-Cue Lake as nutrient additions are continued.
Variations in Biogenic Compounds
In routine chemical analyses, greatest attention has been
centered on nitrogen and phosphorus compounds, which presumably are
most critical for primary production, and on other substances whose
concentrations are affected by the activity of organisms. Both lakes
were extremely poor in nutrients before enrichment began. Ammonia
ranged between 0.02 and 0.06 mg N/l; nitrate was less than 0.04 mg N/l,
and total organic nitrogen averaged about 0.3 mg N/l. Ortho-phosphate
was often undetectable and averaged less than 5 yg P/l. Total phosphate
exhibited similarly low concentrations. The above concentration ranges
are for 1966 and early 1967, before nutrient enrichment of Anderson-Cue
Lake. Enrichment began in March of 1967 and is still continuing. Fig-
ures V-3 to V-7 show the seasonal variations in nitrogen and phosphorus
forms in the two lakes from January, 1967 to December, 1969. The points
on each plot represent mean values for the mid-lake stations in each
lake. Differences between the two lakes may have been somewhat greater
than the plots indicate. Occasional high nutrient concentrations were
encountered in the bottom sample of McCloud Lake; these may have re-
sulted from stirring the sediment during sample collection. These are
included in the averages, but are probably not representative of the
lake as a whole.
Seasonal patterns in both lakes are rather similar. With the
exception of total organic nitrogen (Figure V-3), nutrient concentra-
tions are'consistently higher in Anderson-Cue compared to McCloud Lake.
Total organic nitrogen does not appear to exhibit a marked seasonality
in either lake. The' high and erratic nature of the data in mid-1967 is
partially the result of analytical difficulties subsequently corrected.
Concentrations were usually slightly higher in the experimental lake
during 1968 and 1969.
The effect of enrichment on ammonia concentrations is clearly
illustrated in Figure V-4. Ammonia has been consistently higher in
the experimental lake throughout 1967, 1968, and 1969, but differences
became much more pronounced during 1968. There does not seem to be a
major seasonal influence on ammonia; rather concentrations fluctuate
considerably from month to month. It is interesting to note that the
-27-
-------
ro
oo
I -
0,0,
1 1 1 1 1 I 1 1 1 1 1 1 1 1 i ._ i i i i ii
J F M A * I JAS ONDJF HAMJJASONOJFMAUJ JAS OND
IW7 IMS list
Figure V-l. Dissolved Oxygen and Water Temperature in Anderson-Cue Lake
Me Cloud U*.
E "
I »
I
<5
1
1 - 1 - 1 - 1 - 1 - 1
1 - 1 - 1 - 1
JfllAMJJASOHDJFtlAIIJJASONO.JFMAHJJASONO
1967 l«6 tlfj
Figure V-2. Dissolved Oxygen and Water Temperature in McCloud Lake
-------
N5
VO
I
FMAUJJASONOJFyA
Figure V-3. Total Organic Nitrogen in Anderson-Cue and McCloud Lakes
J JASONDJ F M A M J J
Figure V-4. Ammonia in Anderson-Cue and McCloud Lakes
-------
biological forces within the lake can exert an over-riding influence on
the general trend toward increased concentrations resulting from nutrient
input. A decrease from about 0.34 mg NHo-N/1 to 0.06 mg NH^-N/l occur-
red in Anderson-Cue Lake during February, 1968. This corresponded to a
winter bloom of Dinobryon and Synura. After the bloom, ammonia increased
to 0.40 mg N/l within the next month. A similar but smaller decrease
and subsequent increase occurred contemporaneously in McCloud Lake.
Ammonia was being continuously fed into the experimental lake at a rate
equivalent to a 0.1 mg N/l average increase in the water for the two
month period (February and March). With some fluctuations ammonia con-
tinued to increase in Anderson-Cue Lake during 1968 while values in
McCloud Lake showed a much smaller trend. Ammonia in Anderson-Cue Lake
has now increased to levels commonly considered indicative of eutrophy.
Nitrate seasonal patterns (Figure V-5) are nearly identical for
the two lakes, but the experimental lake has consistently higher values
(by about 0.01 to 0.09 mg NCL-N/l). The peak concentrations for both
lakes in 1968 occurred in early February; minimum values were found in
late May. The seasonal pattern probably can be explained by uptake of
nitrate during the late winter bloom and inhibition of nitrification at
warm summer temperatures. Nitrate concentrations have been below
0.10 mg N/l except during the winter of 1968. No winter maximum was
found in 1967. In 1969, peak concentrations occurred in early March
and minimum values occurred in June and July for both lakes.
Ortho-phosphate concentrations in both lakes (Figures V-6) are
normally quite low and follow a similar seasonal pattern. Peak con-
centrations occur from late spring to mid-summer. Values were below
10 yg P/l in both lakes during winter and early spring and again in
fall of all three years. The low phosphate values (except during sum-
mer) indicate phosphorus is probably the limiting eutrophying factor in
Anderson-Cue Lake. The seasonal pattern of ortho-phosphate is rather
the opposite of that found in north temperate lakes and is somewhat un-
expected. This pattern (summer maximum) has been found for ammonia in
some Polish lakes (Karcher, 1939). Data on seasonal variations of phos-
phate in other unstratified lakes are rather sketchy. There seems to
be a consistent trend in the total phosphate of both lakes to higher
values in summer and minimum values in early winter. With few exceptions
concentrations were higher in the experimental lake than in the control,
but the differences were usually not striking. Concentrations increased
greatly in both lakes in early fall of 1968 and reached maximum values
of 93 and 84 yg P/l (average concentrations) in Anderson-Cue and McCloud
respectively, in mid-October. Data for this period in 1967 are not
available for comparison. In August, 1969, total phosphate concentra-
tions reached maximum values of 31 and 23 yg P/l (average concentrations)
for Anderson-Cue and McCloud respectively. Such a rapid and large in-
crease in total phosphate and subsequent rapid decline would seem to
imply an important role for the sediments as a phosphorus source and
sink since they alone would seem capable of providing such amounts to
the water.
-30-
-------
J J ASONDJFUAHJ J » S 0 N B
Figure V-5. Nitrate in Anderson-Cue and McCloud Lakes
35
30
JS
X
15
10
McOwd
\
A
A J J A 0 H B JfK.H *
IM7 1961
J F U *
J J *
0 N 0
Figure V-6. Ortho-Phosphate in Anderson-Cue and McCloud Lakes
-------
I
Ui
10
Figure V-7. Total Phosphate in Anderson-Cue and McCloud Lakes
-------
During the first 21 months of nutrient enrichment (through
December, 1968), approximately 217 kg nitrogen and 18.5 kg phosphorus,
mostly as ammonia and ortho-phosphates, were added to Anderson-Cue Lake
through the nucrient outfall. This was sufficient to increase the N
and P levels in the lake by 0.87 and 0.082 mg/1, respectively, at the
lake's volume in 1967, if all the nutrient material remained in the
lake. The actual nutrient increase should have been larger because of
the decrease in lake volume in 1968. Inspection of Figures V-3 to V-7
shows this theoretical situation clearly does not apply. Increases in
total N and P concentrations do not approach these levels and much of
the added nutrient evidently was deposited in the sediments or was lost
through ground water seepage. This has been found to be the case in
other lakes where nutrient budgets have been constricted. This would
seem to imply an important role for sediment regeneration of nutrients
in the eutrophication process. Possibly the onset of deleterious con-
ditions in the eutrophication process is contingent upon exhaustion of
the sediment's capacity to retain nutrients.
Considerably greater detail is known about the variations of
chemical species in the lakes than was presented above. The data in
Figures V-l to V-7 represent mean values for each lake on a particular
date. Data were collected from the three depths at each mid-lake sta-
tion on each date. Table V-3 summarizes results for some biogenic
elements at the three depths; the data indicate the lakes are well mixed
vertically (as implied by the temperature and dissolved oxygen data in
an earlier section), and the vertical differences in chemical species
were usually very small. Differences between the stations in each lake
are also small for most chemical species. Occasionally, parameters
such as total organic nitrogen have exhibited significantly higher values
at the shore stations, apparently because of slough-off from littoral
vegetation. Table V-4 is a summary of some data from the three stations
in Anderson-Cue Lake and the two stations in Me Cloud Lake. Because of
the large number of samples even the small differences shown for some
parameters are statistically significant, but it seems unlikely that the
differences would be ecologically significant or that they would change
one's opinion about the lakes1 homogeneity.
A detailed study of the lateral variations in ammonia and ortho-
phosphate was conducted in January, 1968, and gives further evidence of
the experimental lakes' comparative homogeneity. This is not to say
that there are no differences at all. Figure V-8 shows a slight trend
for higher ammonia near the southern shore. In general, ortho-phosphate
was higher in shore areas than in the lake center (Figure V-9), but
values for the southern shore were the lowest in the lake. The high
ortho-phosphate values in the northwest portion of the lake probably
represent a minor source of pollution from cattle grazing in this area
during this period. The results indicate that the routine stations are
representative of the conditions throughout the lakes within the limits
of accuracy desired for this project. A detailed survey of the area
surrounding the nutrient outfall was conducted in January, 1969. The
results shown in Figure V-10 imply rapid mixing in the lake since no
concentration gradients resulting from nutrient additions were found.
-33-
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TABLE V-3
COMPARISON OF AVERAGE CONCENTRATIONS OF SOME
BIOGENIC PARAMETERS AT THREE DEPTHS
IN STATIONS 7 AND 11.
Parameter* Station N*
pH
TOH
PON
HH3
O-P04
t-P04
7
11
7
11
7
11
7
11
7
11
7
11
19
10
19
10
18
10
18
10
11
9
11
9
20
10
20
10
21
10
21
10
18
9
18
9
Year
1967
1968
1967
1968
1967
1968
1967
1968
1967
1968
1967
1968
1967
1968
1967
1968
1967
1968
1967
1968
1967
1968
1967
1968
Top
Mean S.D.
4.67
5.20
4.90
4.97
0.41
0.33
0.40
0.30
0.15
0.17
0.14
0,17
0.104
0.363
0.052
0.136
4.0
11.5
3.9
7.5
9.3
24.6
7.7
10.6
0.50
0,49
1.12
0.31
0.15
0.06
0.19
0.06
0.08
0.05
0.23
0.06
0.057
0.199
0.033
0.083
4.6
8.8
5.8
5.4
9.9
29.0
8.8
6.1
Mid
Mean S.D.3
4
5
4
4
0
0
0
0
0
0
0
0
0
0
0
0
5
12
3
8
12
20
9
12
.75
.08
.75
.93
.49
.37
.43
.37
.23
.22
.19
.19
.126
.368
.060
.133
.5
.0
.3
.4
.8
.1
.7
.4
0.64
0.24
1.29
0.34
0,20
0.09
0.16
0.07
0.20
0.07
0.16
0.07
0.112
0.179
0.036
0.068
7.0
8.9
4.9
5.9
7.4
9.3
8.2
5.4
Bottom
Mean S.D. _
4.
5.
4.
4.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
6.
13.
3.
11.
11.
24.
13.
18.
74
27
70
92
65
38
50
38
35
21
26
21
102
393
093
179
1
4
1
9
1
0
4
1
0.72
0.35
1.25
0.48
0.48
0.09
0.22
0.11
0.45
0.08
0.27
0.10
0.069
0.191
0.077
0.097
8.2
11.3
5.0
12.7
8,2
7.4
9.5
15.7
Values for total organic nitrogen (TON), particulate organic nitrogen (PON) and
ammonia in mg N/l; ortho and total phosphate in yg' P/l.
^ "H * number of determinations. Data from 1968 are for January to October, while
data from 1967 are for entire, year.
S.D. standard deviation U (x-x)^. These are standard deviations of the results
I Ml
from the particular station and depth for the given year and reflect the annual
variability rather than the' analytical precision of the test. They are presented
primarily to indicate the former rather than for further statistical testing,
-34-
-------
TABLE V-4
COMPARISON OF AVERAGE CONCENTRATIONS OF SOME
BIOGENIC PARAMETERS AT THE
ROUTINE SAMPLING STATIONS
Anderson-Cue Lake McCloud Lake
Station Station Station Station Station
Parameter
PH
Acidity
TON
?N
NH3N
N03N
0-P04
t-P04
COD
BOD
Year
1967
1968
1969
1967
1968
1969
1967
1968
1969
1967
1968
1969
1967
1968
1969
1967
1968
1969
1967
1968
1969
1967
1968
1969
1968
1969
1967
1968
1969
4
4.70
5.10
4,80
3.5
2.8
3.5
0.54
0.39
0.35
0.38
0.21
0.22
0.101
0.356
0.190
0.043
0.097
0.075
3.9
12.1
4.3
11.7
24.2
19.4
8.4
5.64
0.86
1.14
0.74
7
4.72
5.18
4.83
3.6
3.0
3.3
0.52
0.36
0.29
0.24
0.20
0.18
0.111
0.374
0.215
0.040
0.090
0.078
5.2
12.3
2.6
11.1
22.8
16.4
9.7
5.64
0.89
0.80
0.38
8
4.76
5.15
4.77
3.3
2.9
2.9
0.62
0.59
0.27
0.37
0.24
0.16
0.112
0.337
0.198
0.041
0.088
0.079
4.2
13.3
2.9
11.6
22.8
19.3
20.7
3.76
1.83
1.33
0.19
11
4.78
4.94
4.98
4.1
3.3
2.9
0.44
0.35
0.34
0.20
0.19
0.13
0.068
0.149
0.070
0.024
0.058
0.022
3.7
9.2
3.7
10.3
13.7
15.0
11.4
5.64
0.96
0.58
0.48
12
4.64
5.03
4.98
3.1
2.6
2.4
0.48
0.49
0.39
0.26
0.29
0.22
0.064
0.121
0.074
0.019
0.064
0.025
2.9
7.6
3.1
9.2
15.3
20.0
8.5
3.76
0.73
1.54
0.16
^Acidity in mg/1 as CaCOs; ortho and total phosphate in yg P/l; all other values
in mg/1. PN stands for particulate organic nitrogen.
-35-
-------
figure V-B. Loftroi Verionons ot Amir.onio in Andeisoo-Cuo
Lcke, Jc/iucry, J9cS, Concentrations in rr-3 N/l.
Lccctions &f routine wmplinj stations shewn In
b!oc!cs.
Fl8«r» V-». LoUral Vcrictiow of Ort!-o-Fh«ishc!o In
Andcisc.n-Cuc Loli«, January, I*o3.
Concanffotiew In c« P/l, Lccotlon of
I«U»IM sampling itoliora shown In blocU
-36-
-------
u>
o '*-
Figure V-10. Ammonia and Phosphorus Concentrations
Around Nutrient Outfall January 1969.
-------
Several diurnal studies in which samples were taken every hour
or every two hours over a 24 hour period have also been made, but in most
cases the small variations appear random rather than cyclic. A few par-
ameters do show a measurable diurnal variation; Figure V-ll illustrates
this behavior for several biogenic species during a diurnal study from
January 31 to February 1, 1968. As Anderson-Cue Lake becomes further
enriched and more productive, biogenic species will undoubtedly show
greater diurnal periodicity, and studies of the lake's diurnal varia-
tions may be a useful indicator of the lake's advancing eutrophy.
Sediment Studies
Sediments may exert considerable influence on the eutrophication
process, both as nutrient sources and as nutrient sinks. Furthermore,
they can exert large oxygen demands on the overlying water and provide
a home and substrate for organisms which spend all or part of their life
cycles as benthos. A variety of studies has been undertaken to provide
a better understanding of the role of lake sediments in eutrophication.
As a first step, chemical characteristics and variations in
sediment types have been determined for the study lakes. Representative
results for Anderson-Cue Lake are shown in Figures V-12 through V-14.
Several sediment types occur in the lake: near shore, the bottom is
sand covered with a thin layer of loose detritus and periphyton. In
parts of the deep regions, peat-like sediments are evident with much
fibrous and undecomposed plant material. In other areas the sediments
are darker and finer grained, more like the ooze or sapropel of alka-
line lakes. The sediments of McCloud Lake have not been as well charac-
terized, but peat-like sediments are less in evidence there. The
results indicate that sediments from these lakes are actually higher in
nitrogen and phosphorus than sediments from some eutrophic lakes. For
example, sediments from Lake Mendota, Wisconsin, have from 200 to 1200
phosphorus and 2000 to 14,000 ppm total organic nitrogen (Hasler, 1963).
The sediments in this alkaline lake are over 30 percent precipitated
calcium carbonate, whereas those in the lakes of this study are composed
largely of organic matter. The absence of carbonate deposits in the
sediments of the study lakes permits volatile solids determinations to
approximate the organic content of these sediments. The high values
in Figure V-14 indicate the largely organic nature of these sediments.
The sediments in the study lakes are obviously enriched with
nitrogen and phosphorus compared to the overlying water and thus re-
present potential nutrient sources. However, most of the nitrogen is
present in the organic form rather than as free ammonia (Figure V-12),
and most of the phosphorus is also bound (presumably organic) rather
than free ortho-phosphate (Figure V-13). Leaching and incubation
studies undertaken to reveal the importance of sediments in nutrient
storage and release must consider the wide variations in available nu-
trient content of the various sediments in the lake as well as the
-38-
-------
w
vo
i
16.0 r
u
o
a.
v
15.0
14.0
4)
Vt ^"*
5(5
10.0
c co
O
2.0
1.0
"- U
o<
Temp.
0.5
- 0.25
o
a
'c
J L
_L
J L
J L
J_
J L
12N 4PM
Jan. 31
8PM
12M
Time
4AM SAM
Feb. 1
12N
Figure V-ll. Diurnal Variations in Anderson-Cue Lake.
-------
N
N
Figure V-12, Nitrorjcn in Anderson-Cue Scsli-Tcnts. Top
nuTtber is QT.frc.nta; l:o.Vm number is total
or.y!n!c nitro^n. Values in mg N/9 dry \vt
Figuro V-13. PliospMare in Anttcnon-Cjc Sadimcnn. Top
nuin'^or is oriho phosphoU, bollofl ntir.Uf it
total phcsphotc value! in /ifl P/g dry wt. of
sediments.
-40-
-------
N
Figure V-14. Percent Volatile Solids (Top Number) and
Tofal Iron (Bottom Number) In Anderson-Cue
Sediments. Iron values in mg Fe/a dry wt. of
sediment.
-41-
-------
varying opportunities for transport from sediment to water afforded at
different locations in the lake. For example, bottom currents are com-
paratively slow in the center or deep portions of the lakes and nutrient
exchange may be a diffusion-controlled phenomenon. On the other hand,
the thin sediment layer in the sandy littoral areas is frequently and
easily mixed with the overlying water by wind-generated currents and
waves and by movement of fish. Nutrient release from these sediments is
probably controlled by metabolic rates rather than by physical factors.
The overall question of nutrient exchange between sediments and water
(in either direction) is extremely complex and a completely satisfac-
tory answer is perhaps beyond the "present state of the art".
A variety of sediment exchange experiments, including laboratory
and in situ studies, have been undertaken or are presently underway or
planned. Some initial results of a laboratory incubation study are
shown in Figures V-15 and V-16. Sediment from the middle of Anderson-
Cue Lake was incubated in 10 liter bottles under varying conditions, and
ammonia and ortho-phosphate in the over-lying water was followed over a
period of 20 days. About 0.5 liters of sediment was placed in each
bottle. Incubation was conducted in the laboratory at 22°C under condi-
tions of (artificial) laboratory lighting. One bottle (A) was incubated
under the above conditions; a second bottle was treated similarly ex-
cept that light was excluded (C), a third bottle (B) was continuously
purged with nitrogen to maintain anoxic conditions and a fourth bottle
(D) was stirred to keep the sediment mixed with the water. Changes in
the ammonia content of the overlying water are shown in Figure V-15.
Anoxic conditions allowed more ammonia leaching in bottle (B) than in
the oxygenated control (A). However, stirring was more effective and
maximum ammonia was released immediately. A similar situation occurred
with ortho-phosphate (Figure V-16). Anoxia induced the release of
considerably more phosphate than oxygenated conditions in the control.
The dark bottle showed consistently lower ortho-phosphate than in the
control, but the trend was similar. Again mixing was most effective
in liberating phosphate. The maximum phosphate was released almost
immediately and the concentration declined about 50 percent over the 20
day incubation. It is obviously premature to extrapolate these results
to the in situ role of sediments in nutrient recycling. But it would
seem that mixing is the most effective mechanism to release sediment
nutrients into the water if that were desired. Alternately it is appar-
ent that the single most effective means of limiting release is preven-
tion of mixing. In deep lakes relatively little mixing occurs. However*
during periods of high winds, sufficient currents may be generated in
shallow lakes and littoral zones of deeper lakes to stir sediments with
the water and release considerable amounts of nutrients.
-42-
-------
.6
.5
.4
.3
D (xO.5)
10
15
20
Days
Figure V-15. Temporal Changes of Aqueous Ammonia In Lake Water
Incubated With Sediment Under Varying Conditions:
A, control; B, anoxic; C, dark; D, stirred.
20
Days
Figure V-16. Temporal Changes of Aqueous Ortho-Phosphate in
Lake Water Incubated With Sediment Under Varying
Conditions (see Figure V-15 for key).
-43-
-------
SECTION VI
BIOLOGY
Introduction
Biological studies of Anderson-Cue and McCloud Lakes have
included: (1) the species, succession and productivity of algal forms,
(2) the standing stock of phytoplankton, (3) limiting nutrients for
phytoplankton growth, (4) standing crop estimates of littoral vegetation,
and (5) production estimates of the zooplanktivorous fish Labidesthes
sicculus. In addition monthly diurnal variations in primary productivity
have been noted along with plant pigment levels as a measure of algal
biomass. Two special 10 day studies dealt with an analysis of environ-
mental factors affecting primary production (Brezonik e_t ad, 1969). The
methods for these procedures are outlined in Appendix B.
Methods Developed
Except for the special techniques described below, all biological
observations in this study were carried out using standardized tech-
niques such as outlined in Standard Methods for the Examination of Water
and Wastewater (1965) and FWQA Analytical Techniques for the National
Eutrophication Research Program (June, 1969). Special techniques to
determine population dynamics and productivity of zooplankton were de-
veloped and are described below.
Zooplankton samples were taken from January, 1967 through
December, 1968, in Lake Anderson-Cue and from May, 1967, through
December, 1968, in Lake McCloud. From January to August, 1967, samples
were taken bi-weekly with a Wisconsin closing plankton net (125 meshes/
inch) towed horizontally for a known distance at three depths corres-
ponding to just below the surface, mid-depth, and just above the bottom.
Aliquots from these samples were counted; counts were adjusted to
No./m3 and integrated over depth to obtain No./mz. After August, 1967,
weekly samples were taken with a vertical-tow plankton net (125 meshes/
inch) pulled from bottom to surface. When using the vertical-tow net,
samples were taken from three stations in the lake and each sample con-
centrated to 35 ml. The three samples were combined, mixed thoroughly,
and a sub-sample of 35 ml taken from the mixture for preservation with
formalin and for counting. This procedure provided a physical means
of averaging samples from three areas of the lake while counting only
one sample, thus providing a more representative sample from the lake.
-------
Zooplankters were counted using a compound microscope at a
magnification of 21 diameters. Each sample was shaken thoroughly; a 1 ml
aliquot was then taken with a graduated syringe and placed in a Sedge-
wick-Rafter counting chamber. Three such aliquots were counted for each
sample and all zooplankters in the chambers were identified and counted.
Occasionally, when phytoplankton was especially numerous, it was neces-
sary to dilute a sample before counting. Counts from samples taken with
a vertical-tow net were converted directly to No./m2 based on the area of
the net mouth; e.g., a net with a 0.2m2 mouth area towed from bottom to
surface would collect the plankton under 0.2m2 of lake surface.
Biomass determination. To determine the mean individual biomass
of a zooplankton species, individuals were sorted from a sample under a
dissecting microscope, blotted, dried under vacuum desiccation, and
weighed on a calibrated quartz helix. From 5 to 200 dry individuals
were weighed at a time to get an adequate deflection of the helix. To
avoid bias in unconsciously selecting only the larger individuals,
several drops of plankton sample were placed on a watch glass and all
individuals of a species were removed for drying. The total indivi-
duals weighed of any species were taken from several samples in case a
species might average larger in some samples than in others. Due to the
small size and relative scarcity of planktonic rotifers in these lakes,
only the biomass of the most abundant species, Keratella americana,
could be determined. For conversion of population estimates to biomass,
all other rotifers were considered to be the same size as K. americana.
The obvious error involved is quite small in terms of total zooplankton
biomass since K. americana, when abundant, comprised only ca. 7 percent
of the total biomass.
After the mean dry weight/individual of a species had been
determined, the species biomass for any sample date was calculated by
multiplying individuals/m2 by rag/individual. The species biomasses
were summed to obtain total zooplankton biomass.
Secondary production. An estimate of yearly production was made
for each zooplankton species except that rotifers other than K. americana.
were lumped. In order to put limits on secondary production, three
calculations were made: a minimum estimate, a maximum estimate, and a
"best estimate". The minimum estimate for a species was obtained by
summing the net positive change in population size over a year, then
multiplying by the average mass per individual of the species. The
other two estimates were unrelated to the minimum estimate, except that
all were based on the same population data and biomass data.
The classical sigmoid growth curve for a population is described
dN _ rN(K-E
dt K
by the equation
-------
N = No. of individuals
t = time
r = instantaneous rate of increase
K = carrying capacity of the environment.
If N is very small relative to K the expression K-N simplifies to 1.0
K
and the resulting equation, dN = rN describes the logarithmic phase of
dt
the growth curve. In this study N was considered to be very much smaller
than K for several reasons :
1. The relative density of zooplankton in oligotrophic lakes
such as those studied is very low. For example, maximum
cladoceran densities in Anderson-Cue and McCloud are in the
order of 50-100/liter. Ward (1940) reported up to 2,000
cladocera/1 in a small pond and Borecky (1956) reported
3,500 cladocera/1 in Pymatuning Reservoir.
2. Density dependent effects on laboratory populations of
Daphnia were not seen by Frank, e_t a_l (1957) until densi-
ties of 1,000-2,000/1 were reached.
3. A plot of r vs. N for data from Anderson-Cue shows no ten-
dency for r to decline as N gets larger. If N were approach-
ing K, r should be approaching zero.
The equation dN = rN can be written in its integrated form:
dt
T" t"
Nj- * Noe , and taking natural logarithms: In Nt = rt + In No,
which when In Nt is plotted against t, gives a straight line with r as
the s lope .
In this study logarithms of population were plotted against time
and each slope was considered to be an estimate of r over that time
period. For any species the maximum positive slope observed was con-
sidered to approximate rm, the intrinsic rate of increase for that
species. To determine maximum production, each species was considered
to be reproducing at rm at all times during the year so that observed
differences between r and rm were considered to be due entirely to a
variable death rate. The maximum productivity at any time was calculated
from the equation:
Pm=Nt rm B'
n = maximum productivity
Km
N = population size at time t
-------
r = maximum observed instantaneous rate of increase
m
B = average biomass per individual .
Values of Pm were integrated over a year's time to get maximum yearly
production.
The "best estimate" of production was determined similarly to
maximum production except that all positive r values were used to de-
termine productivity: p = N r B, where:
N and B are the same as above
r = the observed rate of increase at time t
p = productivity
Productivity was integrated over time to get a "best estimate" for
yearly production. Finally production values for all species were
summed to get total zooplankton production.
Fredaticm. Labidesthes sicculus was considered to be the chief
zooplankton predator in these lakes. The population size of Ij. sicculus
was estimated using the Peterson mark-recapture method as described by
Ricker (1958). Fish were captured individually at night with dipnets
and each fish was immediately marked by clipping a pectoral fin and
released. Since L. sicculus will lie at the surface in shallow water
on a dark night, the marking procedure was fairly simple. The brief
period of handling ensured minimum damage to the fish. Recaptures were
made after one week.
At numerous times during the year, samples of _L. sicculus were
collected with a dipnet or seine and preserved in 10 percent formalin
for later analysis. To determine food habits, each fish was measured
and its gut contents analyzed. The entire gut was removed, carefully
pulled apart, and washed with a few drops of water in a Sedgewick-Rafter
counting chamber. All recognizable organisms in the gut were counted
under 21X magnification with frequent use of higher magnification to
check identification. The counts of zooplankton in the gut were con-
verted to total mass of zooplankton eaten by multiplying the number of
each species by the mean individual biomass for the species.
Statistics. Statistical tests were used to evaluate apparent
trends in the results. Since sampling frequency was arbitrarily chosen,
samples were considered to be random with respect to population sizes
or biomass. Total biomass values were assumed to have an approximately
normal distribution. In determining correlation coefficients between
species, only samples in which both species occurred were used, as in-
-48-
-------
elusion of zero values would constitute a significant departure from a
normal distribution and thus invalidate the test statistic "r". All
statistical tests used are described by Mendenhall (1967). A signifi-
cance level of 0.05 was used throughout.
In a related, but independent study, the interactions of littoral
zooplankton and their fish predators were studied. The analysis scheme
used in this study is described below.
Zooplankton collections were made in each lake every two weeks.
Samples were taken in the inner zone (water depth = 0.5-1.0m) with a
Van Dorn water sampler (volume = 1.93 1) after vigorous stirring to
dislodge organisms from the vegetation and insure random dispersal in
the water column. These were concentrated to 32 ml with a plankton net
and preserved in one percent formalin. Three one ml aliquots were
counted. All cladocera were identified to species. Rotifers were iden-
tified to genera. Copepoda and their nauplii were counted, but not
identified. Counts were converted to organisms per m2 by multiplying
the organisms per m by depth (m) at the sampling site.
Etheostoma fus 1forme and Heterandria formosa were collected every
two weeks with a dipnet in the same area as the plankton sample. Five
fish of each species were taken from each lake and preserved in 10 per-
cent formalin. Due to the small size of the fishes and the lack of a
definitive stomach in H. formosa, the entire gut contents were removed
and counted. Although total length of each fish examined was recorded,
all sizes of both species of fishes fed on the same organisms.
The contribution of each species or group of zooplankters to the
diet was expressed as its percentage of the total organisms eaten. Due
to the large number of species and the difficulty in measuring the bio-
mass of individual zooplankters, the contribution of species or groups
in terms of proportion of total biomass was not determined. Bi-weekly
fish gut analyses were pooled and reported as monthly averages.
During the second year of the study, fish densities were estimated
by pulling a wire mesh dredge through specified areas in the littoral
at various times during the year.
Gut clearance rate. Laboratory experiments were conducted to
determine gut clearance time at 15°C, 20°C, and 30°C for both fishes.
Following two weeks of acclimation fish were placed in a feeding cham-
ber containing zooplankton. After 30 minutes they were returned to
their original aquaria. At intervals of 1 or 1/2 hour, five fish were
removed and their gut contents were examined, until the microorganisms
were in the lower portion of the gut and were no longer identifiable.
-------
Algal succession. The variety and succession of algal forms have
been followed both along the marginal shallow bottom and among the lit-
toral vegetation of both lakes. Comparisons have been made with the kinds
and numbers in the open surface water and with those close to the water-
sediment interface at maximum depth. This early work which began in 1965
was reported previously (Lackey and Lackey, 1967) and serves as a base-
line for future changes in the microbiota as nutrient enrichment con-
tinues.
Both lakes are similar in many respects. For example Synura
uvella occurs in both lakes and typically is more abundant in the deep
open water areas. Many species of colorless Euglenophyceae are found
in the lakes and each body of water supports a bloom of Dinobryon at
least once during the late winter. Both support a varied dinoflagellate
flora. Generally the low population of photosynthetic forms indicates
limited algal growth substances and the low numbers of zooflagellata and
ciliates as well as the paucity of open water euglenids indicates the
low organic content of the lake waters.
As the experimental lake continues to eutrophy the greatest
fluctuation in species will be those which occur in very small numbers.
A question to be answered is whether the crop of Dinobryon, Synura,
Peridinium umbonatum and Stentor amethystinus will increase considerably
as enrichment proceeds or whether species now encountered infrequently
will increase and supplant the present common organisms.
Rhode as discussed in Hutchinson (1967 ) has reported the
disappearance of Dinobryon with increasing phosphorus levels. It will
be interesting to note the effect of rising phosphorus levels in
Anderson-Cue Lake on the indigenous Dj.nobryon. population. Blooms of
these chrysophytes occur annually between December and February. Data
for plankton analysis are presented in the Appendix. A summary of this
phase of the research showing the number of species and frequency of
occurrence is outlined in Table VI-1. Generally the total species of
each lake is similar. This is so because nutrients have been added so
that biotic changes can occur gradually and it is still early to note
marked differences. Some species variation obviously does exist be-
tween the two lakes, but presently we can not determine whether this is
a reflection of nutrient enrichment. The plankton data as presented
should be considered as representative for the soft, acid, sand bottom
lakes found in north central Florida.
Appendix C reflects the percent occurrence of species during
1967 and 1968. The data are qualitative since population and biomass
estimates were infrequently carried out. The extensive list of species
includes littoral as well as open water forms and therefore forms not
usually associated with the open water plankton are included. A great
many inshore forms are part of the periphyton. This community although
an important part of the lake biota, often is not considered in limno-
logical investigations. However, the periphyton can be the most pro-
ductive plant community in a lake system as was observed by Wetzel
(1962) in the study of Borax lake in California.
-50-
-------
TABLE VI-1
GROUPS OF MICROSCOPIC ALGAE AND PROTOZOA IN DETAILED ANALYSES
ON FIVE DATES IN 1967-68 IN McCLOUD AND ANDERSON-CUE LAKES,
AND THH NUMBER OF OCCURRENCES.
Organism Group
Sulfur Bacteria
Blue Green Algae
Green Algae
Volvocales
Euglenophyceae
Cryptophyceae
Chrysophyceae
Chloromonadida
Dinoflagellata
Bacillarieae (Diatoms)
Rhizopoda
Zooflagellata
Ciliata
Torals
Total
Soecies
2
26
58
7
39
5
23
4
17
7
31
22
59
300
McCloud Anderson-Cue
No.
Species
1
24
48
7
23
5
23
2
17
5
21
18
42
236
No.
Occur.
3
23
117
13
40
18
33
6
36
8
40
23
82
472
No.
Species
2
21
39
2
29
5
18
4
14
4
24
15
41
218
No.
Occur.
4
33
101
5
50
14
24
8
31
6
33
19
82
410
-------
Effect of Nutrient Enrichment
Anderson-Cue has been enriched with nutrients since March, 1967.
The 34 month regimen included loading with 300 gallons of secondary sew-
age effluent with supplemental nitrogen and phosphorus to achieve 2.48 kg
N and .212 kg P weekly. As of August, 1970, approximately 387 kg N and
33.00 kg P have been added. Lake response during this time has been
negligible for most of the routine chemical and biological parameters.
Table VI-2 shows yearly averages for some biogenic parameters in both
lakes for the period 1967-1969. A mean for February and April 1970, is
also included. As the data show, using the mean for all years, a sig-
nificant difference does occur for chlorophyll a_, but among no other
parameters. However, averages for individual years relate increased
ammonia and primary production as well as plant pigments as response
parameters.
Figure VI-1 and Table VI-3 A,B summarize phytoplankton production
levels for a three year period beginning in 1967. The curves for the
two lakes with regard to their productivityapproximate one another
rather closely showing a similar summerearly fall maximum. Annual
production estimates in Anderson-Cue Lake show essentially no differences
with Lake McCloud. The level of fixed carbon at the end of 1969 was
58 grams/m for Anderson-Cue compared to 60 grams for the control lake.
Bioassays using C1^ techniques as well as Provisional Algal Assay Pro-
cedures (PAAPl show phosphorus to be a principle limiting nutrient in
both lakes.
Certain comparisons can be made with other nearby lakes in
Alachua County which demonstrate eutrophic conditions. Productivity
determinations were made on these lakes in November, 1968, using an en-
closed box with a constant light source at an ambient temperature of 20°C.
Hawthorne 55.45*
Newnan's 53.55
Bivens Arm 77.54
Orange 43.01
Wauberg 124.30
McCloud 21.83
Anderson-Cue 11.52
3
*mg C fixed/m -hour
These data indicate that both lakes in the experimental system
are less productive and that Anderson-Cue will require much more nu-
trient enrichment to reach a level comparable to other eutrophic lakes
in this area. Interestingly enough comparative productivity of Lake
Apopka and Lake Dora in Orange and Lake Counties which are recognized
hypereutrophic lakes in central Florida is 400 mg/c3-hr and 1000 mg C/nr*-
hr respectively. Both of these lakes support continuous algal blooms
throughout the year. In addition the lakes are virtually useless for
recreational purposes.
-52-
-------
TABLE VI-2
COMPARISON OF AVERAGE CONCENTRATIONS OF SOME
BIOGENIC PARAMETERS IN EXPERIMENTAL LAKES 1968-1970
Anderson-Cue McCloud
Parameter Year
PH
Conda
TON
NH3-N
N03-N
PO^-P
Total P
PPb
Chi ac
1967
1968
1969*
1970
1967
1968
1969
1970*
1967
1968
1969
1970*
1967
1968
1969
1970*
1967
1968
1969
1970*
1967
1968
1969
1970*
1967
1968
1969*
1970
1967
1968
1969
1970*
1967
1968
1969*
1970
Annual <,
.30 '36
.23
.11
39 1R
.20 l18
.02
.04
.08 0?
.10 '°7
.07
.005
:S5
.002
.011
.026 Q1,
.017 'QU
.020
92.43
157'44 134 83
154.61 134'83
2.04
?:S
2.15
4.75
5.03
4.89
5.42
_.
38.15
35.00
34.50
.45
.34
.32
.26
.07
.11
.06
.26
.02
.04
.02
.02
.004
.011
.003
.001
.010
.014
.017
.015
107.18
140.08
152.79
1.63
1.30
2.43
2.41
5.02
35.88
.34
.12
.02
.005
.014
133.35
1.94
average of February and April
apnho cm'
b 2
primary production mgc/m -day
Cchlorophyll a mg/m
-53-
-------
Figure VI-1
E
i
>>
o
Q
O
9
£
o
O
O
o>
E
o
Q
K
iZ
o
9
500
400
300
200
100
0
f
700
600
500
4OO
300
200
100
0
1968
Anderson-Cue
McCloud
1969
Anderson-Cu«
,' , McCloud
A
I 2 34 56 7 8 9 10 II 12
Month
ANNUAL VARIATION OF PRIMARY PRODUCTIVITY IN
ANDERSON-CUE AND WcCLOUD LAKES
-------
TABLE VI-3 A
PRIMA1W PRODUCTIVITY VALUES FOR ANDKRSON-CUE LAKE
Dale
nig C fixed/day
Surface 5'
10'
mg C fixed/day
1/24/67
1/31/67
2/28/67
3/14/67
3/28/67
4/11/67
4/25/67
5/9/67
5/23/67
6/6/67
6/20/67
7/7/67
7/19/67
8/1/67
9/12/67
9/26/67
10/11/67
11/28/67
1/9/67
2/21/68
3/19/68
4/29/68
5/16/68
6/18/68
7/23/68
8/27/68
9/16/68
10/14/68
11/11/68
12/11/68
1/6/69
2/3/69
3/14/69
3/31/69*
4/28/69
5/26/69
6/23/69''=
7/23/69
8/18/69
9/15/69
10/21/69
11/18/69*
12/15/69
1/14/70
1967 Avt!ra£O
1968 Average
1969 Average.
7.18
2.30
19.70
20.80
7.47
34.80
47.30
9.53
28,90
31.60
68.40
96.00
127.50
33.80
40.10
31.90
22.70
17.00
17.40
33.10
26.70*'
35.91
105.63
153.34
113.16
128.52
160,90
151.08
16.29
15.64
40.40
108.65
20.39
28.20
32.19
64.40
274.31
157.32
161.73
64.10
12.17
8.43
1.12
14.74
9.21
9.39
9.23
6.24
14.60
25.60
32.40
14.00
27.50
27.20
47.70
57.50
98.10
66.70
14.40
15.04
51.30
21.70
18.40
31 . 80
15 . 52*
34.45'
59.60
72.01
107.36
41.76
140.90
83.88
13.61
18.19
73.30
113.51
22 . 32
34.43
14.76
74.95
226.97
43.06
27.00
40.38
7.21
11.91
1.22
14.95
12.30
9.70
6.91
13.24
5.90
21.80
22.00
7.33
8.62
23.70
10.30
42.80
70.30
33.50
6.80
35.60
43.50
15.80
6.93
48.50
4.47*
1.40
9 . 32
6. /b
5.66
9.70
8.62
11 ! 76
4.18
16.25
17.06
37.68
9.06
9.64
1.33
1.39
41.16
20.98
8.90
7.04
2.93
11.91
0.92
5.50
^ f^y-* * *"
29 . 84
26.44
32.56
27.28
38.40
81.40
100.80
37.60
75.60
84 . 00
138.80
185.20
303.20
183.60
53.60
62.60
141.60
61.20
50.20
101.00
48.20
90.00
181.60
2e0.80
294.00
152.00
397.00
252 .50
39.00
53.00
181.40
308.40
60.30
93.10
46.20
191.20
635.00
182.50
137.50
116.00
21.68
33.00
3.45
37.32
92.43
157.44
154.61
jj ciii j^x \-y p / t.
402
382
J\Jt*
375
203
ft\J J
540
652
703
400
461
483
456
607
504
225
560
573
f* / *J
461
294
42'»
t,'J'i
K "> /
*-* : "! *
6f:0
56t
560
580
380
476
110
315
300
215
392
490
573
358
556
522
606
266
221
340
361
212
*Valucs were obtained from diurnal data, calculated by
incubation periods at each depth and multiplying by hours of
daylight. '
-55-
-------
TABLK VI-3 B
PMIJAUY rr.OnUCl'IVlTY VALUES 1-OK McCLOUD LAKE
mg C fixed/dayra^ mg C fixed/day
Pate Surface; V 10_V Rci?L
2/7/67
2/3.4/67
2/20/67
3/14/67
3/28/67
4/13/67
4/25/67
5/9/67
5/23/67
6/6/67
6/20/67
7/7/67
8/1/67
8/29/67
9/12/67
9/26/67
1/9/68
2/22/68
3/19/68
4/29/68
6/18/68
7/?Vf.8
8/27/68
9/16/68
10/14/68
11/11/68
12/11/68
1/6/69
2/3/69
3/14/69
3/ 31/69 *
4/28/69
5/7.6/69
6/23/69
7/23/69
8/18/69
9/15/6?
10/21/69
11/18/69*
12/15/69
1/14/70
1967 Average
1968 Average
1961) Average
8.28
3.27
13.80
5.21
24.92
24.90
2.00
10.50
30.86
59.50
59.56
32.69
68.03
6.49
53.78
109 . 59
7.70
2.10
3.14'=
23.14
99.12
76,73
282.26
142.10
57.48
23.48
10.99
5.63
15.66
5.87
4.17
26.47
47.47
139.26
231.29
198.21
9.76
20.06
6.53
2.35
6.44
15.50
3.53
13.90
16.34
13.64
30.16
13.26
17.34
31.33
43.72
96.23
49.90
45.48
14.43
29.33
150.57
18.44
5.60
3.99*
22.21
61.56
54.92
138.48
113.12
47,16
24.98
11.04
6.58
12.20
4.98
5.28
38.70
43.58
117.69
251.85
144.61
9.14
17.58
3.37
1.43
7.58
7.14
3.77
7.07
13,17
36.62
23.33
6.37
23.58
22.44
67.20
169.06
37.00
19.07
7.55
13.21
37.41
15.10
4.81
3.35*
15.30
28.38
32.98
64.78
69.35
30.00
12.01
8.18
5.55
8.53
5.44
4.82
29.92
46.50
75.35
277.10
86.53
4.20
9.35
3.37
3.47
7.16
41.10
10.72
39.36
39.20
55.00
87.30
33.28
52.80
92.00
151.80
312.00
139.00
137.00
37.64
94.60
392.00
50.40
15.64
11.54
64.20
192.00
J68.80
460.00
337.00
139.00
70.30
32.00
18.60
37.50
15.40
15.38
98.00
136.40
353.00
778.00
440.50
25.76
48.44
12.56
6.70
21.64
107.3.8
140.08
152.79
278
452
375
203
540
652
703
400
461
483
456
504
575
225
560
294
320
499
574
560
560
580
380
476
110
335
300
215
392
490
573
358
556
522
606
266
221
340
361
212
*Valnes were obtained from diurnal data, calculated by averaging
incubation periods at. each depth and multiplying by hours of day-
-56-
-------
The comparative production estimates of lakes provide information
regarding the trophic status which in turn can be useful in establishing
recreational and use potential of surface water. This technique is es-
pecially worthwhile in multi-lake studies where surface waters are being
examined on a regional basis. In this kind of investigation comparative
productivity estimates can quickly determine lakes where algal growth is
high and where ecosystem management procedures could be used effectively.
Diurnal variations in integral photosynthesis were recorded
monthly during 1968. These data are presented in Figure VI-2. (Hori-
zontal lines indicate rain.) Rather obviously marked variations in
integral photosynthesis occurred during 1968 in both lakes. Maximum
productivity in Anderson-Cue Lake was noted in September when fixation
of carbon amounted to 65 mg/m^-hr. Highest photosynthesis between the
two lakes was observed in McCloud. Fixation rates here reached 80 mg
C/m^-hr.at the end of August.
Variations in the vertical distribution of chlorophyll a_ between
McCloud and Anderson-Cue Lakes are presented in Table VI-4 and Figure
VI-3. The data are inclusive beginning in January of 1967. Generally
the mean value for chlorophyll a at the surface, 5 and 10 foot depths in
Anderson-Cue Lake (1.99, 2.00, 2.12 mg/nr) were comparable to McCloud
Lake (1.53, 1.89, 1.46 mg/m3) during the first year. The standing crop
of phytoplankton increased significantly during 1968 in Anderson-Cue
water, but remained virtually the same as before in McCloud. Average
values of 4.12, 4.12, and 4.41 mg chl a per m3 were noted in Anderson-
Cue Lake at the three depths while McCloud Lake supported an average
of 2.14, 2.02, and 2.24 mg chl a per m3.
Considering seasonal effects and based on integral values
chlorophyll a during 1967 gradually increased from a range of 1-5 mg/m
during the first four months to levels greater than 15 mg/m^ in Anderson-
Cue during mid-summer and fall, (Figure VI-3). Both lakes had approxi-
mately the same phytoplankton biomass based on pigment analyses except
for peaks during July and October in Anderson-Cue Lake. At these times
chlorophyll in the experimental lake reached a maximum in excess of 15
mg chl a_ per m^.
The 1968 data show the divergent characteristics of the two
lakes with regard to pigment levels. Chlorophyll a_ was 5 mg/m^ or
higher at all times during the year. Three peaks were evident. The
highest (>25 mg/m^) occurred in February during a winter flowering of
Dinobryon. The others as indicated in Figure VI-3 were observed in May
and late July. The spring bloom coincided with growths of Synura.
It is worthwhile noting the significant algal growth response to
added nutrients as evidenced in the elevated chlorophyll values. Most
frequently chlorophyll a was greater than 10 mg/m^. These data support
productivity data in that these two parameters show the response to nu-
trient influx far more rapidly than changes in species diversity.
-57-
-------
I 15
.* 10
u
o>
1/23
244 Lang leys
_L
_L
0800 1000 1200 1400 1600
2/27
15
10
5
0
449 Lang leys
0900 1100 1300 1500 1700
CM
e 4
U
,&
0
3/19
15 -
499 Langleys
10
5
^ o
_L
_L
_L
0900 1100 1300 1500 1700 1900
Time EST
4/29
1000 1200 1400 1600 1800
Time EST
EST Eastern Standard Time
EOT Eastern Daylight Time
Anderson-Cue
McCloud
- Clear
- Overcast
Figure VI-2. Diurnal Variations in Primary Production During 1968.
-58.
-------
f
L 30
TJ
V
£ 20
u
O>
E 10
5/16
0 - 600 Lang leys
I I
I I
0900 1100 1300 1500 1700
6/18
1000 1200 1400 1600 1800
40
's
I 30
£ 20
u
7/23
560 Lang leys
80
60
40
20
0900 1100 1300 1500 1700 1900
Time EOT
8/27
0900 1100 1300 1500 1700 1900
Time EOT
Figure VI-2. (Continued)
-59-
-------
60
50
U
en
30
20
10
9/16
40
30
20
10
0
0900 1100 1300 1500 1700 1900
TlmeEDT
10/14
476 Langleys
0900 1100 1300 1500 1700 190
Time EOT
u
o>
11/11
110 Langleys
I
0800 1000 1200 1400 1600
Time EST
12/11
315 Langleys
0900 1100 1300 1500 1700
Time EST
Figure VI-2. (Continued)
.60.
-------
Date
TABLE VI-4
CHLOROPHYLL a LEVELS
IN ANDERSON-CUE AND McCLOUD LAKES
Anderson-Cue
Surf 5'
10'
McCloud
Surf 5' 10'
1/17/67
1/24/67
1/31/67
2/7/67
2/14/67
2/28/67
3/14/67
3/28/67
4/11/67
ft/25/67
5/9/67
5/23/67
6/6/67
6/20/67
7/7/67
7/19/67
8/1/67
8/29/67
9/12/67
9/26/67
10/11/67
1/9/68
2/21/68
3/19/68*
4/29/68*.
5/16/68*
6/18/68*
7/23/68*
8/27/68*
9/16/68*
10/14/68*
11/11/68*
12/11/68*
1/6/69
2/3/69
3/14/69
3/31/69*
4/28/69
5/26/69
6/23/69*
7/23/69
8/19/69
9/15/69
10/21/69
11/18/69*
12/15/69
1967 Average
1968 Average
1969 Average
1.09
1.08
1.09
0.54
0.83
0.25
1.38
2.44
1.77
2.91
1.92
1.76
2.03
2.86
4.20
1.70
3.15
3.02
4.22
1.64
2.57
7.74
3.00
4.62
5.07
3.57
5.50
4.60
4.18
4.56
2.07
1.92
6.74
3.82
1.80
1.10
4.44
4.36
4.45
4.66
5.17
3.75
1.84
1.88
1.88
0.54
0.25
1.38
1.12
1.12
1.38
1.38
1.10
1.67
2.57
1.83
1.87
1.45
1.02
5.73
1.45
4.22
2.80
4.45
2.77
0.77
8.77
3.75
3.27
5.06
3.24
7.13
4.66
4.05
4.95
1.90
1.92
7.74
3.82
1.40
3.71
4.39
5.18
4.24
5.56
3.75
1.65
2.02
2.25
2.04
5.17
7.35
0.83
0.25
1.12
1.12
_
1.08
1.60
1.37
1.34
1.57
2.55
1.67
1.97
1.89
2.03
5.64
1.36
2.57
2.80
7.14
2.55
4.47
8.41
5.42
2.56
4.06
3.70
6.97
3.73
4.39
5.50
1,87
1.85
6.08
4.02
1.29
3.35
5.45
5.41
9.19
6.67
4.70
1.65
2.15
3.28
2
- rn
0.54
0.54
0.67
0.80
1.60
0.66
1.55
2.43
2.48
1.97
1.78
1.47
2.38
0.33
1.48
3.15
2.20
1.23
0.77
0.68
0.91
__
1.77
2.18
5.66
2.62
2.47
3.30
1.98
0.72
1.18
0.60
0.51
2.10
1.86
4.37
6.24
4.71
1.88
2.11
1.54
0.96
0.25
0.54
0.83
1.84
1.34
0.99
0.99
1.90'
3.18
1.96
1.98
2.03
2.70
2.57
3.39
3.41
2.20
_
0.10
1.12
0.73
0.84
____.
1.68
2.17
5.30
2.33
2.82
3.02
2.07
0.74
0.94
0.48
2.02
1.73
4.01
6.24
4.32
1.44
2.25
1.33
1.03
1.63
1.30
2.43
_ .
0.25
0.83
0.80
1.08
0.54
.
0.57
1112
1.90
2.56
1.86
2.32
0.68
1.49
1.59
2.48
2.81
1.99
_
__
1.12
0.86
1.01
_ ...
1.93
2.34
4.81
2.60
2.69
2.85
2.14
0.97
0.75
_
0.40
2.03
2.19
4.73
6.56
5.02
1.77
2.10
1.22
0.90
4.VW? .'VVtSJLelJJ« : r " -"* " "-*
*Diurnals - Chlorophyll a values are an average of approxiaately 4 samples
per day
-61.
-------
Figure VI-3
N_
25
20
15
10
5
0
1967
Anderson-Cue
McCloud
1968
25
20
15
10
5
0
Anderson-Cue
McCloud
«x
9
20
15
10
1969
Anderson-Cue
McCloud
J L
" I 2 3 4 5 6 7 8 9 10 II 12
Month
ANNUAL VARIATION OF CHLOROPHYLL a. IN ANDERSON-CUE
AND McCLOUD LAKES
-6?..
-------
McCloud Lake during the last half of 1968 had an increased
phytoplankton biomass reaching a peak in late August. During the last
two years the control lake always supported a maximum population of
phytoplankton during August and September.
Horizontal chlorophyll a distribution in Anderson-Cue Lake was
determined four times in 1968 from February to the end of May. These
measurements were made only in surface water. No correlative production
estimates were completed. As indicated in Figure VI-4 phytoplankton
was unevenly distributed in surface water on all sampling periods.
Chlorophyll a levels were always highest in the near-shore environment
ranging from 6 to greater than 15 mg/m . On three occasions these
occurred in the same extreme southern part of the lake. Causes for the
plankton patchiness are likely a combination of wind effects and local
areas of enrichment especially in the shallow water where animals visit
for drinking. Two experiments for coliform distribution confirmed
animal movement in the shallow water along the lake margin.
Limiting nutrients for phytoplankton growth were determined
essentially using Goldman's technique (1964, 1965) for bioassay. Many
results using this method are varied and interpretation is difficult
to make. Generally three qualitative judgements can be made. A parti-
cular substance may be limiting to plant growth, result in no change
or elicit an inhibitory response. The results of these bioassays are
shown in Table VI-5. Considering Anderson-Cue Lake, phosphorus limited
primary production 92 percent of the time during 1967 trials. The
phytoplankton did not respond to nitrogen additions indicating that this
substance was not a limiting growth factor,
Verification of the nitrogen experiments has been carried out
using a laboratory technique proposed by Fitzgerald (1968). The pro-
cedure essentially employs an exposure of ammonia nitrogen to a popula-
tion of organisms and ammonia uptake is followed over a set time period.
The results from this procedure (Table VI-6) showed that the natural
plankton from Anderson-Cue lake were not nitrogen deficient. These
data reflect the rising ammonia levels in the experimental lake as nu-
trient enrichment progresses (see Section V).
The reasons why phosphorus concentrations in the water do not
reflect those added to the lake are obscure. Certainly the supply is
insufficient for the optimum growth of much of the phytoplankton.
Phosphorus loss may be to the sediments although we have been unable to
determine this as yet.
Substances other than N and P appear to be limiting during
various times of the year. However, the difficulties encountered with
this particular method make refined judgements questionable. A reliable
standardized algal growth potential procedure is badly needed at this
time for all those doing eutrophication research.
-63-
-------
2/15/68
HH! >lOmg/M3
| 1 5-10ma/M3
3/1V68
>10.6mg/M3
9.5-10.5mg/M3
| | 8.1-9.
7.0-8.
4/9/68
>l5mg/M3
10.1-15mg/M3
[ I 4.1-10mg/M3
0-4ma/M3
4.5-6.2mg/M3
3-4.5mg/M3
Figure VI-4. Horizontal Distribution of Chlorophyll a
Ande r s on-Cue Lake.
-------
TABLE VI-5
ALGAL GROWTH RESPONSE TO NUTRIENTS
Anderson-Cue Lake 1967
1/4 1/24 3/14 3/28 4/11 5/23 6/6
N---XX--
P + + + - + + +
N,P + +
Fe X + X X X
Si X + X
S - X
Vitamins - - -
Trace
Metals - XX X
EDTA X - X
McCloud Lake 1967
2/14 3/14 3/28 4/11 6/6 6/20 8/1
N -X
P +XXX-- +
N,P + X +
Fe . + _ + ___
Si + + - + - X
S - + + + --X
Vitamins - X
Trace
Metals + + - - + - X
EDTA + - + + X X
+ = Limiting X Inhibitory
6/20 8/1 8/29 9/12
X X
XXX
X
8/29 9/12
+
X X
+
+ +
+ +
+ +
+
- «= No Change
-65-
-------
TABLE VI-6
AMMONIA UPTAKE BY ALGAE IN ANDERSON-CUE WATER
, Filamentous _
Time (min.) Chlorella Chlorophyceae
* *
0 1.24 0.83
+15 1.30 0.81
+30 1.35 0.84
+45 1.36 0.92
+60 1.38 0.89
+90 0.97
laboratory stock culture
2
filamentous green algae
probably Mougeotia collected in Anderson-Cue Lake.
NH-N mg/1
Figure VI-5 shows the results of phosphorus addition to natural
phytoplankton in Anderson-Cue water over a period of 120 hours. The
experiment was carried out to determine lag time in phosphorus uptake
by phytoplankton. It may be seen that maximum stimulation of algae by
phosphorus as detected by labeled C-14 carbonate fixation occurs in 72
hours.
This particular time dependent bioassay method is very useful as
a tool which can be used to follow the enrichment of single lakes by
observing the change in slope of the response line at successive time
periods. In addition comparative relationships among lakes within a
region can be made. As can be seen from Figure VI-5 the greatest de-
mand for phosphorus occurs during the summer in Anderson-Cue Lake and
decreases considerably during the fall when biological activity is
lower. Uptake of P in McCloud Lake is lower than Anderson-Cue and proba-
bly is due to a lower biomass of plankton organisms. Maximum uptake by
organisms in the control lake occurs in 48 hours.
Goldman (1965) has noted photosynthetic stimulation from the
addition of various compounds and elements in trace quantities. Lakes
showing micronutrient deficiencies frequently can be found and such
substances as vitamins and various cations doubtless play an important
role in algal growth cycles. Sources of these materials are provided
to lakes by (1) tributary streams, (2) runoff from land, or (3) inter-
change from sediments. Lakes near urban centers could very well re-
ceive some micronutrients from rain falling through polluted air.
-66-
-------
50
Anderson-Cue
. __ McCloud
x
I
40
30
20
10
Oct. '68
Oct. '68
24
48
72
Hogrs
96
120
Figure VI-5 Carbon - 14 Fixation by Phytoplankton Stimulated with
lOOjugm Phosphorus.
-67-
-------
Bioassay data on the two lakes show that cations limited algal
photosynthesis in trials carried out on McCloud Lake. No similar pattern
was observed in Anderson-Cue Lake during the same period. Two times
during the study vitamin additions stimulated algal growth in McCloud
Lake with no correlative response in Anderson-Cue water. It seems un-
likely that differences between the two lakes could be attributable to
variation in nutrient loading since enriched sewage effluent was not
added to Anderson-Cue Lake until March, 1967. Therefore, at the present
time differences in algal growth response to micronutrients appear to be
inherent between the two lakes.
Characteristics of Littoral Zone
Littoral plant growth as expressed in dry weight has remained
constant in both lakes. Since this area experienced an extended drought
during the winter and early spring months of the year 1967-1968, both
lakes dropped considerably, exposing former submerged stations. Those
stations out of water were not cut in December. A second problem en-
countered was that of migrant cows feeding in these areas. Adequate
fencing now prevents this from occurring. Table VI-7 contains the re-
sults of this part of the project. As might be expected plant growth
was greatest during the spring and summer months and least in the fall
and winter. Average dry weight per square meter of littoral growth in
Anderson-Cue Lake amounted to 50 grams which represented an increase
from 1967 of 20 grams/m^. Nutrients added to the lake expectedly would
enhance the growth of marginal vegetation, but it is too soon to say
that the 1968 data reflect the influence of induced eutrophication.
The yegetation of the two lakes was studied to determine the kinds
of plants, and the density and growth features of these plants in the
littoral zones. McCloud Lake was studied to find contrasts, if any, be-
tween it, without pollution, and Anderson-Cue Lake with well recorded
pollution.
As mentioned earlier, both of the lakes decreased in depth and
size in 1967-1968, and the receding waters left a wide zone where formerly
water flooded the shore. In both cases, the littoral was generally di-
vided into three zones as far as the kinds of plants and vegetation were
concerned. These were: (1) The Upper Zone with some shrubs present
or evidence that they were formerly present; (2) The Middle Zone where
grasses, sedges, and other herbs are abundant, but very few of the true
aquatic plants occur; and (3) The Lower Zone where distinctly hydrophy-
tic herbs and some aquatic plants occur. This Lower Zone has, due to
the receding water, a number of the plants usually common in open water,
such as the water lilies and the maidencane grass.
These three zones around McCloud Lake were more distinct and had
a denser population of plants than around Anderson-Cue Lake. Except for
the Lower Zone near the water the same species of abundant plants were
-68-
-------
Table VI-7
STANDING CROP ESTIMATES OF ANDERSON-CUE AND McClOUD LAKES
Plant
Station Dry \Vt. (g)
March May, J%7
Amlenon-Cuc
1 17.5749
3 12.2894
S 18.9235
6 44.36.53
7 5.2773
McCIoud
1 H.
-------
present in both littoral belts. The notable difference was an obvious
decrease in density and the number of kinds of plants present in the
Lower Zone along the waters edge of Anderson-Cue Lake, as compared to
McCloud Lake and to the density of plants in the Middle Zone of Anderson-
Cue Lake. This part of the Lower Zone that shows injury and death of
some of the Lower Zone plants is especially notable because some of the
plant species were not injured by what is presumed to be the toxic ef-
fects of the pollution and there are a few, such as Ludwegia alternifolj£'
which were only abundant in this "polluted zone".
The following is a brief and general list of the plants in each
of these three littoral zones, and also a list to show the plants of the
Lower Zone of Anderson-Cue Lake which died or became less abundant.
GENERAL PLANT COMPOSITION OF LITTORAL ZONES
McCloud and Anderson-Cue Lakes
Upper Zone
Hypericum fascilculatum
CephaIanthus occidentalis
Spartina bakerii
Andropogon spp.
Pluchea sp.
Eupatorium capillifolium
Juncus effusus
and other upland herbs
Middle Zone
Sabatia campanulata
Lachnocaulon minus
Pluchea foetida
Fuirena breviseta
Juncus sp.
Manisuris tuberculosa
Cyperus spp.
Xyris pallescens
Lachnocaulon sp.
Panicum hemitomon, and many other grasses and herbs
Most of these do not stand flooding
Lower Zone
Webateria (proliferating sedge, very small)
Sagittaria graminea
Fuirena spp.
Erioaulon compressum
Utricularia subulata
Utricularia cornuta
Cyperus spp.
-70-
-------
Lower Zone Cont.
Lachnocaulon minus
Sabatia campanulata
Lycopodium spp.
Xyris pallescens
Panicum hemitomon
Leersia sp.
Ludwegia alternifolia
Cephalanthus occidentalis (small)
CHANGES IN "POLLUTED PART" OF LOWER ZONE
Plants that seem definitely killed or reduced in size and number
Sagittaria graminea Lycopodium spp.
Lachnocaulon minus Fuirena spp.
Xyris pallescens and some of the Utricularia sp.
Sabatia campanulata
Plants that survived, and in some areas seem to grow better in the
"polluted part" of this Lower Zone.
Websteria sp. Panicum hemitomon
Leersia sp. Ludwegia alternifolia
Utricularia sp.
Of these, the Ludwegia seems to grow taller and denser.
This "polluted" part of the Lower Zone is widest, about 5-7 feet
along the southwest shore of Anderson-Cue Lake. It is narrower along
the northeast part of this lake, being about 2-4 feet wide. The dif-
ferences in width of the probably polluted zone may be due to more
prevailing winds that make higher water in the Southwest shore area.
This shore vegetation needs to be studied more intensely to find causes
and extent of this death of plants. Similar surveys of the kinds of
plants and vegetation zones should be made 3-4 times a year.
.Provisional Algal Assay Procedure (PAAP)
In the laboratory, preparation was made to adapt the provisional
algal assay procedure (PAAP), as proposed by the FWPCA's Joint Industry/
Government Task Force on Eutrophication. All three of the recommended
assay organisms are growing on a lighted shaker table at 24°C. Up to
this time, Selenastrum capricornutum has been used as the experimental
organism. The other two organisms, Microcystis aeruginosa and Anabaena
.flos-aquae. will be similarly tested.
-71-
-------
Five methods of assaying algal growth are being evaluated. These
include cell count, radiocarbon uptake, dry weight, light absorbance,
and adenosine triphosphate (ATP) level. Of thase methods, absorbance
and radiocarbon uptake are best suited for quantifying Selenastrum
growth. Dry weight and ATP determinations are not sensitive enough using
the inoculum size presecribed. Water samples from an unproductive and
a productive lake have been subjected to the PAAP. The results obtained
were as expected i.e., the test organism grew faster and reached higher
numbers in the productive lake water than in the unproductive lake water.
Further tests of this nature are now being conducted, using several dif-
ferent lakes as well as sewage treatment plant effluent.
Laboratory work on the PAAP study is being done routinely. To
date, all four of the methods of growth analysis outlined in the pro-
cedure have been tested with all three organisms. We have found only
two of these methods, cell counting and absorbance measurements, to be
reliable as tools for assaying growth because this study involves work-
ing with cultures of low cell number. However, another method, chlorophyll
a (Creitz and Richards, 1955), has been tried and found to be sensitive
enough to estimate growth at these low cell numbers. The possible use
of the Coulter Counter instead of the S-R cell to increase the precision
of cell counting is planned. Having established the assay methods, ex-
perimental work with lake water and lake sediment will be continued and
enhanced.
Preliminary tests using sediment collected from Anderson-Cue Lake
and inoculated with the organism Selenastrum demonstrated a significant
difference in the growth rates of the organisms in flasks containing
PAAP media plus sediment leached water versus PAAP media only. Increas-
ing the volume of sediment leached water added to each culture flask did
not increase the growth rate.
Extractive phosphate and alkaline phosphatase. Both parameters
were measured in the apical portions of the littoral vegetation as well
as attached filamentous chlorophyceae. Table VI-8 presents some pre-
liminary data. The data obtained thus far would indicate the growth to
be limited by the lack of available phosphorus.
Secondary and Tertiary Trophic Levels
The research bearing on the determination of secondary and
tertiary trophic levels in both lakes has involved work with zooplankton
and the planktivorous brook silverside (Labidesthes sicculus). This
fish is a significant element in the ecosystem of both Anderson-Cue and
McCloud Lakes feeding chiefly in pelagic areas on zooplankton and small
insects. It is very selective in what it eats, the size of the prey
being definitely correlated with fish size. Juvenile Labidesthes feed
-72-
-------
TABLE VI-8
EXTRACTIVE PHOSPHATE AND ALKALINE PHOSPHATASE
Extractive Phosphate Alkaline Phosphatase
Plant nig P/100 mg dry wt. Units/mg/hr
Mougeotia (outfall) 0.17 300.
Mougeotia (N.E. end) 0.01 60.
Ludwegia 0.10 16.
Websteria 0.03 16.
St. Johns Wort 0.04 3.
Utricularia 0.02 9.
Mayaca 0.01 7.
chiefly on rotifers and copepod nauplii while larger individuals eat
cladocera, adult copepods and occasional small insects. (Table VI-9
represents a partial spectrum of zooplankton ingested by Labidesthes
based on examination of gut contents). Labidesthes reproduce in spring
and early summer and few individuals live longer than a year, so the
food requirements of the population will change from summer to winter as
the fish grow. Thus the food availability is related not so much to the
total biomass of zooplankton as to the biomass of acceptable food items
during a given season. The delicate balance involved will be expected
to change as the lake becomes more eutrophic.
Zooplankton samples have been collected bi-weekly with a tow net
and microscopic counts have been made according to Standard Methods for
_the Examination of Water and Wastewater (1965). Individuals of each
important species were picked out under a dissecting microscope, dried
in a vacuum desiccator and weighed on a calibrated quartz helix (Table
VI-10). In order to get an adequate deflection of the helix, groups
of 5-200 individuals are weighed at a time and an average mass calculated,
Average mass per individual can be multiplied by number per square meter
of lake surface to obtain the biomass of the organism in gm/m2. Caloric
Values for species of zooplankters are determined using a microbomb
calorimeter. Thus several years of bi-weekly data on zooplankton popu-
lations can be readily converted into biomass or energy content.
Data for conversion of zooplankton numbers to biomass can be
found in Appendix F. Not all data are as yet available for conversion
of zooplankton numbers to biomass. The accompanying Tables VI-11 and
VI-12, showing the results from August 1967 and 1968, are examples of
the type of information which are available for each month of the inves-
tigation. Additional population densities (No./m2) for 1967 and 1968
are presented in Vol. II, Table 2-9, Appendix F.
-73-
-------
TABLE VI-9
FOOD OF IABIDESTHES SICCULUS
Labidesthes Standard length 19 mm Approximate dry weight 10 mg
Gut Contents Number Weight
Bosmina
Tropocyclops
Larval Cope pods
Chydorus
Labidesthes Standard
Gut Contents
Bosmina
Small Cyclops
Larval Cope pods
Chydorus
Diaptomus
Diptera
19
7
11
4
length 29 mm
22.5
3.5
1.6
4.8
Total weight
(dry) of food
32.4 yg
Approximate dry weight 23 mg
Number Weight (ug)
30
113
27
2
1
1
35.5
56.8
3.9
2.4
3.6
45.0
Total weight
(dry) of food
147 U8
Labidesthes Standard length 37 mm Approximate dry weight 49 mg
Gut Contents Number Weight (ug)
Bosmina
Small Cyclops
Larval Cope pods
Diaptomus
Daphnia
Diaphanosoma
14
30
3
14
8
1
16.5
15.1
0.4
50.4
31.4
1.4
Total weight
(dry) of food.
115 yg
-------
TABLE VI-10
DETERMINATION OF ZOOPLANKTON WEIGHTS IN
ANDERSON-CUE AND McCLOUD LAKES
Range Avg. Dry
No. of Total Dry Weight Weight
Organism De
Keratella
Larval Copepods
Tropocyclops
Bosmina
Diaphanosoma
Diaptomus
Daphnia
Holopediura
Mesocyclops
Chaoborus
'terminations
4
2
5
5
6
10
7
2
10
5
Individuals
320
200
125
97
110
100
70
18
95
35
(micrograms)
0.036-0,053
0.145-0.148
0.371-0.608
0.73-1.38
0.872-1.82
3.11-4.53
1.49-5.77
4.5-6.6
4.81-10.8
14.7-84.6
(micrograms;
0.0435
0.146
0.503
1.182
1.423
3.603
3.922
5.549
8.47
45.6
Weights in this table were obtained by weighing groups of from 5-200
individuals of each species on a calibrated quartz helix.
-75-
-------
TABLE VI-11
ZOOPLANKTON DENSITIES AND CALCULATED BIOMASS
FOR AUGUST 1967
Anderson-Cue Lake
3 Aug.
11 Aug.
26 Aug.
Tropocyclops
Mesocyclops
Diaptomus
Larval Copepods
Bosmlna
Daphnia
Diaphanosoma
Holopedium
Keratella
No/m2
4,715
3,169
11,038
18,987
1,227
3,156
879
0
9,922
mg/m2
2.372
26.841
39.770
2.772
1.450
12.378
1.251
0.0
0.432
No/m2
2,160
1,452
5,179
27,836
5,706
3,876
0
0
9,065
mfc/m2
1.086
12.298
18.660
4.064
6.744
15.202
0.0
0.0
0.394
No/m2
19,742
13,271
22,484
74,147
18,050
761
0
0
26,699
mR/m2 __
9.930
112.405
81.010
10.825
21.335
2.984
0.0
0.0
1.161
Total
87.266 58.448
Avg. Blomass (mg/m2) 128.45
239.650
McCloud Lake
Cyclops (sp. 1)
Cyclops (sp. 2)
Diaptomus
Larval Copepods
Bosmina
Daphnia
Diaph'anosoma
Holopedium
Keratella
Total
5,625
3,781
9,628
36,030
6,503
105
367
0
41,370
2.829
32.025
34.690
5.260
7.688
0.412
0.522
0.0
1.800
5,371
3,611
8,713
47,800
10,540
79
26
0
66,190
2.702
30.585
31.393
6.979
12.458
0.310
0.037
0.0
2.879
85.226
Avg. Biomass (mg/m2) 86.28
87.343
-76-
-------
TABLE VI-12
ZOOPLANKTON DENSITIES AND CALCULATED BIOMASS
FOR AUGUST 1968
Anderson-Cue Lake
12 Aug
19 Aug.
26 Aug.
Cyclops (sp. 1)
Cyclops (sp. 2)
Diaptomus
Larval Copepods
Bosmina
Daphnia
Diaphanosoma
Holopedium
Keratella
Total
No/m2
24,200
7,991
144,514
192,000
1,142
228
0
0
58,901
mg/m2
12.173
67.684
520.684
28.032
M.350
0.894
0.0
0.0
2.562
''633.379
No/m2
34,496
16,666
92,690
90,635
685
228
228
0
42,464
mg/m2
17.351
141,161
333.962
13.233
0.810
0.894
0.324
0.0
1.847
509.583
No/m2
43,847
44,385
291,058
194,756
7,801
807
4,035
0
538
mg/m2
22.055
375.941
1048.682
28.434
9.221
3.165
5.742
0.0
0.023
1493.263
Avg. Biomass 878.74 mg/m2
McCloud Lake
Cyclops (sp. 1)
Cyclops (sp. 2)
Diaptomus
Larval Copepods
Bosmina
Daphnia
Diaphanosoma
Holopedium
Keratella
Total
36,528
11,187
25,570
86,982
27,168
1,142
12,785
228
2,511
18.374
94.754
92.129
12.699
32.113
4.479
18.193
1.265
0.109
23,743
19,405
34,702
101,137
24,656
0
20,775
0
1,826
11.943
164.360
125.031
14.766
29.143
0.0
29.563
0.0
0.079
27,976
28,514
91,998
80,162
112,980
0
35,625
0
0
14.072
241.514
331.469
11.704
135.542
0.0
50.694
0.0
0.0
274.135
Avg. Biomass 478.00 mg/m2
374.885
784.995
-77-
-------
Populations of many zooplankton species have shown tremendous
fluctuations over the time period of the study. Some of these fluctua-
tions are seasonal in nature or weather-induced but others may be
correlated with changing physio-chemical parameters of the lake. De-
finite trends caused by increased enrichment have not yet been established.
The change in L. sicculus population in Anderson-Cue Lake has been
very spectacular. The population has dropped from an estimated 130,000
in November, 1967, to virtually zero at present. The McCloud population
has shown no corresponding decline.
Ij. sicculus has previously been shown to be very susceptible to
high turbidities often accompanying pollution, but Anderson-Cue turbi-
dities have not risen nearly as high as those in some local lakes where
L;. sicculus is abundant. Possibly the decline was caused by the ex-
tremely low water level and concomitant lack of littoral vegetation
suitable for spawning.
Table VI-13 contains a partial faunal list from the study lakes.
This information was provided by Paul and Karolyn Maslin whose research
dealing with secondary and tertiary production levels formed the basis
for two dissertations reproduced in Vol. II as Appendix A and B. In-
vestigations of this kind are very important as virtually no information
is available for the southeast U.S. regarding zooplankton species di-
versity, production rates and changes in species composition as influ-
enced by the eutrophication process. The most significant conclusions
drawn from these works are described below.
Equilibrium between zooplankton and environment. Slobodkin (1954)
demonstrated that a fairly long time period, on the order of 40 days, is
required for a single cladoceran species, Daphnia obtusa, to reach an
equilibrium population is a constant laboratory environment and has sug-
gested that natural populations may never reach equilibrium before
further environmental changes occur. In the light of the present study
several additions may be made to Slobodkin's hypothesis. First, in a
mixed culture or natural community the environment of any one species
includes all of the other species as well as the physical parameters.
If some environmental change occurs, all populations will tend to ad-
just to the new conditions. The adjustment is not instantaneous but
requires a time period of at least one and probably several generations.
As any one species population changes in adjustment to the environment
it will automatically alter the environments of all other species. Thus
the time required for a community to equilibrate is greatly extended.
If other changes should occur before equilibrium is reached, the commun-
ity will be in perpetual nonequilibrium. Forces will always be present
pushing the populations toward equilibrium, but equilibrium can never
be attained, since the equilibrial size of any population will be con-
stantly changing.
-78,
-------
TABLE VI-13
A PARTIAL FAUNAL LIST FROM LAKES ANDERSON-CUE AND McCLOUD
FISHES:
Chaenobryttus gulosus
Etheostoma fusiforme
Fundulus chrysotus*
Fundulus lineolatus*
Gambusia affinis
LIMNETIC CLADOCTERA:
Bosmina coregoni
Daphnia arabigua
LITTORAL CLADOCERA:
Heterandria formosa
Labidesthes sicculus
Lepomls macrochirus
Micropterus salmoldes
Diaphanosoma brachyurum
Holopedium amazonicum
Eurycercus lamellatus*
Graptoleberis testudinata
Ilyocryptus splnifer
Macrothrix rosea
Monospilus dispar
Pleuroxus sp. (Hastatus?)
Simocephalus expinosus*
Acroperus harpae
Acantholeberis curvirostris
Alona affinis
A. costata
A. guttata
A. quadrangularis
Alonalla globulosa
Anchistropus minor*
Camptocercus rectirostris
Ceriodaphnia pulchella
Chydorus biocornutus*
C. piger
C. sphaericus
*indicates species found only in Lake McCloud
LIMNETIC COPEPODS: LITTORAL COPEPODS:
Diaptomus floridanus
Cyclops bicuspidatus
Tropolyclops prasinus
LIMNETIC ROTIFERS:
Conochiloides sp.
Conochilus sp.
Keratella americana
K. taurocephala
Pedalia sp.
Polyarthra sp.
Cyclops exilis
Eucyclops speratus
LITTORAL ROTIFERS:
Brachionus sp.
Keratella serrulate
Lecane spp.
Macrochaetus sp.
Monommata sp.
Monostyla sp.
Trichocerca spp.
-79-
-------
Demonstration of cause-effect relationships between environmental
variables and population size or group biomass is difficult because of
the nonequilibrial nature of the relationship, as well as the lag re-
sponse described by Slobodkin (1954) and Edmondson (1965). The lag
period necessary for any species population to adjust to an environmental
change is dependent upon temperature and food (Ingle, e_t al, 1937;
Hazelwood and Parker, 1961; Elbourne, 1966). Accordingly, no two species
can be expected to have the same lag time, and lag time for any one
species will not be constant. Even if variations in a single environmen-
tal factor are responsible for changes in zooplankton biomass, correla-
tion of biomass with the particular factor may be poor. Comparison of
taxonomic groups, or even separate species, with environmental factors
should give truer correlations but even these will be blurred by vari-
ations in time lag with environmental changes.
Competition patterns of zooplankton species. The correlation
coefficients between populations of the different cladocera showed no
tendency for any species to decline while any other species was increas-
ing. On the contrary, some showed positive correlations (D. ambigua to
H. amazonicum; JB. coregoni to D. brachyurum). The pattern of dominance
in cladocera, however, showed that a given set of environmental condi-
tions might be distinctly more favorable to one species than to another.
Even though two species were positively correlated, dominance of one over
the other at a given time was almost certain. In the summer of 1968 in
Anderson-Cue, all cladocera disappeared from the lake for a short time.
As they began to come back, three species were seen. J3. cor eg on ia and
£. ambigua appeared together, with both populations increasing rapidly
but Bosmina. increased more rapidly than Daphnia, exceeding it in numbers
by an order of magnitude as both populations began to level off. D.
brachyurum appeared about two weeks later than the other two but multi-
plied at a rate nearly equivalent to Bosmina's initial rate and soon
achieved a population roughly equal to Bosmina. The Bosmina population
then decreased by about an order of magnitude while Diaphanosoma de-
creased only slightly, thus acquiring dominance.
The above example shows two things. First, competition probably
exists between these species. Second, the effects of competition can
be obscured by changes in the environment. When cladocera started to
come back into the system all three were favored, just as populations
of two or more species inoculated into a new medium would increase ini-
tially before competition became important. After the populations
reached a "normal" level a distinct tendency for one to dominate was
displayed.
-80.
-------
Food-predator-climate relationships. The presence of competition
but not competitive exclusion is explained by the non-equilibrium nature
of the ecosystem. If an equilibrium is reached, the outcompeted species
will be eliminated, but environmental changes effectively give the losing
species a new start. If the environment is sufficiently transitory
species which would compete strongly in a laboratory culture may show a
distinctly positive correlation. In the event that biological equili-
brium should be reached, causing exclusion of some species nearly all
fresh-water plankters have some sort of resting stage which allows them
to develop a new population at a later time (Hutchinson, 1967).
The smaller coefficients of variation for groups as compared to
species and the better interlake correlation of total and group biomass
as compared to species biomass indicate that factors acting to control
the populations are acting on the whole trophic level rather than on
individual species. The good correlation (r = 0.686) between zooplankton
biomass in the two lakes indicates that climatic factors (i.e., factors
which would affect both lakes) play a large part in regulating'zooplank-
ton populations, but the mechanism for action of climate on zooplankton
is not intuitively obvious.
While the summer decline was statistically significant in both
lakes, the reason it occurred is less easily demonstrated. When the
summer data were ignored the zooplankton biomass followed the tempera-
ture curve. A possible explanation for the summer drop would be that
temperature had passed the optimum for species present. However, zoo-
plankton biomass returned to normal and, indeed, to its highest value
while temperature was still above the level of the initial drop. Also
the recovery from the summer low began while temperature was at maxi-
mum. The summer low could not be due to lack of food because both
primary productivity and chlorophyll concentration of phytoplankton
were higher during the summer.
A study of the reactions of individual species to the summer
discontinuity provides an insight into its cause. Only the larger
zooplankters showed a significant decline during the summer. Inter-
mediate species showed essentially no response, while very small species
such as the rotifers increased significantly. Also, rarer species of
rotifers were much more likely to be seen during the summer biomass low.
A further clue is provided by the fact that larval copepods did not
decline; they even increased slightly. Evidently conditions were favor-
able for copepod reproduction since fewer adults were able to produce
as many or more young. Accordingly the decline in adults must have been
due to an increased death rate. This in turn points to an increased
predation rate in summer with apparent selection for the larger forms
producing results similar to those described by Brooks and Dodson (1965).
An explanation for increased predation during summer is readily
available: Labidesthes sicculus and Lepomis macrochirus are spawning
and the young of both are much more dependent upon zooplankton than are
the adults. Hubbs (1921) and Werner (1969) have discussed the migration
-81.
-------
of fry of these species into the limnetic zone where they feed upon
zooplankton, particularly microcrustacea. McLane (1955) reported that
in Florida Ij. sicculus spawns throughout the summer while _L. macrochirus
spawns from May to October with most intensive spawning in June. Since
the bluegill fry spend ca. 1.5 months in the limnetic zone (Werner, 1969),
their period of heaviest predation falls exactly during the summer zoo-
plankton low. The briefer summer decline in Anderson-Cue, 1968, as
opposed to 1967 or McCloud, 1968, also supports the predation mechanism;
the JL. sicculus population in Anderson-Cue, 1968, for some unknown reason,
was very much reduced by compari with the 1967 population or the
McCloud population.
When the period of summer decline is ignored, total zooplankton
biomass is closely correlated with both temperature and primary produc-
tivity. Since temperature and primary productivity are strongly corre-
lated throughout the year, it seems reasonable that the influence of
climate on zooplankton biomass, as evidenced by the close correlation
between lakes, is due to two principal factors, neither of which acts
directly on the zooplankton. (1) Temperature limits primary production
(given a reasonably constant nutrient supply), thus limiting the food
available to zooplankton and, accordingly, the zooplankton during most
of the year. (2) The onset of fish reproduction, with its concomitant
predation surge, is determined by climatic factors, such as temperature
and photoperiod, and thus is synchronized in both lakes.
In these lakes zooplankton as a group is food-limited during
most of the year. During that period competition for food should be
important. In the summer, however, when zooplankton biomass is at its
lowest and primary productivity is at its highest, no competition for
food should exist. Thus the summer is the period when the rotifers,
relatively predation immune due to their small size, develop their
largest populations. Also several rarer species of rotifers are much
more common during the summer. Their apparent relationship to tempera-
ture merely reflects their reaction to the decreased competition during
the summer. The same general explanation pertains to the change in
frequency of Daphnia and Bosmina dominance with warm temperatures. Tem-
perature is not directly involved; Daphnia, being larger, receives
greater predation pressure than Bosmina.
Secondary production estimates. The estimations of secondary
production and efficiency are, admittedly, very rough. The range from
minimum to maximum estimate covers about an order of magnitude. How-
ever, the ranges for the 1968 values are reduced from that for 1967,
probably reflecting the greater accuracy obtained with more frequent
sampling. The range of efficiencies determined includes from a rea-
sonably low efficiency to one impossibly high. The efficiencies asso-
ciated with the "best estimate" are in line with the general ecology
efficiency of 8-12 percent (Slobodkin, 1968).
-82-
-------
An advantage of this method of estimating zooplankton production
is that contributions made by each species or higher taxonomic group can
be assessed. Thus in both Anderson-Cue and McCloud, 1968, copepods
accounted for ca. 75 percent of the production, cladocera contributed
ca. 24 percent, and rotifer species present coupled with their sporadic
occurrence accounted for their low contribution to production.
There have been a few previous determinations of aquatic secondary
production. As pointed out in the introduction, most of these were only
rough estimates. The most important studies are summarized in Table VI-14.
For comparative purposes all values are listed as originally reported
and then as converted to kcal m~2 year-1. Of the previous workers only
McAllister reported any boundaries to production. The range of values
from the present study is quite similar to that reported by McAllister
and includes all of the other values for standing fresh waters. The
"best estimate" of mean annual zooplankton production in Lakes Anderson-
Cue and McCloud is ca. 50 kcal m-2. As one would expect for oligotrophic
lakes, this value lies toward the low side of the range for standing
waters.
Zooplankton abundance factors. Of the environmental parameters
examined, fluctuations in primary productivity and temperature had the
greatest effect on littoral zooplankton abundance. This pattern was
especially seen in cladocera and rotifera where primary productivity
and temperature would be correlated with the rate of reproduction, and
thus, changes in population densities of both groups.
In the multiple regression analyses copepoda were not highly
correlated with the three environmental parameters. According to
Hutchinson (1967), variations in copepod egg number are less clearly
associated with environmental conditions than in cladocera. Also, the
immature stages of the life cycle presumably give copepods a greater
range of filtrable food, thus making them more adjustable to varying
conditions than cladocera.
Both Anderson-Cue and McCloud had their highest density of
cladocera in the summer, 1968, corresponding to high primary produc-
tivity. While both showed a decreased density in the fall, Anderson-
Cue had a high density of cladocera from December through February and
McCloud maintained low populations. This accompanied a high primary
productivity.
Primary productivity in the two lakes was significantly correlated
(r - 0.511, p - 0.01) in 1968-1969. However, in 1969-1970, this corre-
lation was higher (r» 0.907, p = 0.001), indicating a greater similarity
between the lakes.
.83-
-------
I
00
P"
I
TABLE VI-14
SOME REPRESENTATIVE RATES OF SECONDARY PRODUCTION IN AQUATIC ECOSYSTEMS
Investigator
Odum and Yount
(1954)
Stress, et al
(1961)
Straskraba
(1963)
Ilkowska, et al
(1966)
McAllister
(1969)
Present study
Organisms
crustacean
zooplankton
littoral
zooplankton
limnetic
zooplankton
marine
zooplankton
limnetic
zooplankton
Ecosystem
Reported Rate
9 1
most Silver Springs, 240 g m zyear
herbivores Florida
bog lake
fishpond
fertile area
Pacific
oligotrophic
lakes
8 g m 2year~
1.7 g N m~2year""1
1.5-23.2 g C m"2year-l
4-52 g m~2year~1
Converted to
kcal m"
1200
40
53
two eutrophic 27 and 40 g nT^ear""1 135 and 200
lakes
15-232
20-260
-------
In 1969-1970 both lakes again had high simmer cladoceran populations
and decreasing fall populations. Differences between cladoceran densi-
ties were probably due to an interaction between environmental parameters.
Decreasing primary productivity and temperature and habitat changes due
to increasing lake level resulted in a decrease in population density in
both lakes in the fall. However, the greater abundance of C. sphaericus
in McCloud than in Anderson-Cue from January through March,~~1970, sug-
gests that the better developed littoral zone of McCloud was not as
strongly affected by lake level fluctuations. Benthic and vegetative
inhabiting species had decreased population densities in both lakes.
Lake level. Fluctuations in lake level and the resultant effects
on vegetation in the littoral zone had the greatest influence on species
diversity. The general physical condition of sand lakes produces drastic
changes in lake levels. During this study the above characteristic was
observed. It may be expected that the variations found in the littoral
zone, as affected by drought, would influence the species diversity.
Since sampling depth was kept constant throughout the study, vegetation
in the sampling area was reduced in the fall due to the rapid increase
in lake level, slow macrophyte growth and delayed aufwuchs colonization.
The continued increase in lake level might also have been responsible for
the lower values of primary productivity in both lakes in the spring
of 1970 compared to the spring of 1969. The pattern of species diversity
was best related to the changes in lake level, since diversity was low
as lake level increased and was high when lake level stabilized or was
dropping. This would affect most chydoridae species since they are
normal inhibitors of littoral vegetation. Exceptions may be found in
those species either inhabiting the sediment water interface or the
limnetic zone (A. quadrangularis and C. sphaericus).
Prey selection. Littoral cladocera were the most important food
items for Etheostoma fus iforme and Heterandria formosa. When littoral
cladocera were scarce E. fusiforme fed mainly on copepoda and nonplank-
ton, while H. formoaa chiefly ate rotifers. Food selection was deter-
mined by size and accessibility of prey. Cladocera were the most important
items in the diet of both fishes. Energetically, this seems reasonable,
since littoral cladocera are poor swimmers compared to copepods and
would be easier to capture. Because of their small size, rotifers would
be energetically important food sources only when numberous.
When cladocera were scarce, E_. f us if orme consumed copepods and
nonplankton, while H. formosa ate mainly rotifers and some nonplankton.
Rotifers were a large component of the diet even when they were not
abundant.
-85-
-------
In Anderson-Cue E. fuslforme had a mean electivity index of -0.43
for copepods, while H. formosa had a value of -0.49. In McCloud the
mean electivity index of 12. fusiforme was +0.12 and that for H. formosa
was -0.28. This implies that E. fusiforme was somewhat better at ob-
taining copepods than H. frarmpsa, but they were not highly selected by
either fish. Also IS. fusiforme in McCloud was dependent on copepods
for a longer time than in Anderson-Cue, due to the lower cladoceran
populations.
As evident from the low levels of predation pressure (Table VI-15))
the two fishes had an abundant food supply when cladocera were numerous.
Because of partitioning of resources when cladocera were scarce, compe-
tition did not occur. The period when their feeding habits were most
similar (when their niches overlapped) was when food supply was not
limiting.
Prey selection appeared to be determined by a combination of
factors. Both fishes had high mean electivity indices for the same
species of cladocera. These were generally large and/or benthic species.
£ fusiforme always had higher indices for the smaller vegetative in-
habiting species, but these were usually negative. Mean indices for £.
sphaericus were similar, indicating an equal availability.
If the average percent of the diet made up by each cladoceran
species is examined, the results are similar. The large benthic species
averaged 5.0 percent of the diet of E. fusiforme and 2.4 percent of the
diet of H. formosa. Small species which inhabit the vegetation consti-
tuted 0.9 percent of the diet of IS. fusiforme and 1.6 percent of the diet
of H. formosa. Thus, the large benthic species were more important to
both fishes than the small vegetative inhabiting species.
Size and accessibility seemed to be equally important factors in
food selection. Accessibility refers to the behavior of the prey, such
as concealment or ease of escape. It also refers to characteristics
of the predator which equip it for catching certain prey. This is simi-
lar to the definition of Ivlev (1961), although he considers accessibil^^
to be more a property of the prey. To a slight extent, size is a com-
ponent of accessibility, since larger plankters are usually better
swimmers. Also, an organism may be too large or too small to be eaten.
In this case all organisms studied were within a suitable size range
for both fishes.
Large benthic cladocera were selected by both fishes over small
species. However, since IS. fusiforme rests on the bottom these cladocef*
may be more accessible, which would explain higher electivity indices.
Among the rotifera and copepoda, accessibility seemed to be more impor-
tant than size. H. formosa selected rotifera over copepoda, perhaps be"
cause it was not as efficient as IS. fusiforme at catching copepods.
-86.
-------
TABLE VI-15
Monthly Predation Pressure by E_. fusiforme and H. fonnosa in Lakes
Anderson-Cue (A-Q) and McCloud (McC) , 1969-1970.
Organism Jul Aug Sep Oct Nov
A. curvirostris
A. harpae
A. qcadrangularis
C. piger
C. sphaericus
G. testudinaria
I. apinifer
H. rosea
P. striatus
S. exspinosus
Lecane spp.
Monostyla sp.
Copepoda
A-Q
McC
A-Q
McC
A-Q
McC
A-Q
McC
A-Q
McC
A-Q
McC
A-Q
McC
A-Q
McC
A-Q
McC
A-Q
McC
A-Q
McC
A-Q
McC
A-Q
McC
0.05
0.008
0.20
0.08
0.08
+
0.09
0.12
0.006
4-
0.34
0.03
0.021
0.52
0.08
0.63
0.04
0.05
0.05
0.03
0.35
0.04
0.02
+
4-
0.89
0.05
4-
0.64
++
0.02
0.03
0.93
0.17
0.31
0.21
0.054
0.14
0.05
0.16
0.10
0.08
0.038
0.01
0.24
0.09
H-
0.10
H-
0.22
4-
0.07
0.10
0.08
0.09
0.04
0.003
4-
4-
0.058
0.12
0.002
0.19
0.10
0.008
0.25
4-
0.008
0.28
+
0.17
0.17
0.41
0.23
0.03
0.024
+
0.01
0.01
4-
0.49
0.43
0.012
4-
4+
0.027
4-
4-
0.01
0.033
0.016
Dec
4-
0.11
4-
0.04
0.05
+
4-
0.36
0.37
0.072
0.01
4-
0.24
4-
4-'
0.105
0.12
0.007
0.16
0.006
0.03
Jan
0.24
0.68
0.59
4-
0.52
0.09
0.10
0.82
0.20
0.03
4-
0.044
4-
4-
4-
0.02
0.24
0.05
0.06
0.03
0.04
Feb
4-
0.
0.
0.
0.
0.
3.
0.
4-
0.
0.
0.
4-
0.
0.
0.
0.
025
62
49
087
045
56
05
024
02
014
014
006
01
018
Mar
4-
0.17
4-
0.107
4-
0.25
0.13
0.36
4-
+
+
4-
0.016
0.02
0.007
0.032
4- - eaten, but not present in plankton sample.
4-f - large quantity eaten, but not present in plankton sample.
.87-
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Abundance, of course, plays some role. If an organism is so
rare that it is seldom encountered, it would not seem to be energetically
important. However, small cladocera constituted sizeable portions of the
diet when scarce. Thus, abundance was not a significant factor in prey
selection.
Predation pressure. The feeding of jS. fusiforme and H. formosa
on the littoral zooplankton is only a small part of the total predation.
All of the littoral fishes feed to some extent on them. Also, species
of game fish and pelagic fishes spend a portion of their lives in the
littoral. Bluegill fry, in particular, feed heavily on littoral cladocera
in these lakes (personal observations).
The values of predation pressure were usually low. The highest
value was on £. sphaericus, 3.56 percent, in February, 1970. Dodson
(1970) measured removal rates of Daphnia due to salamander and midge
larvae predation in a similar fashion. When his values are expressed
as percent removal per day, they are of the same order of magnitude as
the values for £. sphaericus in this study. Hall (1964) estimated total
predation pressure on Daphnia in the summer to be 21.9 percent per day.
He concluded that predation was the most important factor controlling
population size in the summer.
The fact that gut clearance rate increases with temperature and
that fish densities are greatest in the summer indicates a greater pre-
dation in the summer, which corresponds to the time of highest number
of species and abundance of littoral zooplankton. This strengthens the
observation that the littoral zooplankton are not controlled by El.
fusiforme and H. formosa. However, bluegill fry enter the littoral in
late August from the limnetic zone. Since this is a time of decreasing
zooplankton populations, they may exert a much stronger predation
pressure.
The effect of predation on prey populations has been examined.
Slobodkin (1961) speculated that where 'two species are limited by pre-
dation, they can coexist if they differ from each other ecologically to
some significant degree. The stability of a system is increased by
ecological diversification of the species. Connell (1961) found that
predation tended to decrease competition between two species of barna-
cles. Paine (1966) suggested that animal species diversity is related
to the number of predators in a system and their efficiency in pre-
venting single species from monopolizing some limiting resource.
Since many species of littoral zooplankton are approximately
the same size and utilize the same food supply, they would compete when
these resources were limiting. By keeping prey species populations be-
low the level of resource limitation, predation could play an important
role in maintaining a high species diversity.
.88.
-------
Eutrophication effects^ It was difficult to demonstrate a cause-
effect relationship between changes in littoral zooplankton and enrichment
of Lake Anderson-Cue. Brooks (1969) mentioned that an increase in stand-
ing crop of herbivores was an expected consequence of enrichment. The
total zooplankton was generally greater in Anderson-Cue than in McCloud.
However, a decrease in abundance was seen in both lakes the second sampl-
ing year. Changes in abundance, species composition and diversity were
more likely correlated with changes in the littoral zone as a result of
lake level fluctuations than with enrichment.
Whiteside and Harmsworth (1967) found a high correlation between
transparency and species diversity in Danish and Indiana lakes. Since
chydorids are typically inhabitants of the macrophytic vegetation, they
suggest that this habitat extends to greater depths in clearer lakes.
Lesser penetration of light in more enriched lakes due to phytoplankton
blooms and dissolved organic matter would decrease habitat diversity and
thus, species diversity. Whiteside (1970) divided the chydorid associa-
tions into three areas: the littoral vegetational, the littoral benthonic
and the limnetic. He found that in lakes of extreme eutrophy, limnetic
species (C_. sphaericus, A. rectangula) comprised most of the chydorids.
The benthic species were not as much affected by eutrophication as those
which inhabited the littoral vegetation.
Changes in habitat diversity can occur as a result of long-term
phenomena, such as eutrophication, or short-term phenomena, such as lake
level fluctuations. Both would have similar effects on diversity and
density of littoral zooplankton. Also, changes in the composition of
zooplankton may result from selective predation. In order to use lit-
toral zooplankters as indicators of eutrophication, the effects of
changes in environmental parameters, as well as selective predation, on
the population dynamics of littoral zooplankters must be understood.
The effects of environmental variables on littoral zooplankton
populations are complex. Because of their effect on the rate of repro-
duction, primary productivity and temperature are probably the most
important controlling factors. However, the correlations between popu-
lation and density and primary productivity could be improved if the
contribution of periphyton was considered. According to Fryer (1968),
periphyton is an important food source for several species of Chydoridae.
This and earlier studies have shown that changes in habitat
diversity affect population density, as well as diversity of littoral
zooplankton. Although lake level fluctuations were monitored, this did
not give an adequate reflection of changes in the littoral zone. To
determine the effects of eutrophication on littoral zooplankton, quanti-
tative measurements of changes in macrophytes and aufwuchs are needed,
since these would be more indicative of changes in habitat diversity.
-------
Predation by _E. fus 1 forme and H. formosa does not appear to control
population densities of littoral zooplankters in these lakes. However,
a measure of total predation might show this to be an important factor,
especially when game fish fry are present in the littoral zone.
-90-
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SECTION VII
TROPHIC STATE STUDIES OF lAKES IN NORTH CENTRAL FLORIDA
A survey of the physical, chemical and biological features of
lakes in north central Florida was initiated in 1968. This was under-
taken for several specific objectives: (1) to assess the present
trophic quality of lakes in this region; (2) to provide baseline data for
future studies on rates of changes in the quality of these lakes; (3) to
gather sufficient information to evaluate the appropriateness of present
trophic state criteria in sub-tropical lakes; and (4) to provide neces-
sary data to construct an equation or index (or indices) for trophic
states in sub-tropical lakes.
Sampling programs have been initiated on lakes in three regions
of north central Florida: (1) Alachua County (the location of Gaines-
ville); (2) the Central Highlands in Putnam and Clay Counties; and (3) the
lower Oklawaha River basin in Lake, Seminole, and Marion Counties. The
most extensive sampling program is being conducted on the lakes in Alachua
County (for reasons of convenience and also because of the wide range of
lake types available within the county). Because of the larger number of
lakes in the Central Highlands region, only selected lakes are included
in this survey. The two model lakes described in earlier sections of
the report are located within this region. The lakes in this area are
somewhat different from and generally higher in quality than lakes in
Alachua County. These lakes are becoming increasingly important recre-
ationally as locations of homes for vacationers and retirees. Conse-
quently it was considered important to study the trophic nature of these
lakes. The lower Oklawaha River basin contains some of the largest and
most enriched lakes in Florida. These lakes are important for recrea-
tion, and in the past were considered among the best bass fishing lakes
in the state. Considerable evidence of rapid eutrophication has been
found in some of the lakes within recent years, and agricultural runoff
has been implicated as a major contributor of nutrients. In view of
these facts it was felt that any study of eutrophication would be in-
complete without some information on these lakes. Numerous studies have
already been made on the Oklawaha lakes, and studies by groups such as
the Florida Game and Fresh Water Fish Commission are continuing. It is
not intended that the present study duplicate these efforts but comple-
ment them. Because biological information needed in trophic state indices
is not available for the lakes, limited sampling on six of the largest
lakes in this region has been undertaken.
Both qualitative and quantitative studies of the trophic state of
lakes in north central Florida were performed. The results of the quali-
tative study, using present trophic state criteria, illustrated the need
-91-
-------
for a new, more quantitative approach to trophic state classifications.
In this section both the qualitative and the quantitative trophic state
studies are discussed. The quantitative study resulted in the formula-
tion of the Trophic State Index, a novel classification criteria utili-
zing multivariate techniques.
Qualitative Trophic State Study
This section describes initial attempts to classify the lakes
using present trophic state criteria. It is divided into two parts.
Part one describes the trophic state of the Alachua County lakes while
the second describes the trophic state of the lakes in the Oklawaha
River Basin.
Alachua County lakes. All the significant lakes in the county
are included in the survey; criteria for significance include size (all
lakes larger than about 3 hectares were sampled) and economic or recre-
ational value (any lake with a public or private access road or a per-
manent dwelling on its shore was considered significant in this regard).
Thirty-three lakes in or partly in Alachua County were found to meet
these criteria. The locations were determined from U.S.G.S. topographic
and county road maps. The lakes and their locations are listed in
Table VII-1 and shown in Figure VII-1. Not all the lakes are named,
and some of the names are known only to local residents. In some cases
conflicting names appear on different maps; we have assumed the most
recent map to be correct in these instances. Several other lakes appar-
ently meeting the criteria are indicated on topographic maps but were
either swamps or completely dried land at the time of sampling.
Previous limnological efforts in Alachua County have been rather
sparse. Because of its unusual characteristics, Lake Mize has been the
subject of several studies, including Harkness and Pierce (1940) and
Nordlie (1967). Odum (1953) reported some values for dissolved phos-
phorus in Lake Mize and several other lakes in the county. Nordlie
(1967) studied primary production and its limiting factors in Bivens
Arm, Lake Mize and Newnan's Lake. The nitrogen cycle, nitrogen fixation
and organic color in Lake Mize have been studied by Brezonik (1969).
Miscellaneous data on several of the larger lakes can be found in Florid*
Geological Survey publications (e.g. Clark e_t a_l, 1962, 1964).
It is apparent from Figure VII-1 that the lakes are not uniformly
distributed throughout the county. Most of the lakes are located in the
eastern half of the county, and the four major lakes are in the eastern
third. The terrain surrounding the lakes is remarkably varied, consider
ing the small geographical area. Most of the lakes in the eastern part
of the county have heavily forested shorelines, but the type of forest
varies for different lakes. The large lakes have an outlet and one or
more inlet streams, but many of the small lakes have neither.
-92-
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Table YTI-I
LAKES IN ALACHUA COUNTY
Number Name
Location
Depth1
1 Depth in meters
"Area in hectares
1 Symbols are as follows:
O oligotrophic
M = mesotrophic
E = eutrophic
HE «- hypereutrophic
D * dystrophic
S «= senescent
C >> high organic color in lake water
Area*
Type'
Santa Fc Basin
1
2
3
4
5
Orange
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Santa Fe
Little Santa Fe
Hickory Pond
Altho
Cooter Pond
Creek Basin
Elizabeth
Clearwatcr
Hawthorn
Little Orange
Unnamed
Moss Lee
Jeggord
Still Pond
Lochloosa
Orange
Palatka
Newnan's
Mize
trout
North of Melrose
North of lake (1)
West of lake (2)
East of Waldo
Norlh central part of county
Southwest of Melrose
Southeast of Melrose
Hawthorn
Southeast of Hawthorn
South of lake (9)
Southeast of lake (10)
South of Hawthorn
East of Lochloosa
Southeast part of county
Southeast part of county
South of lake (17)
East of Gainesville
Northeast of Gainesville
Southeast of Gainesville
8.5
6.5
4
4.5
3
2.5
3
3.5
3
4
4
3
3
1
2
22
1.5
1760
464
32
228
124
57
35
241
50
57
85
2484
3105
25
2562
0.9
15
OC
OC
OC
OC
M
MC
O
EC
MC
MC
D-MC
E
E
D-S
HEC
D-OC
D-EC
No Surface Drainage Region
20
21
22
23
24
25
26
27
28
29
30
31
32
33
Meta
Unnamed
Bivens Arm
Alice
Clear
Unnamed
Unnamed
Unnamed
Kanapaha
Watermelon Pond
Long Pond
Burnt Pond
Wauberg
Tuscawilla
Northwest Gainesville
South Gainesville
South Gainesville
U. of F. campus
Southwest Gainesville
West of Gainesville
South of lake (27)
Northwest of Gainesville
Southwest of Gainesville
Southwest part of county
West of Micanopy
West of lake (32)
Northwest of Micanopy
South of Micanopy
1.5
3
2
2
2
2
5
1
2
1.5
2.5
5
2
3.9
1.8
70
87
4.3
7.4
2.2
5.4
84
632
23
103
64
M
E
HE
S
EC
M
D-MC
M
E-S
D-OC
D-OC
EC
E
MC
-93-
-------
Figure VII-1. Alachua County Lakes
-94-
-------
On the basis of surface runoff, the county can be divided into
three zones as shown in Figure VII-2. The southeastern third of the
county lies within the Orange Creek Basin; fourteen county lakes are in
the basin, but not all are connected by surface streams. The Santa Fe
River basin in northern Alachua County has only five lakes but consider-
able swampland. The southwestern part of the county, comprising some 300
square miles, is an area from which there is no surface outflow. The few
small streams terminate in limestone sinkholes. Fourteen lakes are lo-
cated in this region, but most of them are small ponds in the vicinity
of Gainesville.
Figure VII-2 also indicates surface distribution of geological
formations in Alachua County. A brief description of these surface
formations (summarized from Clark ejt al, 1962) is presented below. The
Hawthorne Formation is a marine deposit of Miocene Age consisting of
thick and sandy clays interbedded with phosphatic limestone. This forma-
tion is exposed in central, northern and eastern Alachua County. Higher
terrace deposits outcrop in a 70 square mile area in northern Gainesville
and north central Alachua County. These deposits are of Pleistocene Age
and consist of fine to medium sands, clayey sands, and multi-colored
clays. The Citronelle and Alachua Formations are of Pliocene Age. A
small area of Citronelle outcrops in eastern Alachua County. This is a
nonfossiliferous deltaic deposit of sand, gravel and clayey sand. The
Alachua Formation is exposed to western Alachua County and consists of
terrestrial deposits of white, gray and colored sands, clayey sands and
some multi-colored clays. Vertebrate fossils, limestone and phosphate
pebbles and boulders are scattered throughout the deposit. The Ocala
Group of Eocene Age limestones is at the surface in western and southern
Alachua County. In much of the area shown in Figure VII-2 as having the
Ocala Group at the surface, a thin layer of residual sands and clays
covers the limestone. The Ocala Group consists of coquina, hard and
soft limestones, and dolomitic limestones. The Ocala Group underlies all
of Alachua County and is the main part of the Floridan aquifer. Because
of the underlying Ocala limestones, Alachua County can be described as
generally having a karst topography. Filled and open sinks, sinkhole
lakes, solution pipes and lakes and prairies are typical of such areas,
and the county has these features in abundance. Further details about
the drainage basins and general landforms in Alachua County can be found
in Clark e_t al, (1964).
Large areas of the county are covered with slash pine for pulp
purposes, and extensive swamplands exist. Particularly in the northern
and eastern areas, the swamplands are forested with cypress and other
trees. Consequently much of the surface water in the county is highly
colored with organic exudates and plant degradation products. While
agriculture in the broad sense occupies an important place in the economy
of the county, relatively little land is devoted to annually harvested
crops. Corn and watermelons are perhaps the largest crops and are grown
in widely scattered areas. Some tobacco is grown in the northwest part
of the county, and a few orange groves are located in the south-central
-95-
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AlocKua
Formation
Ocala
Group
Hawthorn*
Formation
ij^cr ferrae*
deposits
CifroneJIe
format i on
Figure VII-2. Drainage Bas.ins and Geologic Map of Alachua County
(After Clark e_t al., 1962)
-96.
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part near Orange Lake. Considerable land is devoted to cattle grazing
In general, agriculture would seem to have little effect on the quality
of surface waters in the county. The effects of geology and surface
land use on the water quality of individual Alachua County lakes will be
discussed in later paragraphs. The physical, chemical, and biological
parameters measured in each lake are enumerated in Table VII-2.
The lakes covered in this study range in size from 0.9 hectares
(Lake Mize) to 3100 hectares (Orange Lake). Only eleven of the lakes
are larger than 100 hectares, and only four of these are larger than
1,000 hectares. Most of the lakes are quite shallow, Lake Mize being
the only significant exception. This small lake is a limestone solution
sink and has a depth of at least 25 meters. Santa Fe Lake with a maxi-
mum depth around 8 meters is the second deepest lake in the county. A
majority of lakes have maximum depths of 3-4 meters, but about a third,
including some of the larger lakes have maximum depths of 2 meters or
less. Bathymetric maps are available for only three (3) county lakes:
Newnan's, Mize, and Orange. The depths recorded in Table VII-1 are the
maximum values found at several widely scattered sampling stations on
each lake. More detailed soundings may locate deeper areas in some lakes,
but we believe the values in Table VII-1 to be closely representative of
the maximum depths.
Because of their shallow depths, few of the lakes in Alachua County
show significant thermal stratification. Lake Mize is the only known
monomictic lake, having a well developed thermocline from March to Novem-
ber (Brezonik, 1969). Santa Fe Lake may stratify at least for brief
periods in spring but data are not yet available to prove this. Even
shallow lakes will stratify briefly during calm periods of intense
warming. Such conditions occur most commonly in spring, but can occur
in fall and winter also. Evidence for temporary stratification has been
found in a number of lakes, but temperatures differ from top to bottom
usually by only a few degrees Celsius, which is insufficient to prevent
mixing by normal winds.
Conditions in three of the four large lakes (greater than 1,000
hectares) in Alachua County leave much to be desired. Relevant data
concerning trophic conditions in these lakes are summarized in Table VII-3.
Whether conditions have been affected by cultural influences is not yet
certain, but natural factors, especially geological and morphological
seem adequate to explain most of the conditions. Santa Fe Lake is the
only oligotrophic lake in this size category. Its maximum depth (8
meters) is not particularly impressive, but it is by far the deepest of
the larger lakes. An important factor relating to the lake's oligo-
trophy is its small drainage basin, the majority of which is forest. A
moderate number of cottages and homes dot the shoreline, but no other
urban or agricultural eutrophying influences are evident. Santa Fe Lake
lies wholly within the Hawthorne Formation, which contains phosphatic
clay deposits, but this circumstance is apparently mitigated by the small
drainage basin. Phosphate and inorganic nitrogen levels in Santa Fe
Lake are relatively high compared to the critical levels suggested to
-97-
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Lake depth
Lake area
Temperature
A. Water
Acidity
Alkalinity
Calcium
C.O.D.
Chloride
Color
Conductance
Fluoride
Iron
B. Sediments
TABLE VII-2
PARAMETERS MEASURED IN LAKE STUDY
Physical
Secchi disc transparency
Land use in lake basin
Shoreline development
Chemical
Magnesium
Manganese
Organic nitrogen
Ammonia
Nitrite
Nitrate
Oxygen, dissolved
PH
Orthophosphate
Total phosphate
Potassium
Silica
Sodium
Suspended solids
Total solids
Sulfate
Turbidity
Ammonia Percent volatile solids
Organic nitrogen Iron
Total phosphate Manganese
Sediment type (visual classification as peat, muck, etc.)
Biological
Algal identification and counts
Chlorophylls a, b, and £
Total carotenoids
Primary production
Species diversities indices
of algae
Visual classification of
vegetation surrounding lake
-98-
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TABLE VII-3
TROPHIC CHARACTERISTICS OF LARGE LAKES IN ALACHUA COUNTY1'2
Parameter3 Santa Fe L. Newnan's L. Orange L. Lochloosa L.
Secchi disc
Turbidity
Sp. conductance
Acidity
Alkalinity
pH
COD
Color
TON
Airanonia-N
Nitrate-N
Ortho P
Total P
Chloride
Sodium
Calcium
Iron
Manganese
Silica
Organism count
Chlorophyll a^
Primary production
2.4
5.4
48
0.6
2.6
6.5
16
130
0.44
0.22
0.0
0.001
0.11
10.4
7.5
1.3
0.02
0.008
0.11
28
5.56
13.5
0.6
5.8
60
0.9
9.0
7.6
79
490
1,13
0.02
0.0
0.006
0.05
10.8
9.8
4.0
0.06
0.003
0.68
2525
8.62
53.6
0.6
6.0
67
0.5
15
7.6
56
280
1.09
0.02
0.0
0.005
0.05
9.5
8.1
6.0
0.02
0.050
0.57
2234
9.68
43.0
0.8
7.9
90
0.5
24
8.3
55
200
1.17
0.01
0.0
0.004
0.05
10.6
9.6
10.0
0.02
0.002
0.16
5670
12.5
35.6
Lakes larger than 1,000 hectares.
Data from December, 1968, sampling; data from June, 1968 show
similar trends. Organisms counts are from June samples since counts from
December samples are not yet available. They are presented for
comparative purposes among themselves only and should not be com-
pared with the other chemical and biological results (from December).
Each number represents a single determination on a composite sample
taken from three stations in the lake.
Units for the parameters are in mg/1 except as follows: Secchi
disc transparency in meters; specific conductance in ymho cm~l;
acidity and alkalinity in mg/1 as CaCQy, pH in pH units; color in
mg/1 as P +; organism counts in numbers/ml; chlorophyll a. in mg/m3;
and primary production in mg C/m3~ hr on composite samples run in
a laboratory incubator.
-99-
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stimulate blooms in north temperate lakes, but concentrations are lower
than in the other large lakes. The biological data are all indicative of
oligotrophic conditions; color (which limits light transmissions) and
depth are probably contributing factors to this condition.
Newnan's, Orange, and Lochloosa Lakes are in the Orange Creek
drainage basin, and all show considerable evidence of eutrophy. New-
nan's Lake lies within the Hawthorne Formation outcrop, and its major
influent stream, Hatchet Creek, drains a large area of the formation
north of the lake. Water flows from the southern end of Newnan's Lake
through a creek, to a man-made canal and a meandering river into Orange
Lake. The northern half of Lake Lochloosa and most of its drainage
basin lie within the Hawthorne Formation. Orange and Lochloosa Lakes are
connected by Cross Creek, but the major flow from both lakes is through
outlets to Orange Creek to the southeast. The high trophic conditions
of these lakes are at least partially the result of edaphic considerations.
There are no major cultural sources of nutrients for these lakes although
fertilized pasture land is drained by Hatchet Creek and the towns of
Orange Lake and Mclntosh probably release some sewage into Orange Lake.
Newnan's Lake is especially peccant; its extreme shallowness must
be a contributing factor. The maximum depth shown on the bathymetric
map is 3.6 meters (12 feet), but the mean depth is under 2 meters. With
the large surface area, winds must be quite effective in mixing sediments
with the overlying water. Orange and Lochloosa Lakes are only slightly
deeper, and the geological and hydrological situation implies they are
following shortly behind Newnan's Lake on the same avenue of degradation
and extinction. All three lakes had profuse algal blooms in June of 1968.
The November standing crops were much lower though still blooming accord-
ing to Lackey's (1945) definition (500 organisms/ml). Essentially all
the criteria (see Table VII-3) reaffirm the advanced eutrophy of the
three lakes. The large lakes in the Orange Creek basin produce an abun-
dance of fish and are popular with sport fishermen. The advanced eutrophy
suggests game fishing may be in a somewhat precarious position, and take-
over by rough and trash fish could conceivably be imminent, particularly
in Newnan's Lake. Any plans to increase the man-made sources of nutrients
to these lakes should be viewed askance.
Results from the medium sized lakes are summarized in Table VII-4.
These lakes are widely scattered geographically and present an interesting
spectrum of trophic conditions. With the exception of Lake Wauberg, the
lakes are in good condition. Wauberg is in an advanced state of eutrophy
with frequent and obnoxious algal blooms. The reasons for this condi-
tion are not entirely clear. The lake is not excessively shallow
depth is at least 5 meters) and receives no urban runoff, sewage effluent
or large amount of agricultural runoff. The drainage basin seems small
and is in the Ocala Limestone Formation. In past years the lake was used
extensively for picnicking and swimming; a semi-private beach and res-
taurant were located on the lake. But the potential nutrient additions
from these sources seem inadequate to explain the present conditions.
The University of Florida now owns the land around the lake and operates
it as a camp and recreational facility for the university community.
-100-
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TABLE VII-4
TROPHIC CHARACTERISTICS OF MEDIUM-SIZE AIACHUA COUNTY LAKES '
Parameter
Seccht disc
Turbidity
Sp. conductance
Acidity
Alkalinity
pH
COD
Color
TON
Ammonia -N
Nitrate-N
Ortho-P
Total P
Chloride
Sodium
Calcium
Iron
Manganese
Silica
Organism count
Chlorophyll a_
Primary production
Altho
1.7
3.3
49
1.3
3.2
6.5
22
250
0.62
0.23
0.03
0.002
0.09
10.1
7.2
2.0
0.01
0.008
0.30
633
4.84
10.3
Cooter
1.2
4.5
63
1.4
4.8
6.9
87
250
1.12
0.45
0.01
0.003
0.16
7.6
5.7
2.2
0.01
0.009
0.81
431
21.9
87.0
Little
Santa Fe
1.3
6.3
50
3.2
1.6
5.7
31
385
0.57
0.26
0.02
0.000
0.10
9.7
7.0
1.3
0.03
0.014
0.31
150
3.28
6.6
Little
Orange
1.0
4.4
54
4.9
1.1
5.9
68
495
0.89
0.16
0.00
0.005
0.04
8.8
6.6
2.2
0.04
0.019
0.31
2352
4.11
12.7
Tuscawilla
1.2
3.3
55
6.0
12.8
6.6
52
625
0.85
0.03
0.03
0.024
0.28
7.7
6.0
4.0
0.03
0.003
2.26
341
5.76
12.2
Watermelon
3
4.0
32
2.76
0.0
4.8
23
285
0.86
0.20
0.03
0.001
0.05
6.2
4.5
0.5
0.01
0.042
0.08
125
6.44
5.33
Wauberg
0.9
10.1
59
0.0
15.7
8.3
25
125
1.71
0.09
0.00
0.005
0.15
8.7
9.4
6.0
0.00
0.004
0.17
9288
30.1
124.3
Lakes between 100 and 1,000 hectares
2
See Table VII-3 for sampling dates and units of parameters
3
Disc visible to bottom (1.6m)
-------
Lake Altho and Little Santa Fe Lake are classified as colored
oligotrophic. The two lakes are connected by an improved canal, and to-
gether with Santa Fe Lake, they form the headwater of the Santa Fe River.
Santa Fe and Little Santa Fe Lakes in a sense are one lake with two basins
separated by peninsulas which constrict the water to a short channel
several hundred yards wide. Both Altho and Little Santa Fe are moderately
deep (for this area) with maximum depths of 5 and 6.5 meters, respectively-
Both have relatively small drainage basins and no sources of cultural
enrichment other than a relatively small number of summer cottages and
homes. Little Orange Lake, in the Orange Creek basin, is somewhat simi-
lar to the above two lakes, although it is more highly colored (about 500
ppm in November) and shallower (maximum depth 3.5 meters). The lake is
surrounded by forest and is dotted with cottages, but there are apparently
no major cultural influences. The lake is somewhat difficult to classify-
Its high color implies dystrophy, but the lake has moderate nutrient
levels and a varied population of diatoms, blue-green algae and green
algae. The lake has been tentatively classified mesotrophic-colored.
Watermelon Pond is an irregularly shaped lake in the southwest
area of the county. The lake has a moderate color, and except for its
shallowness and low pH, the data conform to the usual criteria for oli-
gotrophy. Cooter Pond is in the Santa Fe drainage basin but is not
connected to the river by a permanent surface outlet. The lake is now
surrounded by pasture, but until recently groves of tung trees were cul-
tivated on the land. The general conditions now suggest mesotrophic to
eutrophic conditions. The shallowness (2.5 meters maximum depth) implies
a small capacity to assimilate more nutrients, and the lake appears to
be susceptible to further eutrophication by agricultural runoff and cat-
tle wastes. Tuscawilla Lake occupies a gently sloping depression in a
rather flat region south of Micanopy. The lake is shallow and in periods
of drought (such as spring of 1968) its area shrinks considerably. The
lake is highly colored and has a low ionic content. Nitrogen levels are
moderate but phosphorus is high, and an abundance of macrophytes is
found in the littoral zone. The chemical conditions suggest mesotrophy,
but the shallowness and extensive macrophytes imply the lake may be
approaching senescence.
Thirteen lakes scattered throughout Alachua County are in the size
range 10-100 hectares. Included are lakes in all classifications; con-
ditions relevant to trophic state are summarized in Table VII-5. Space
does not permit discussion of all these lakes, but it is pertinent to
note that three of the four Gainesville area lakes in this size class
show evidence of cultural effects. Bivens Ann receives urban runoff
from a small stream in the southern part of Gainesville and has probably
been affected by University of Florida experimental cattle farms on its
northwest shore. The lake has an interesting history; the U.S.G.S.
topographic map of Gainesville dated 1895 shows Bivens Arm connected
with Alachua Lake (Payne's Prairie), both of which were then dry. The
latter never became a (water-filled) lake again, but Bivens Arm is now
a permanent lake separated from Payne's Prairie by built-up roads.
-102-
-------
TABLE VII-5
TROPHIC CHARACTERISTICS OF SMALL LAKES IN ALACHUA COUNTY
1,2
Bivens Eliza- Haw- Hick- Jeg- Kana- Moss
Parameter Alice Ann Burnt beth thorne ory gord paha Long Lee Palatka Trout #10
H
o
V*
1
Secchi
disc
Turbidity
Sp. cond.
Acidity
Alkalinity
PH
COD
Color
TON
Ammonia -N
Nitrate-N
Ortho-P
Total P
Chloride
Sodium
Calcium
Iron
Manganese
Silica
Organism
count
Chlor a
Prim.
prod.
3
^
5.3
533
13.4
178
7.4
12
130
0.33
0.01
0.00
0.070
0.59
16.7
16.0
71
0.01
0.003
12.7
16
1.60
0
0.9
10.5
263
0.0
139
8.5
65
75
1.19
0.01
0.00
0.020
0.32
15.3
15.0
50
0.01
0.003
1.42
2600
11.0
77.5
0.9
4.9
67
3.7
15
6.8
66
620
1.87
0.47
0.00
0.039
0.36
9.6
6.5
10.0
0.04
0.007
0.64
1372
21.4
54.4
0.9
3.9
38
2.1
2.0
5.9
48
155
0.72
0.08
0.07
0.005
0.11
7.5
5.4
1.9
0.5
0.019
0.68
625
2.98
0.58
1.2
3.9
185
1.1
86
8.0
37
95
1.22
0.05
0.01
0.003
0.08
11.2
11.0
33.0
0.00
0.003
0.27
26,209
19.4
55.5
2.1
2.8
39
0.9
1.8
6.6
21
160
0.65
0.13
0.00
0.017
0.04
10.0
6.0
0.9
0.01
0.025
0.30
119
6.36
7.52
1.2
7.5
53
2.7
0.6
5.2
26
345
0.41
0.11
0.01
0.005
0.12
8.6
7.7
0.5
0.03
0.027
1.56
3824
4.28
4.26
0.6
7.2
166
4.0
70.5
7.3
78
185
3.84
0.96
0.03
0.014
0.42
8.0
10.9
19.0
0.02
0.01
0.09
11,736
9.48
26.9
3
**
3.3
16
6.4
0.0
5.1
38
240
0.89
0.05
0.02
0.001
0.04
4.4
2.5
0.6
0.01
0.033
0.18
2.56
1.42
2.0
5.4
43.0
2.8
1.2
5.9
46
278
.79
.04
.10
.010
.043
8.9
4.9
1.8
.00
.011
.017
1
3.14
12.9
3
j
3.3
22
7.4
0.0
4.8
72
185
0.86
0.14
0.00
0.002
0.08
3.8
3.1
0.4
0.01
0.005
0.71
3.34
3.36
0.6
1.8
41
8.9
1.2
5.3
64
990
1.55
0.40
0.11
0.14
0.16
7.9
6.0
1.6
0.1
0.05
1.80
10.8
10.5
1.6
4.4
44
5.0
2.5
6.0
48
305
0.81
0.06
0,01
0.027
0.10
8.8
6.6
1.7
0.02
0.012
0.35
3.29
17.4
Lakes between 10 and 100 hectares.
?
"See Table VII-3 for details on sampling dates and units of parameters.
Disc visible to bottom.
-------
Sediment cores would provide considerable information on the nature of
Bivens Arm when it was connected with Alachua Lake and the ontogeny of
the lake since it was separated and refilled. The lake may have been
eutrophic all along; but it seems likely that the above nutrient sources
have intensified conditions in the recent past.
Lake Alice has been classified senescent. This lake was once
eutrophic, but in recent years nearly all of the lake's surface has been
covered with water hyacinths. The lake is shallow, and decaying vege-
tation produces obnoxious odors. Treated sewage from the University of
Florida waste treatment plant enters the east side of the lake, but nu-
trient concentrations in the water do not reflect this source of enrich-
ment. The extensive hyacinth growths are evidently effective nutrient
removers. The lake is almost devoid of phytoplankton as a result of the
light cover provided by the hyacinths, the relatively low nutrient con-
centrations and perhaps antibiotic effects of the macrophytes. A large
volume of cooling water from the University steam plant enters Lake
Alice daily. This undoubtedly has an important effect on the lake's
biota, and probably prevents planktonic populations by a flushing effect.
In 1970 a restoration program was carried out on Lake Alice which era-
dicated all of the hyacinths from the lake surface. This program hope-
fully will improve the lake's quality of surface water.
Lakes Kanapaha and Hawthorne are also culturally enriched. The
former lake is connected with Kanapaha Sink, the terminus of Hogtown
Creek in Gainesville; the latter lake receives some sewage from the town
of Hawthorne. Burnt Pond is apparently naturally eutrophic. Its shallot"
ness indicates the lake may not be far from the senescent state. Most
of the other lakes in this size category are in relatively good condition.
High organic color and relative isolation from urban and agricultural
development characterize these lakes.
Nine of the lakes in this survey are smaller than 10 hectares.
There are also innumerable small ponds (one hectare or less) scattered
throughout the county (particularly around Gainesville). These are
usually quite shallow and can hardly be considered as lakes in the usual
sense of the word. The nine lakes chosen in this survey include all
the large lakes in this size category (i.e. lakes between 3 and 10 hec-
tares) and a few smaller lakes chosen because of their unusual charac-
teristics or potential significance in a broad recreational sense. The
trophic conditions of these lakes are summarized in Table VII-6. Lake
Mize is perhaps the most interesting of these small lakes, because of
its great depth (about 25 meters). The lake exhibits the usual charac-
teristics of dystrophy--high color and acidity, low pH, few organisms,
etc. The lake is remarkably similar morphologically and chemically to
Lake Mary, Wisconsin, except for the latter*s mesomixes. Lake Mize is
located in the University of Florida Austin Gary Memorial Forest, which
one might presume would augur the preservation of this unusual lake.
Unfortunately an enclosure for maintaining and raising waterfowl was re-
cently allowed to be built on the shore, and now over fifty ducks
contribute untreated excrement directly to the water.
-------
TABLE VII-6
TROPHIC CHARACTERISTICS OF PONDS AND LAKELETS IN ALACHUA COUNTY
1,2
Parameter
Secchi disc
Turbidity
Sp. cond.
Acidity
Alkalinity
PH
COD
Color
TON
Ammonia -N
§ Nitrate-N
g Ortho-P
yx Total P
Chloride
Sodium
Calcium
Iron
Manganese
Silica
Organism
Count
Chlor a
Prim. prod.
Clear
0.8
10.0
106
0.0
27.6
8.9
44
345
1.38
0.02
0.00
0.007
0.17
8.2
7.0
10.0
0.04
0.005
1.68
5,896
11.4
69.1
Clearwater
1.8
2.8
33
1.5
0.8
5.4
14
25
0.59
0.10
0.00
0.003
0.05
7.4
5.2
0.7
0.01
0.023
0.14
9
3.32
0.33
Meta
1.4
6.5
86
1.4
27.4
7.6
40
90
0.83
0.09
0.00
0.001
0.06
8.2
7.0
10.0
0.00
0.003
0.14
15,160
5.51
3.59
Mize
1.0
3.9
45
5.8
1.4
5.6
34
260
0.51
0.26
0.01
0.005
0.09
9.2
5.3
0.8
0.05
0.010
0.98
88
24.2
7.46
Still
#21
0.8
10.6
275
0.3
128
8.2
50
165
1.33
0.02
0.00
0.004
0.25
17.7
15.0
48
0.00
0.003
2.91
10,840
39.0
235
#25
3
0.9
106
0.0
50.4
8.3
17
75
0.73
0.07
0.03
0.001
0.06
3.4
3.1
20.0
0.00
0.016
0.57
163
0.18
6.06
#26
0.9
38
9.8
0.6
5.3
29
500
0.74
0.03
0.01
0.004
0.12
9.1
6.3
0.9
0.05
0.015
1.60
303
6.86
2.09
#27
1.8
3.9
43.0
9.0
5.7
6.0
28
220
0.56
0.04
0.00
0.012
0.20
7.7
5.6
2.1
0.02
0.014
0.66
18
12.7
41.0
Still
Pond
.7
3.8
40
1.3
.6
6.0
20
70
.58
.07
.02
.006
.016
7.8
5.5
1.0
.00
.004
.002
«-.
1.81
0.2
Lakes smaller than 10 hectares.
See Table VII-3 for details of sampling dates and units of parameters,
Disc visible to bottom.
-------
Lake #27 (unnamed) is unusual in that it is completely covered
with duckweed (Lemna) normally indicative of high nutrient conditions.
The lake is isolated from urban and agricultural effects and otherwise
exhibits oligotrophic characteristics. The lake is moderately deep
(for this area)--maximum depth is at least 5 meters. There does not
seem to be a satisfactory explanation for the extensive duckweed growth
in this lake and its virtual absence in all the other lakes of this sur-
vey. Clear lake was evidently named before the onset of a eutrophic con-
dition which contradicts its name. The lake is surrounded by homes with
septic tanks and has become eutrophic only in recent years (Furman, per-
sonal communication). An extremely dense Anabaena bloom was present in
the June, 1968, sample and the lake oscillates between relatively clear
and bloom conditions. Lake Meta (in northwest Gainesville) also shows
some signs of cultural enrichment from surrounding homes, but to a
lesser extent.
Even cursory inspection of the chemical and biological results
obtained reveals graphic disparities in trophic conditions among the
lakes. In fact inspection of the lakes themselves illustrates this in
a dramatic albeit crude way. An attempt to classify the lakes according
to the usual trophic types is included in Table VII-1. Some geographi-
cal patterns in trophic type are evident but not altogether conclusive.
Lakes in the Santa Fe River basin are oligotrophic and somewhat colored.
Many of the small lakes in the Orange Creek basin are also oligotrophic
and most are highly colored, but the large lakes are eutrophic. Lakes
in the southwestern part of the county are quite varied with respect to
trophic levels. Some of the small lakes in urban and suburban Gaines-
ville show evidence of eutrophy; cultural influences may have exerted
some stress on these lakes.
The trophic criteria do not give clear indications of trophic
state in all cases. Some of the smaller lakes have both oligotrophic
and eutrophic characteristics, and many lakes have dystrophic character-
istics along with oligotrophic or eutrophic conditions. The lakes with
oligotrophic and eutrophic criteria are classified as mesotrophic; Lake
Elizabeth and Cooter Pond are examples. These lakes may be in a trans-
itional state between the two trophic levels. Alternatively, these may
be examples of the inadequacy of trophic criteria developed for temper-
ate lakes when applied to subtropical lakes. The inadequacy of the
dystrophic classification is amplified by the results from this study.
Over half of the lakes show some signs of dystrophy, i.e. high color,
low pH, low ionic solids. However, high color is not always correlated
with other criteria for dystrophy. Some colored lakes have neutral or
alkaline pH (e.g. Lake Kanapaha) or high calcium and alkalinity (Lake
#21). The range of nutrient concentrations and plankton in these lakes
is from unproductive to hypereutrophic. It is obvious that one class
(dystrophy) is insufficient to describe all these lakes, even though
each has several criteria indicating dystrophy. Hansen's (1962) dicho-
tomic classifications where lakes are classified as colored or clear an
each of these has the full range of trophic states (oligotrophy to eu-
trophy) are an improvement over classical typology. However, eutrophi-
.106.
-------
cation in colored and clear lakes may proceed along different courses,
and trophic states in the two classes may not be strictly parallel
(e.g. different biota and trophic structures may result from eutrophica-
tion in the two classes). Lakes showing partial dystrophy in this study
have been classified colored-oligotrophic, colored mesotrophic, etc.,
as appropriate. A few lakes with rather extreme dystrophic conditions
(e.g. Lakes Mize, Palatka, Jeggord, Long Pond) have been tentatively
classified as dystrophic along with an alternate classification such as
colored-oligotrophic. These are subject to change as the classification
scheme becomes further developed and refined.
The shallow lakes present especially difficult problems in
classification. Lakes with depths of two meters or less are suscepti-
ble to take-over by macrophytes like hyacinths. Thus they could quickly
become swamps or bogs and must be near the senescent stage. The present
trophic state of these lakes range from dystrophy (Palatka), mesotrophy
(Tuscawilla), hypereutrophy (Bivens Arm) to senescence (Alice). It is
not clear whether a lake like Tuscawilla has already been through a
eutrophic stage and is now in a decreased state of production heading
toward senescence or it never reached eutrophic conditions and will pass
into senescence without doing so. If lake classifications are to imply
anything regarding a lake's ontogeny, and its probable future develop-
ment, it is important that such questions be resolved. A corollary to
the problem of shallow lakes is the problem of lakes with extensive
shallow areas but some deeper holes. For example, Newnan's Lake has
large areas with a depth of 1 meter or less but has several small regions
nearly 4 meters deep (mean depth is about 2 meters). The shallow areas
could give rise to extensive growths of rooted or attached macrophytes
and develop into swamp or bog, which would indicate senescence, but the
deeper areas could remain lacustrine for much longer. In fact, consider-
able difficulty has been encountered in controlling water hyacinths
(not an attached plant) in recent years, which implies the lake, or a
large portion of it could become senescent in the near future.
The data in Table VII-3 to VII-6 show a number of interesting
correlations. Figure VII-3 indicates a positive correlation between
sodium and chloride concentrations in the 33 lakes, implying a common
origin for the two ions. However, the estimated line of best fit de-
viates significantly from the theoretical line for NaCl dissolution with
an excess of sodium over chloride. Most of the chloride presumably
originates as sodium chloride, probably from atmospheric precipitation
(from marine aerosols) and cultural sources. But other salts and
weathering of clays must also act as sources of sodium. High sodium
and chloride concentrations correspond with lakes having known pollu-
tion sources (e.g. Alice, Bivens Arm, and Hawthorne).
Calcium and bicarbonate alkalinity are highly correlated (Figure
VII-4). The slope of the line of best fit approaches the theoretical
line for dissolution of calcium carbonate:
CaC03 + C02 + H20 > Ca+2 + HCO,
-107-
-------
18
16
14
12
E
&- 10
Theoretical /
for NaCI ,
r /
175
150
| 10°
2
< 50
25
0
10
8 10 12
Sodium ^ppin;
Figure VII-3
14
20 30
40 50 60
Calcium (ppm)
Figure VII-4
16 18
70 80
-108.
-------
implying this to be the source of calcium and alkalinity in the lakes.
Most of the lakes have low concentrations of these ions; only nine lakes
have calcium concentrations of 10 ppm (as Ca) or greater. The major
natural sources of water for the lakes in the county are atmospheric
precipitation, and surface and sub-surface runoff through perched water
tables in the sandy soil; hence the low calcium concentrations. High
calcium suggests a lake receives ground water from the Floridan aquifer
(a limestone stratum), which means the lake is either spring-fed or re-
ceives waste water from supplies using well water from the aquifer.
Most of the lakes with high calcium have known sources of waste water
(e.g. AlicejBivens Arm, Clear, Kanapaha, and Hawthorne). Since high
nutrient concentrations are associated with such waters, these lakes
are highly enriched. Thus for most of the lakes in Alachua County,
calcium ion appears to be a good indicator of cultural eutrophication.
The relatively high calcium content of Lochloosa Lake probably results
from Magnesia Spring, which drains into Lochloosa Creek about 5 miles
north of the creek's confluence with the lake.
There was little apparent correlation between total nitrogen and
total phosphate in the December, 1968, sampling of the 33 lakes as indi-
cated by the scatter diagram in Figure VII-5. However, lakes with the
most extreme N/P ratios are seriously polluted (e.g. Alice and Kanapaha)
and there are some indications that lakes in a particular region have
similar N/P ratios. For example, lakes in the Santa Fe River headwaters
(Altho, Santa Fe, Little Santa Fe) have similar ratios which are gener-
ally higher than the larger lakes in the Orange Creek Basin. The dashed
line in Figure VII-5 indicates the usually quoted optimum N/P ratio
of 15:1 by atoms for algal growth. Points below the line suggest an
excess of nitrogen relative to phosphorus; most of the lakes belong in
this category.
Chemical oxygen demand (COD) and color show no correlation for
the 33 lakes (Figure VII-6). Evidently there is a considerable varia-
bility in non-colored organic matter in the waters. The highest color/
COD ratio was 17 (Lake #26). Eight of the lakes have ratios of 10-13
and the remainder of the waters have lower ratios, suggesting large
amounts of non-colored organic matter. There is some evidence that low
color/COD ratios indicate organic pollution; for example, Bivens Arm
had the lowest color/COD ratio (1.15), but other apparently unpolluted
lakes (e.g. Palatka) also had low ratios (2.6).
A plot of turbidity versus the inverse of Secchi disc reading
(Figure VII-7) also shows considerable scatter, implying other factors
control Secchi disc visibility. Inspection of the data suggest color
has an important effect; Trout Lake, with a color of 990 ppm, had the
highest ratio (0.93) of (Secchi disc)1/turbidity. A multiple regression
of Secchi disc against turbidity and color, after removal of Secchi disc
readings affected by shallow bottoms, would probably account for most
of the variance.
-109-
-------
I 0.6
0 0.5
s.
o
O
0.4
o.:
o.
Alice
* X
X
X
X
x
/./
X
X
«
X
X
X
X
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Total Nitrogen (ppm as N)
Figure VII-5
Kanapaha i
4.5 i.O
£
*rt
O
§.
£.
7
6
800
700
600
500
400
300
200
100
)
J990
_
""
""
'
.
*
i i tilt 1 1 1
° 10 20 30 40 50 60 70 80 90 100
COD (ppm)
Figure VII-6
-no-
-------
« 2.0
1.6
.o
'u>
>
8
u
o
V
1.2
Trout L.
. . /
v
6 8 10 12
Turbidity (ppm as SFCfc)
Figure VII-7
14
>H
-1
X
|
iry Production
E
£
160
140
,»
100
80
60
40
20
0
-
(235)
.
"
-
(3.84)
MM
*
* . . % * * *
1*1 L 4. i i i i ii i
0.5 1.0 1.5 2.0 2.5
Ton (mg/l)
Figure VII-8
-111-
-------
A wide range of primary production and chlorophyll a data are
encountered in the 33 lakes. Rates of the former ranged from negligible
(Lake Alice) to 235 mg C/m^-hr (Lake #21). In order to facilitate com-
parison of rates in the lakes, all incubations were carried out under
constant light and temperature conditions in a laboratory incubator. In
general, highest rates of primary production are associated with lakes
showing eutrophic chemical characteristics. However, there does not
seem to be any simple quantitative relationship between primary produc-
tion values and concentrations of nutrients. For example, Figure VTI-8
shows the scatter which occurs when primary production is plotted vs
total organic nitrogen. Plots of primary production vs inorganic nitro-
gen and phosphate show similar scatter.
There is also no simple relationship between primary production
and depth (Figure VII-9), as Rawson (1955) found for the Great Lakes
and some Canadian lakes he studied. There is some uncertainty concern-
ing the meaning of depths used to plot Figure VII-9 (see discussion
above). Since bathytnetric maps are not available for these lakes, mean
depths are unknown; maximum depths for most lakes are probably somewhat
greater than the values used here. Some of the variance may be removed
with accurate measures of mean depth, but primary production values
would still seem to be grouped into classes rather than along any linear
or curvilinear relationship. The horizontal dashed line in Figure VII-9
represents an arbitrary division between high and low productivity lakes.
Points above this line correspond with lakes classed as mesotrophic or
eutrophic. The dashed vertical line represents an arbitrary division
between deep and shallow lakes; most of the lakes would be classified
as shallow productive or shallow unproductive on this basis.
Chlorophyll a_ concentrations also show a qualitative correlation
with other criteria for trophic state (i.e., high chlorophyll a_ con-
centrations are associated with lakes classified as eutrophic or meso-
trophic). However, quantitative correlations with nutrient concentrations
are not evident. The relationship between chlorophyll a_ and primary
production also shows considerable scatter (Figure VII-10), although
there would seem to be a significant correlation between the two para-
meters.
Lakes in the Oklawaha River Basin. The region northwest of
Orlando consists of rolling hills occupied by thousands of acres of
citrus trees. The area has an abundance of lakes situated in its val-
leys, including a chain of large lakes in the southern part of the
Oklawaha River Basin. These lakes have been popular for recreation and
in the past at least one (Lake Apopka) was famous nationally for bass
fishing. The quality of several of the lakes has declined radically in
recent years and concern has been expressed regarding the cultural eu-
trophication of the entire chain. Implicated as an important nutrient
-112-
-------
I4U
»
CO
5 100
f
^ 80
c
*r
o
3 60
ct
1 4°
£
Oft
ZU
250'
1
^ 200
-f
CO
§ 1?5
f
1 15°
g 125
<£
0s 100
et
75
50
25
0
C
(235)
t
-
.
*
-
I
t_^w
1 . ^ ' (22)
i / * i f i i i i i i
12 34567891-
Depfh (Meters)
Figure VII-9
-
x
s
/
'
X
xx
x«x
/
X"
. x '
X
X-
X .
X
xx? *
.%! i 1 I ? | | | |
) 4 8 12 16 20 24 28 32 36 40
Chlorophyll a (Mg/M3)
Figure VII-10
-113-
-------
source is agricultural runoff-primarily from vegetable farms in reclaimed
marsh and wetlands, but also from citrus groves; domestic waste effluent
from towns on the lakes' shorelines and waste from citrus concentrate
processing plants are also important nutrient sources.
The location of the lakes included in this survey is shown in
Figure VII-11 and physical data on the lakes is summarized in Table VII-7-
TABLE VII-7
PHYSICAL CHARACTERISTICS OF LAKES IN OKIAWAHA BASIN
Lake
Apopka
Dora
Eustis
Griffin
Harris
Weir
Area
(ha)
12,200
2,060
2,740
3,455
7,090
2,420
Depth
(m)
2
3.5
5
3
5.5
7.5
Surface
Temp.
°C
19.8
16.7
24.9
19.8
22.9
25.7
Bottom
Temp.
°C
19.6
16.6
24.7
18.9
20.0
24.0
Lake2
Type
HE
HE
E
E
E
M-E
Maximum depth found during sampling. In the case of Lake Apopka,
this value also represents the mean depth; maximum depth of this lake
is 6 m in a small hole near the southern shore (see Schneider and
Little, 1968) for a bathymetric map). A map of Lake Weir is also
available (Kenner, 1964) and indicates a maximum depth of 10 m in a
small hole near the southern shore.
2
See Table VII-1 for list of abbreviations.
Lake Apopka is the largest of these lakes, and also the first lake in
the Oklawaha chain. This lake is probably the most famous of the chain*
but is now considered as the furtherest advanced in the eutrophication
process. The lake has been the subject of numerous investigations and
reports (see Burgess, 1964; Huffstutler e_t al^ 1965; Schneider and
Little, 1968 for details on the recent history of the lakes). Lake
Apopka drains into Lake Dora through the Beauclair Canal, and the
latter lake drains into Lake Eustis. Lake Harris also drains into Lake
Eustis, which drains into the last important lake of the chain, Lake
-------
101 234
Miles
LAKE J0EUSTIS
EUSTIS
LAKE A POPKA
34
\
LEESBUR6
WINTER GARDEN
Figure VII-11: Location of Lakes in Lower Oklawaha River Basin.
-115-
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Griffin. While not directly in the chain, Lake Weir, about 10 miles
northwest of Lake Griffin, is within the Oklawaha drainage basin. None
of these lakes has received the attention accorded to Lake Apopka, but
some prior studies are available. The Florida Game and Fresh Water Fish
Commission is performing a detailed study on the trophic states of
LakesApopkas Eustis, and Weir, and their data will be useful in develop-
ing and analyzing trophic criteria.
The six lakes were sampled for the chemical and biological
parameters shown in Table VII-2. The results are summarized in Table VII"
8. The trophic characters of the lakes are revealed quite unambiguously
by these initial results. All the lakes in the Oklawaha chain are eu-
trophic. Lake Weir is in considerably better condition than the lakes
in the chain, but it is on the border between mesotrophy and eutrophy.
Lakes Apopka and Dora have the most advanced cases of eutrophy; all
vant chemical and biological data indicate a high degree of enrichment
and productivity. The shallowness of Lake Apopka implies the lake could
pass from hypereutrophy into senescence if macrophytes (e.g. hyacinths)
are allowed to take over. Lakes Eustis and Griffin present slightly
improved characteristics compared to the first two lakes. The chemical
and biological conditions of Lake Harris are the best of the five lakes
in the chain. The trophic criteria definitely indicate a eutrophic
state, but perhaps not the hypereutrophy of the other lakes. Perhaps
some of the water quality improvements in Lakes Eustis and Griffin re-
sult from dilution of enriched Lake Dora effluent by relatively nutrient
poor Lake Harris water.
The water chemistry of Lake Weir differs considerably from the
other lakes. Alkalinity and hardness are low in Lake Weir and pH is
near neutrality. Major cations and anions are moderate to low and a
specific conductance of 135 jjmho cm-1 reflects this fact. Lakes in the
chain have high alkalinities and hardness and pH values near 9 or above-
Major ion concentrations are high and specific conductance ranges from
230-335 ymho cm"1. The correlation between high trophic level and high
concentrations of major ions in these lakes and relatively low trophic
level and low ionic content in Lake Weir might imply that eutrophica-
tion involves an increase in dissolved solids and a change from soft to
hard water. In fact dissolved solids has been considered a trophic
criterion and was used as such by Beeton (1965) and others. A certain
degree of correlation would be expected between increasing nutrients
and increasing dissolved solids where enrichment results from domestic
waste effluent and the town's water supply is hard ground water. This
is the case with Lake Apopka, where the city of Winter Garden obtains
its drinking water from wells. The meager background chemical data on
the lake indicate some increases in dissolved solids and hardness in
the period of record, but the lake water was relatively hard and high
in dissolved solids over 40 years ago. Black and Brown (1951) reported
a chemical analysis of Lake Apopka from August, 1924, made by the U. S.
Geological Survey. Table VII-9 compares their results for major ions
with the results from this study. While the lake was probably quite
productive in 1924, serious degradation in water quality has occurred
-116.
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TABLE VII-8
CHEMICAL AND BIOLOGICAL CONDITIONS
IN OICLAWAHA LAKES, OCTOBER, 1968'
Constituent2 Apopka Dora Harris Eustis
Griffin Weir
Diss. 0,
Cond,
PH
Alkalinity
COD
Color
Secchi Disc
Turbidity
Sus. solids
TON
NH,-N
Ortho PO4
N08-N
NOa-N
Total P
Si03
Fe (total
Mn (total)
Ca«
Mr2
Na*
K.*
ci-
SO4-
Chora
Prim. prod.
11.2
330
9.5
126
113
30
0.3
27
43
3.8
0.18
0.016
0.004
0.09
0.24
6.4
T
T
25.1
14.7
11.7
2.9
21
10.2
34.1
0.386
11.4
335
9.5
130
157
43
0.3
28
77
5.3
0.17
0.108
0.005
0.11
0.39
0.05
0.01
0.003
30.5
14.2
18.1
3.4
22.3
12.3
72.1
1.02
9.7
230
8.8
91
48
13
0.8
20
13
1.7
0.19
0.010
0.004
0.05
0.035
3.4
0.01
0.006
23.1
6.1
9.7
0.9
12.8
4.9
17.7
0.037
8.78
275
8.9
104
112
28
0.6
25
46
4.1
0.20
0.014
0.006
0.24
0.22
1.4
0.01
0.005
26.3
10.7
14.5
2.4
18.7
7.1
33.1
0.274
8.4
290
8.9
112
78
25
0.5
28
27
3.0
0.18
0.014
0.007
0.09
0.20
0.40
0.01
0.003
28.9
9.6
14.0
2.1
17.5
6.7
45.4
0.183
7.60
135
7.2
15.1
25.
5
1.2
3
22
0.97
0.25
0.006
0.004
0.05
0.021
0.34
T
0.005
1.4
3.1
15.5
1.0
26.8
4.8
8.4
0.011
1 Results are average values for composite samples from three stations in each
lake.
* Chemical species in mg/1 except as follows: alkalinity in mg/1 as CaCO3, nitro-
gen .species in mg N/l, phospnorus species in mg P/l, color in mg/1 as Ft.
specific conductance in /anno cm-i, Secchi 'disc visibility in meters, chlorophyll
a in mg/ms.
Primary production in mg C fixed/1-hr. Composite lake-water samples were
run in a laboratory incubator.
-117-
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TABLE VII-9
COMPARISON OF MAJOR IONS IN LAKE APOPKA IN 1924 AND 1968
Constituent
Total dissolved solids
Calcium
Magnesium
Sodium and Potassium
Iron
Bicarbonate
Sulfate
Chloride
Silica
19242
129
18
8.3
11
0.17
89
4.5
17
6.7
19683
184
25.1
14.7
13.4
T «0.01)
152
10.2
21
6.4
Results in mg/1; potassium expressed in terms of sodium (Na).
2
From Black and Brown (1951); original data by the U.S. Geol. Surv.
(Water Supply Paper 596-G), Washington, D.C. (Collins and Howard,
1927).
3
Data from this study.
only in the last 15-20 years. Thus increasing hardness and dissolved
solids would not seem to be a necessary feature of cultural eutrophi-
cation. Quite possibly eutrophication in Lake Weir may proceed along a
different course not involving increases in solids and hardness--as has
apparently been the case with lakes in the Orange Creek Basin (e.g.
Newnan's Lake).
It is difficult to draw firm conclusions regarding trophic state
from one set of samples. Various parameters may respond to seasonal
changes differently in each lake. With this limitation in mind, we
would tentatively systematize the trophic conditions of these lakes in
the following sequence:
-118-
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Lake Apopka = hypereutrophicnear senescence
Lake Dora = hypereutrophic
Lakes Bustis and Griffin = eutrophic
Lake Harris = moderately eutrophic
Lake Weir = mesotrophic to moderately eutrophic
The above sequence is somewhat relative since it is difficult to compare
lakes in different regions in a quantitative manner. Eutrophy in Lake
Apopka is considered more advanced than in Lake Dora because of the ex-
treme shallowness of the former lake. The chemical and biological
results are similar for the two lakes; in fact Lake Dora had more ex-
treme values for some trophic criteria. But it is somewhat deeper and
because of this perhaps more amenable to restoration.
Conclusions. The results obtained in this phase of the
eutrophication study substantiate the complexities involved in defining
and quantifying lacustrine trophic states. The chemical and biological
information obtained on each lake has enabled us to classify the lakes
qualitatively as oligotrophic or eutrophic, etc. The correlations among
different trophic indicators are generally good for these lakes--on a
qualitative basis, but simple regressions of one criterion versus another
in all cases showed large amounts of scatter or unexplained variance.
Trophic state and the interrelations among trophic criteria are multi-
variate functions. Quantification of these phenomena requires more
sophisticated mathematical analysis than those employed above. Stochas-
tic modeling procedures seem to be particularly appropriate to the
problem of quantifying trophic indices with masses of data collected
from different lakes. Multivariate techniques, such as canonical corre-
lation, multiple discriminant analysis and factor analysis (principal
component analysis), were used to synthesize quantitative measures of
trophic state for sub-tropical lakes. This is discussed in the following
section.
Quantitative Trophic State Study
In establishing the trophic state index the apparent response
of lakes to nutrient enrichment has been envisioned as a multi-dimen-
sional hybrid concept described by several physical, chemical and
biological trophic state indicators and appropriate multivariate sta-
tistical methods have been used to analyze the relationships between
nutrient enrichment and trophic state. One aspect of these studies was
concerned with formulating a Trophic State Index (TSI) that would pro-
vide a means for quantifying trophic state on a numerical scale. Such
-119-
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an index is desirable for the following reasons: (1) a TSI would
facilitate identification and comparison of lakes, (2) in the dynamic
process of trophic state change, a TSI provides a method for deter-
mining the trophic state of a lake at any particular time and evaluation
of the index over time should provide information on the direction and
rate of lake succession, (3) a TSI should be used in quantifying the
response of the lake ecosystem and its environment (watershed conditions
influencing nutrient enrichment). Such relationships should in turn be
useful in lake-basin management models, where it may be of particular
interest to know how much nutrient enrichment will cause significant
change in lake water quality.
In formulating the TSI seven trophic state indicators were
considered as describing the concept of trophic state; viz. primary
production (PP), chlorophyll a (CHA.), total phosphorus (TP), total or-
ganic nitrogen (TON), conductivity (COND), inverse Secchi disc transpar-
ency (1/SD), and the inverse of a cation ration fCa + Mg. (1/CR)
W + K '
(after Pearsall, 1922). Inverses of the last two parameters were used
so that each indicator exhibited a positive response to eutrophication
(i.e. the indicator value increases with increasing eutrophy). Data for
these indicators had been obtained from an extensive one year study of
the chemical, biological, physical, and morphometric characteristics of
fifty-five Florida lakes contained within the areas indicated in Fig-
ure VII-12. The means, standard deviations, and the correlation matrix
between the seven indicators are summarized in Table VII-10. A princi-
pal component analysis was performed on the correlation matrix and the
first principal component extracted. The first principal component was
modified by adding a constant to prevent negative values and interpreted
as the Trophic State Index. The method of principal component analysis
is described by Morrison (1967). The formula for evaluating TSI is
given by:
TSI - .919(1/SD) + .800(COND) + .896(TON) + .738(TP) +
.942(PP) + .862(CHA) + .635(1/CR) + 5.190 (1)
where the terms in parentheses refer to standardized indicator values
since the units of the indicators differ. Standardization involves
the subtraction of the mean value of the indicator from the raw data
value and dividing by the indicator standard deviation. The appropriate
means and standard deviations are from Table VII-10. Calculation of
the TSI then is a straight forward process of substituting the stan-
dardized trophic state indicator values for a lake into equation (1).
The TSI's were calculated for fifty-five Florida lakes and ranked in
descending order of magnitude in Table VII-11. In addition, the TSI's
of Lake Tahoe, Lake Erie, and Lake Superior were calculated and in-
serted in Table VII-11. Secchi disc values influenced by organic color
were color corrected by a multiple regression procedure not described
here.
-120-
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30° -00'
STUDY AREAS
.EGENO
STUDY AREA
VICINITY MAP SHOWING MAJOR
LAKE STUDY AREAS
BEACH
VILLC
FIGURE VII-12
LOCATION MAP SHOWING MAJOR LAKE STUDY AREAS
-121-
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TABLE VII-10
MEANS, STANDARD DEVIATIONS, AND CORRELATION MATRIX
FOR SEVEN TROPHIC STATE INDICATORS
Standard
o
Indicator Mean Deviation
L/SD .84 .77
COND 93.1 101.3
TON 1.02 .82
TP4 .125 .177
PP 44.8 82.3
CHA 16.9 19.8
1/CR 1.47 1.63
Correlation Matrix:
1/SD COND TON TP4 PP CHA 1/CR
1/SD 1.000 .617 .880 .542 .927 .784 .502
COND 1.000 .582 .762 .654 .540 .560
TON 1.000 .500 .890 .788 .474
TP4 1.000 .576 .553 .440
PP 1.000 .859 .478
CHA 1.000 .402
1/CR 1.000
a
Key to indicator abbreviations in text
-122-
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TABLE VII-11
FLORIDA LAKES RANKED WITH RESPECT TO THE TROPHIC STATE INDEX (TSI)
Lake
TSI
(a) HYPEREUTROPHIC GROUP (> 10.0)
Lake Apopka"(34)a 22.1
Lake Dora (35) 18.5
Unnamed 20 (20) 18.5
Biven's Arm Lake (23) 14.7
Lake Griffin (38) 13.7
Lake Kanapaha (28) 13.5
Lake Alice (22) 10.7
Lake Bustis (37) 10.5
(b) EUTROPHIC GROUP (7.0-9.9)
Lake Erie* 9.8
Lake Hawthorne (8) 9.1
Clear Lake (24) 8.8
Burnt Pond (31) 8.3
Lake Wauberg (32) 7.4
Lake Newnans (17) 7.1
(c) MESO-EUTROPHIC GROUP (4.0-6.9)
Unnamed 25 (25)
Lake Harris (36)
Unnamed 27 (27)
Cooter Pond (5)
Lake Lochloosa (14)
Lake Tuscawilla (33)
Calf Pond (19)
Orange Lake (15)
Lake Mize (18)
6.4
6.3
5.8
5.3
5.2
4.8
4.6
4.3
4.2
(d) OLIGO-MESOTROPHIC GROUP (2.0-3.9)
Lake Superior*
Watermelon Pond (29)
Lit. Orange Lake (9)
Lake Weir (39)
Palatka Pond (16)
Lake Elizabeth (6)
Unnamed 10 (10)
aLake number in parentheses
Included for comparison
3.7
3.6
3.4
3.3
3.2
3.2
3.2
Lake TSI
Seville's Pond (26) 3.1
Lake Meta (21) 3.1
Lake Jeggord (12) 2.8
Long Pond (30) 2.8
Lake Moss Lee (11) 2.8
Lake Clearwater (7) 2.6
Lake Altho (4) 2.5
Hickory Pond (3) 2.5
Lake Santa Fe (1) 2.5
Lake Suggs (51) 2.3
Lake Lit. Santa Fe (2) 2.3
Lake Adaho (48) 2.2
Wall Lake (46) 2.1
Lake Winnott (53) 2.0
(e) OLIGOTROPHIC GROUPS (< 2.0)
Still Pond (13) 1.9
Kingsley Lake (40) 1.9
Lake Geneva (44) 1.8
Lake Tahoe* 1.7
Lake Gallilee (55) 1.6
Lake Anderson-Cue (50) 1.5
Swan Lake (45) 1.5
Lake Brooklyn (43) 1.5
Lake McCloud (49) 1.5
Cowpen Lake (54) 1.5
Long Lake (52) 1.3
Sand Hill Lake (41) 1.3
Magnolia Lake (42) 1.3
Lake Santa Rosa (47) 1.3
-123-
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In order to determine logical groups of lakes whose members
possess similar trophic state characteristics the fifty-five lakes were
subjected to a cluster analysis considering the seven trophic indicators.
The principles and methods of cluster analysis are described by Sokal
and Sneath (1963). The hierarchal clustering patterns (dendrograms) are
shown in Figure VII-13. One dendrogram is for the colored lakes and the
other for the relatively clear lakes. (It was found for Florida lakes
that fundamental distinctions could be made between lakes on the basis
of organic color as suggested by Hansen (1962)). The value of the ob-
jective function on the abscissa of the dendrograms is used as a measure
of similarity. In general, an increase in the value of the objective
function at which a function is made represents a decrease in similarity
among lakes of the newly formed group, thus lakes of greatest similarity
are joined first and so on.
Several groups of lakes were interpreted in terms of classical
trophic-state nomenclature as: Groups 1, 2, and 3 combined - oligo-
mesotrophic, Groups 4, 5, and 6 combined meso-eutrophic, Group A -
oligo-trophic, Group B - mesotrophic and Group C - eutrophic. The ver-
tical dashed lines in Figure VII-14 were used for the discriminant
analysis phase of the studies.
Using the groups of lakes delineated by the cluster analysis,
five tentative TSI ranges were separated and interpreted. These ranges
and groups are indicated in Table VII-11.
Some features of the TSI ranking in Table VII-11 deserve mention.
Lake Alice, a lake with profuse growth of water hyacinths, has been
ranked as hypereutrophic whereas on the basis of plankton productivity
alone, it may well be considered as being oligotrophic. However, in
the TSI, the high nitrogen, phosphorus, and conductivity indicator values
were sufficient to counteract the low primary production and chlorophyll
a indicator values. Anderson-Cue Lake (as previously discussed) has
been subjected to artificial nutrient enrichment for three years, but
has demonstrated little response with respect to the seven trophic state
indicators, with the exception of chlorophyll a. As previously pointed
out the lake has responded to increased periphyton growths. Because none
of the seven indicators are sensitive to this response, the lake still
registers a low TSI (1.5), which is identical to the TSI of McCloud
Lake (the control).
The TSI formulated for Florida lakes appears to apply reasonably
well in ranking other lakes; for example, Lake Tahoe, Lake Erie, and
Lake Superior have been positioned where one might expect them to fall*
The TSI, undoubtedly requires further testing and refining and it may
well be that some trophic state indicators could be added or deleted
from the index formula [Equation (1)] . However, the multivariate
methods used for deriving the TSI and for grouping lakes seem most lo-
gical and hold considerable potential as tools for studying other aspects
of the eutrophication process.
-124-
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VALUE OF THE OtUECTIVE FUNCTION
-6OO -500 -10O -300 _ -SCO
(41) SANO HILL
(42) MAGNOLIA
(SlJGAtLICE
( ADAliO
150 suces
(9) LIT. ORANGE
(t2) JEGCORO
(31) BURNT
CS3) TUSCftWILLA
(5) COOTER
(19) CALF
(1£) PAUATKA
t>0) LOWS POHO
(zc) SEVILLE'S
(27J HO. £7
(17) NEV/NANS
08) HIZE
(201 KANAPAMft
FIGURE. VIJ-13
DENDOGRM OF COLORED (UPPKR) AND CLEAR (LOWER) LAKES CLUSTERED
WITH RESPECT TO SEVKN TROPHIC INDICATORS
-125-
-------
10.0
Z
O
e
o
I
1.0
i>>
o
o
t
EUTROPHIC '
(VOUEWYEIDE.R)
KE-KESO- EUTROPHIC
f EUTROPHIC
HE-HYPER EUTROPHIC
1.0
VEAN DEPTH (METERS)
|
10.0
LO
O
o
s
g
PHOSPH
JO I
Zi>C)
li(MQ
EUTROPHIC LAKES
(FLORIDA)
0- OLICOTROPHIC
OM-OLIGO UESOT ROPH 1C
ME-MESO-EUTROPHIC
HE-HYPEft EUTROPHIC
-OLICOTROPHIC LAKES
(VOLLENWEIOER)
1.0
10.0
MEAN DEPTH (METERS)
FIGURE VII-14:
ANNUAL NITROGEN (UPPER) AND PHOSPHORUS (LOWER) LOADING
RATES VERSUS MEAN DEPTH FOR THE FIFTY-FIVE LAKES
-126-
-------
Trophic State and Nutrient Budget Relationships
In another phase of the eutrophication studies, partial nitrogen
and phosphorus budgets were calculated for each of the fifty-five lakes.
Literature values for the relative contributions of nitrogen and phos-
phorus from the various sources were used in the budget calculation.
[For a detailed description of the calculations see Shannon (1970)] .
As a whole hypereutrophic and eutrophic conditions were associated with
high nitrogen and phosphorus loadings. The relationships between mean
depth, lake trophic state and nitrogen or phosphorus loadings are ex-
pressed graphically in Figure VII-14. The approach is identical to that
taken by Vollenweider (1968) and his oligotrophic and eutrophic areas
are labeled and denoted by solid lines. Lake coordinates with respect
to mean depth and nitrogen or phosphorus loading are denoted by the
lake number (Table VII-11) and each lake's trophic state (from TSI
ratings of Table VII-11) is given in parentheses. It appeared that
Vollenweider's critical loading areas were too low and that Florida lakes
were able to assimilate more nitrogen and phosphorus than suggested by
Vollenweider before becoming mesotrophic or eutrophic. Accordingly re-
gions more applicable to Florida lakes were delimited by dashed lines and
labeled.
As methods of evaluating nutrient budgets and determining limiting
nutrients become more concise diagrams such as those in Figure VII-14
should offer an avenue for predicting the trophic state of a lake for a
given nutrient budget.
-127-
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SECTION VIII
ACKNOWLEDGEMENTS
Special thanks go to Mr. Carl Swisher of Melrose on whose property
the research lakes are located. Without the availability of these lakes,
the project field work would have been impossible. The cooperation of
Mr. Swisher will, we feel, shorten the time for the accumulation of
knowledge adequate to cope with the serious problems of rehabilitating
many eutrophic lakes in Florida. Special thanks also go to Colonel
Harold Ashley of Melrose for his untiring efforts on behalf of the pro-
ject. Colonel Ashley, a former member of the State of Florida Game and
Fresh Water Fish Commission is a dedicated conservationist who leaves
no stones unturned in his efforts to see that Florida's natural resources
are not destroyed.
During the progress of this study many agencies and individuals
rendered essential and valuable assistance and advice. Many technical
reports, papers and communications were contributed which provided im-
portant background material for the staff. The following list illus-
trates some of the sources from which cooperation was received.
-129-
-------
FEDERAL AGENCIES
Department of the Interior
Environmental Protection Agency
Office of Water Resources Research
Geological Survey
STATE AGENCIES
Trustees of the Internal Improvement Fund
Game and Fresh Water Fish Commission
Dr. James B. Lackey
Adm. Anthony L. Danis
Dr. John H. Davis
Dr. H. D. Putnam
Dr. P. L. Brezonik
Dr. W. H. Morgan
Dr. E. E. Shannon
Dr. Jackson L. Fox
Mr. Roger Yorton
Mrs. Zena Hodor
Mr. Arley DuBose
Mr. Frank Browne
Mr. Glen Brasington
CONSULTANTS
Melrose, Florida
Melrose, Florida
Gainesville, Florida
PROJECT STAFF MEMBERS
Environmental Engineering
Department
Environmental Engineering
Department
Environmental Engineering
Department
Environmental Engineering
Department
Environmental Engineering
Department
Environmental Engineering
Department
Environmental Engineering
Department
Environmental Engineering
Department
Environmental Engineering
Department
Environmental Engineering
Department
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Mr. Thomas Salmon
Mr. Bill Van Veldhuisen
Mr. Samuel Richardson
Mr. Roger King
Mrs. Jeanne Dorsey
Mrs. Terrie Woodfin
Mrs. Effie Galbraith
Miss Shirley Jordan
Mr. Truman Perry
Dr. Roy Me Ca Id in
Prof. Thomas deS. Furman
Dr. H. K. Brooks
Dr. Paul Maslin
Dr. Karolyn Maslin
Dr. J. H. Davis
OTHERS
Environmental
Department
Environmental
Department
Environmental
Department
Environmental
Department
Environmental
Department
Environmental
Department
Environmental
Department
Environmental
Department
Engineering
Engineering
Engineering
Engineering
Engineering
Engineering
Engineering
Engineering
Melrose, Florida
Environmental Engineering
Department
Environmental Engineering
Department
Geology Department
Chico State College
Chico, California
Chico State College
Chico, California
Botany Department
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SECTION IX
REFERENCES
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examination of water and wastewater, 12th ed. New York.
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. 1948b. Fertilization of lakes -- good or bad? Mich. Conserv.
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Beeton, A. M. 1965. Eutrophication of the St. Lawrence Great Lakes.
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Berg, K. 1958. Investigations on Pure Lake 1950-1954. Limnologlcal
studies on cultural influences. Folia Limnol. Scand. 10, 1-189.
Black, A. P. and Brown, E. 1951. Chemical character of Florida's
waters 1951. State Bd. Conservation, Div. Water Surv. and
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Borecky, G. W. 1956. Population density of the limnetic cladocera of
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Brezonik, P. L. 1968. The dynamics of the nitrogen cycle in natural
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and Lee, G. F. 1968. Denitrification as a nitrogen
sink in Lake Mendota, Wis., Envir, Sci. Technol. 2, 120-25.
and Putnam, H. D. 1968. Eutrophication: Small Florida
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1969. Eutrophication: The process and its potential
for modeling, Proc. Eutrophication Workshop Southeast, St. Petersburg,
Fla., Univ. of Fla. Water Resources Center, Publ. pp 290.
., Morgan, W. H., Shannon, E. E., and Putnam, H. D. 1969.
Eutrophication factors in north central Florida lakes. Water Resources
Research Center. Publ. No. 5, Bull. Series No. 134, Fla. Eng. and Indus.
Exper. Sta. pp 56-66.
Brooks, J. L. and Dodson, S. I. 1965. Predation, body size and composition
of plankton. Science 150: 28-36.
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Brooks, J. L. 1969. Eutrophication and changes in the composition of
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Burgess, J. E. 1964. Summary report of Lake Apopka. Florida State Bd.
of Health, 23 pp. (mimeo).
Clark, W. E., Musgrove, R. H., Menke, C. D. and Cagle, J. W., Jr. 1962.
Interim report on the water resources of Alachua, Bradford, Clay and
Union Counties, Florida. Fla. Geol. Surv., Inf. Arc. No. 36. 92 pp.
, Musgrove, R. H., Menke, C. D., and Cagle, J. W., Jr.
1964. Water resources of Alachua, Bradford, Clay, and Union Counties,
Florida. Fla. Geol. Surv. Rept. of Invest. No. 35, 170 pp.
Collins, D. W. and Howard, C. S. 1927. Chemical character of Florida
waters. U.S. Geol. Surv. Wat. Supp. Paper 596-G, Washington, B.C.
Connell, J. H. 1961. The influence of interspecific competition and
other factors on the distribution of the barnacle Chthamalus stellatus.
Ecology 42: 710-723.
Creitz, G. I. and Richards, F. A. 1955. The estimation and character-
ization of plankton populations by pigment analysis. III. A note on
the use of "Millipore" membrane filters in the estimation of plankton
pigments. Jour. Marine Res. (Sears Foundation) 14, 211-216.
Curl, H. 1959. The origin and distribution of phosphorus in western
Lake Erie. Limnol. Oceanogr. 4, 66-76.
Dodson, S. I. 1970. Complementary feeding niches sustained by size-
selective predation. Limnol. Oceanog. 15: 131-137.
Edmondson, W. T. 1965. Reproductive rate of planktonic rotifers as
related to food and temperature in nature. Ecol. Mang. 35: 61-111.
. 1968. Water quality management and lake eutrophica-
tion: The Lake Washington case. In water resources and public
policy. T. H. Campbell and R. 0. Sylvester (eds). Univ. of Washington
Press, Seattle, pp 139-178.
Einsele, W. 1941. Die Umsetzung von zugefuhrtem, anorganischem Phosphat
im eutrophen See und ihre Ruckwirkungen auf seinen Gesamthaushalt.
Z. Fisch. 39, 407-488.
Elbourne, C.A. 1966. The life cycle of Cyclops strenuus strenuus
Fischer in a small pond. J. Anim. Ecol. 35: 333-347.
Feth, J. H. 1966. Nitrogen compounds in natural waters-a review.
Water Resources Res. 2, 41-58.
Fitzgerald, G. P. 1968. Personal communication. Univ. of Wis.
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Frank, P. W., Boll, C. G., and Kelly, R. W. 1957. Vital statistics of
laboratory cultures of Daphnia pulex DeGeer as related to density.
Physiol. Zool. 30: 287-305.
Fruh, E. G. 1967. The overall picture of eutrophication. Jour. Water
Poll. Contr. Fed. 39, 1449-1463.
Fryer, G. 1968. Evolution and adaptive radiation in the Chydoridae
(Crustacea: Cladocera): a study in comparative functional morphology
and ecology. Phil. Iran. Royal Soc., Series B. 254: 221-385.
Goldman, C. R. 1961. The contribution of alder trees (Alnus tenuifolia)
to the primary productivity of Castle Lake, California. Ecology
42, 282-288.
. 1964. Primary productivity and micronutrient limiting
factors in some North American and New Zealand lakes. Verh. Internat.
Verein. Lunnol. 15, 352-359.
. 1965. Micronutrient limiting factors and their detection
in natural phytoplankton populations, p. 121-135. In C. R. Goldman
(ed) Primary Productivity in Aquatic Environments. Mem. 1st. Ital.
Idrobiol., 18 Suppl., Univ. of Calif. Press, Berkeley.
Hall, D. J. 1964. An experimental approach to the dynamics of a natural
population of Daphnia galeata Mendptae. Ecology 45: 94-112.
Hansen, K. 1962. The dystrophic lake type. Hydrobiologia 19, 183-191.
Harkness, W. J. K. and Pierce, E. L. 1940. The limnology of Lake Mize,
Florida. Quart. J. Florida Acad. Sci. 5, 96-116.
Hasler, A. D. 1957. Natural and artificially (air-ploughing) induced
movement of radioactive phosphorus from the muds of lakes. UNESCO
Int. Conf. Radioisotopes 4, 658-675.
. 1963. Wisconsin-1940-1961. In Limnology in North
America, D. G. Frey (ed) Univ. Wisconsin Press, Madison, pp 55-94.
Hazelwood, D. H. and Parker, R. A. 1961. Population dynamics of some
freshwater zooplankton. Ecology 42: 266-274.
Hooper, F. F. and Ball, R. C. 1964. Responses of a marl lake to
fertilization. Trans. Amer. Fish Soc. 93, 164-173.
, Ball, R. C. and Tanner, H. A. 1952. An experiment in the
artificial circulation of a small michigan lake. Trans. Amer.
Fish Soc. 82, 222-241.
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Hubbs, C. L. 1921. An ecological study of the life history of the
freshwater artherine fish Labidesthes sicculus. Ecology 2: 262-276.
Huffstutler, K. K., Burgess, J. E. and Glenn, B. B. 1965. Biological,
physical, and chemical study of Lake Apopka, 1962-1964. Florida
State Board of Health, 78 pp (mimeo).
Hutchinson, G. E. 1957. Treatise on limnology. Vol. I. Wiley, New York.
pp 1015.
. 1967. Treatise on limnology, Vol II. Wiley, New
York, pp 1115.
Ilkowska, A. H., Gliwicz, Z., and Spodniewska, I. 1966. Zooplankton
production and some trophic dependences in the pelagic zone of two
Massurian lakes. Verh. int. Verein. Theor. angew. Limnol. 16: 432-440.
Ingle, L., Wood, T. R. and Banta, A. M. 1937. A study of longevity,
reproduction, and heart rate in Daphnia longispina as influenced by
limitation in quantity of food. J. Exper. Zool. 76: 324-352.
Ivlev, V. S. 1961. Experimental ecology of the feeding of fishes.
Yale Univ. Press, New Haven, Connecticut. 302 pp.
Karcher, F. H. 1939. Untersuchungen uber den Stickstoffhaushalt in
ostpreussischen Waldseen. Arch. Hydrobiol. 35, 177-266.
Kenner, W. E. 1964. Maps showing depths of selected lakes in Florida.
Fla. Geol. Surv. Inf. Circ. 40, 82 pp.
Kerr, P. C., Paris, D. F. and Brockway, D. L. 1970. The interrelation
of carbon and phosphorus in regulating heterotrophic and autotrophic
populations in an aquatic ecosystem. Proc. 25th Industrial Waste
Conf., Purdue Univ. (in press).
Lackey, J. B. 1945. Plankton productivity of certain southeastern
Wisconsin lakes as related to fertilization. II. Productivity,
Sewage Wks. J. 17, 795-802.
Lackey, J. B. and Lackey, E. W. 1967." A partial checklist of Florida
freshwater algae and protozoa with reference to McCloud and Cue Lakes.
Water Resources Research Center Publ. No. 3, Bull. Series No. 131,
Fla. Eng. and Indus. Exper. Sta.
Langford, R. R. 1950. Fertilization of lakes in Algonquin Park,
Ontario. Trans. Amer. Fish Soc. 78, 133-144.
Lee, G. F. and Fruh, E. G. 1966. The aging of lakes. Indust. Water
Engin. 3 (2), 26-30.
-136-
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McAllister, C. D. 1969. Aspects of estimating zooplankton production
from phytoplankton production. J. Fish Res. Bd. Can. 26: 199-220.
McGauhey, P. H., Eliassen, R., Rohlich, G. A., Ludwig, H. F., and
Pearson, E. A. 1963. Comprehensive study on the protection of water
resources of Lake Tahoe basin through controlled waste disposal.
Prepared for the Board of Directors, Lake Tahoe Area Council, Al
Tahoe, Calif, pp 157.
McLane, W. M. 1955. The fishes of the St. Johns River System. Ph.D.
dissertation. University of Fla., Gainesville, Fla. pp 376.
Mendenhall, W. 1967. Introduction to probability and statistics.
2nd Ed. Wadsworth Publishing Co., Inc. Belmont, Calif. 393 pp.
Morrison, D. F. 1967. Multivariate statistical methods. McGraw Hill
Book Co., New York, pp 338.
Mortimer, C. H. 1939. The work of the Freshwater Biological Association
of Great Britain in regard to water supplies. The nitrogen balance of
large bodies of water. Offie. Circ. British Waterworks Assoc. 21,
1-10.
Nelson, P. R. and Edmondson, W. T. 1955. Limnological effects of fer-
tilizing Bare Lake, Alaska. Fishery Bull. Fish Wildl. Serv. U.S.
102, 414-436.
Nordlie, F. G. 1967. Chemical and biological dynamics in two solution
lakes. Final Rept. to Fed. Wat. Poll. Contr. Admin. Grant No.
WP-00530 (Mimeo).
Odum, H. T. 1953. Dissolved phosphorus in Florida waters, Fla. Geol.
Surv. Rept. Invest. 9, 1-40.
Paine, R. T. 1966. Food web complexity and species diversity. Amer.
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Pearsall, W. H. 1922. A suggestion as to factors influencing the dis-
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Ricker, W. E. 1958. Handbook of computations for biological statistics
of fish populations. Roger Dunamel, F.R.S.C. Ottawa, Canada.
Rohlich, G. A. and Lea, W. L. 1949. The origin and quantities of plant
nutrients in Lake Mendota. Report Univ. Wisconsin Lake Investigation
Committee, Madison, Wis. (mimeo, 8 pp).
-137-
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Sawyer, C. N., Lackey, J. B. and Lenz, A. T. 1945. Investigation of
the odor nuisances in the Madison Lakes, particularly Lakes Monona,
Waubesa, and Kegonsa from July, 1943 to July, 1944. Report to
Governor's Committee, Madison, Wis. 92 pp.
Schneider, R. F. and Little, J. A, 1968. Characterization of bottom
sediments and selected nitrogen and phosphorus sources in Lake Apopka,
Florida. U.S. Dept. of Interior, Fed. Wat. Poll. Contr. Admin.,
Southeast Water Lab. Tech. Rept. (mimeo).
Shannon, E. E. 1970. Eutrophication-trophic state relationships in
north and central Florida lakes. Dissertation presented to the
Graduate Council of the University of Florida.
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Ecol. Monogr. 24: 69-88.
1961. Growth and regulation of animal populations.
Holt, Rinehart and Winston, Inc., New York.
. 1968. How to be a predator. Am Zoologist 8: 43-51.
Sokal, R. R. and Sneath, P. H. 1963. Principles of numerical taxonomy,
W. H. Freeman, San Francisco and London.
Stewart, K. M. and Rohlich, G. A. 1967. Eutrophication-a review.
Calif. State Water Qual. Control Bd., Publ. No. 34, 188 pp.
Straskraba, M. 1963. Share of the littoral region in the productivity
of two fishponds in Southern Bohemia. Rospravy CSAV, rada MPV,
73, 13: 63 pp.
Stross, R. G., Neess, J. C. and Hasler, A. D. 1961. Turnover time and
production of planktonic Crustacea in limed and reference portion of
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Control Administration. Analytical techniques for the national eu-
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Vollenweider, R. A. 1968. Scientific fundamentals of the eutrophication
of lakes and flowing waters, with particular reference to nitrogen
and phosphorus as factors in eutrophication, O.C.E.D. Report, DAS/CSI
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-138-
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Werner, R. G. 1969. Ecology of limnetic bluegill (Lepomis macrochirus)
fry in Crane Lake, Indiana. Amer. Nat. 81: 164-181.
Wetzel, R. G. 1962. A comparative study of the primary productivity of
higher aquatic plants, periphyton, and phytoplankton in a saline lake.
Ph.D. Dissertation, Univ. of Calif. Davis, pp 156.
Whiteside, M. C. 1970. Danish chydorid cladocera: modern ecology and
core studies. Ecol. Monog. 40: 79-118.
and Harmsworth, R. V. 1967. Species diversity in
chydorid (Cladocera) communities. Ecology 48: 664-667.
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SECTION X.
PUBLICATIONS
Shannon, E. E. 1970. Eutrophication-trophic state relationships in
north and central Florida lakes. Dissertation presented to the
Graduate Council of the University of Florida.
Maslin, P. E. 1969. Population dynamics and productivity of zooplankton
in two sandhills lakes. A dissertation presented to the Graduate
Council of the University of Florida
Maslin, K. R. 1970. The interactions of littoral zooplankton and their
fish predators. A dissertation presented to the Graduate Council of
the University of Florida.
Lackey, J. B. and Lackey, E. W. 1967. A partial checklist of Florida
fresh-water algae and protozoa with reference to McCloud and Cue
Lakes. Water Resources Research Center. Publ. No. 3, Bull. Series
No. 131, Fla. Eng. and Indus. Exper. Sta.
Putnam, H. D., Shannon, E. E., and Brezonik, P. L. 1970. Lake eutro-
phication: a critical look at the problem. Presented at the
International Symposium on Hydrogeochemistry and Bio-chemistry.
Tokyo, Japan.
Brezonik, P. L., Morgan, W. H., Shannon, E. E., and Putnam, H. D. 1969.
Eutrophication factors in north central Florida lakes. Water Re-
sources Research Center. Publ. No. 5, Bull. Series No. 134, Fla. Eng.
and Indus. Exper. Sta. pp 101.
Brezonik, P. L. 1968. Application of mathematical models to the
eutrophication process. Proc. llth Conf. Great Lakes Reg. 16-30.
Internat. Assoc. Great Lakes Res.
Brezonik, P. L. and Putnam, H. D. 1968. Eutrophication: small Florida
lakes as models to study the process. Proc. 17th Southern Water Res.
and Poll. Control Conf.
Brezonik, P. L. 1970. Limnological features of north central Florida
lakes. Presented at the 33rd Annual meeting of the Amer. Soc. of
Limn, and Ocean. Kingston, R. I.
Brezonik, P. L. and Shannon, E. E. 1971. Eutrophication: cause-effect
relationships in Florida lakes, submitted to the Jour, of Sanit. Eng.
Di.v., Amer. Soc. of Civil Eng.
US. GOVERNMENT PRINTING OFFICE: H7J-4M-4B3/M
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SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
I, Report No.
3. Accession No.
w
4. Title
Eutrophication Factors In North Central Florida Lakes
7. Author(s) putnam> H. D., Morgan, W. H., Brezonik, P. L.,
Shannon, E. E., Maslin, P. E.
9. Organization
orIda University
Environmental Engineering Department
Gainesville, Florida
5. Report Date
6. . .
*$,' Performing Organization
Report No. ,
W. Project No.
16010 DON
12. Sponsoring Organization
IS. Supplementary Notes
11. Contract! Grant No.
'W. Type of Report and ,'
Period Covered
16. Abstract A. small Florida lake has been receiving a regimen of nutrient addition
equivalent to 500 mg/m^-yr N and 43 mg/m3-yr P since 1967. Data has been accumulated
through 1969. The effect on the lacustrine ecosystem of various biogenes includes
production by primary producers, species diversity of plankton and certain production
estimates at the secondary trophic level using natural populations of planktivorous
fish. Plankton production using isotopic carbon is ca. 58 grms/m^-yr. Species diver-
sity is slowly changing to a mixed chlorophycean and yellow-green. Biomass of benthic
green filamentous types has increased slightly. Nutrient addition has had little in-
fluence on zooplankton production.
Related studies on 53 other regional lakes have been done using a multi-
dimensional hybrid concept as defined by several trophic state indicators. This
trophic state index has provided a means for ranking the lakes on an arbitrary scale.
Cluster analysis utilizing pertinent characteristics resulted in classification of
other lakes.
Land use patterns and population characteristics were determined photogra-
phically and N and P budgets estimated. Using multiple regression and canonical
analysis, several significant relationships were found between lake trophic state, lake
basin, land,use, and population characteristics,. In general, trophic, state of lakes can
Be expressed go a oimplc relationonip Incorporating N ana P influn rotoc.
17a. Descriptors
*Eutrophication, *Limnology, *Mathematical Model, *Essential Nutrients,
*Primary Productivity, Water Quality, Trophic Level, Aquatic Algae, Fish
Populations
17b. Identifiers
Anderson-Cue Lake
Melrose, Florida
17c. CO WRR Field & Group 05B.05C
18. Availability
Abstractor Z, K. Hodor
Send To:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 20240
institution Univers ity of Florida
WRSIC 102 (REV. JUNE 1971)
GPO 913.281
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