Ecological Research Series
ALGAL NUTRIENT AVAILABILITY AND
LIMITATION IN LAKE ONTARIO DURING IFYGL
Part III
Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Duluth, Minnesota 55804
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7 Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies to deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/3-77-046a
May 1977
ALGAL NUTRIENT AVAILABILITY AND LIMITATION
«
IN LAKE ONTARIO DURING IFYGL
Part III. Algal Nutrient Limitation in
Lake Ontario During IFYGL
by
Nagalaxmi Sridharan
University of Wisconsin
Madison, Wisconsin 53706
and
G. Fred Lee
University of Texas at Dallas
Richardson, Texas 75080
Contract No. R-800537-02
Project Officer
Nelson Thomas
Large Lakes Research Station
Environmental Research Laboratory-Duluth
Grosse lie, Michigan 48138
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
DULUTH, MINNESOTA 55804
-------
DISCLAIMER
This report has been reviewed by the Environmental Research
Laboratory-Duluth, U.S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents necessarily
reflect the views and policies of the U.S. Environmental Protection
Agency, nor does mention of trade names or commercial products consti-
tute endorsement or recommendation for use.
ii
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FOREWORD
Our nation's freshwaters are vital for all animals and plants,
yet our diverse uses of water—for recreation, food, energy,
transportation, and industry—physically and chemically alter lakes,
rivers, and streams. Such alterations threaten terrestrial organisms,
as well as those living in water. The Environmental Research Laboratory
in Duluth, Minnesota develops methods, conducts laboratory and field
studies, and extrapolates research findings
--to determine how physical and chemical pollution affects
aquatic life
--to assess the effects of ecosystems on pollutants
--to predict effects of pollutants on large lakes through
use of models
--to measure bioaccumulation of pollutants in aquatic
organisms that are consumed by other animals, including
man
This report describes the potential significance of algal
nutrients in limiting algal growtn in Lake Ontario and its major
tributaries.
Donald I. Mount, Ph.D.
Director
Environmental Research Laboratory
Duluth, Minnesota
1X1
-------
PREFACE
This project was conducted as part of the International Field Year
for Great Lakes Research and consisted of three separate parts, all di-
rected toward providing information needed to assess the factors limiting
algal growth in Lake Ontario and the amounts of nitrogen and phosphorus in
tributary drainage which would likely become available in the lake. Part I
is concerned with a comprehensive study of the amounts of phosphorus enter-
ing Lake Ontario from U.S. tributaries which will likely become available
in the lake. Particular attention is given to the particulate and organic
forms of phosphorus in the major U.S. tributaries to the lake. Part II is
concerned with a study of the amounts of available nitrogen entering Lake
Ontario from the U.S. tributaries. Part III is concerned with the factors
limiting algal growth in Lake Ontario and in the major U.S. tributaries.
This report presents Part III of this study. Parts I and II are published
as separate reports by the U.S. Environmental Protection Agency under the
title, Algal Nutrient Availability and Limitation in Lake Ontario During IFYGL,
with the following subtitles:
Part I: Available Phosphorus in Urban Runoff and Lake Ontario
Tributary Waters
Part II: Nitrogen Available in Lake Ontario Tributary Water Samples
and Urban Runoff from Madison, Wisconsin
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ABSTRACT
This study was conducted on the potential significance
of nitrogen, phosphorus and micronutrients in limiting
planktonic algal growth in Lake Ontario and its major
tributaries. Standard algal assay procedures were used.
Samples of the open waters of Lake Ontario and Niagara River
waters collected during the spring showed phosphorus limi-
tation. By late summer these waters showed both nitrogen
and phosphorus limitation, Genesee and Oswego Rivers
showed, in general, nitrogen limitation. Samples of the
Black River waters showed both nitrogen and phosphorus
limitation.
This report was submitted in fulfillment of Contract
No. R-800537-02 under the sponsorship of the Environmental
Protection Agency. Work was completed as of June, 1975.
v
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CONTENTS
Foreword „ ill
Preface iv
Abstract v
List of Figures viii
List of Tables x
Acknowledgments xi
I Introduction 1
II Conclusions 6
III Recommendations 7
IV Experimental Procedures 8
V Experimental Results and Discussion .... 19
References <. 44
Appendices
A Algal Bioassays for Lake Ontario Water 45
B Algal Bioassays for Niagara River Waters 45
C Algal Bioassays for Genesee River Waters 45
D Algal Bioassays for Oswego River Waters 45
E Algal Bioassays for Black River Waters 45
vii
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LIST OF FIGURES
No. Page
1 Lake Ontario and Tributary Sampling Sites 5
2 Relationship Between Absorbance and Dry
Weight of Selenastrum capricornutum Cells 13
3 The Growth of Selenastrum. in Genesee River 15
Waters, Sample 14, July 20, 1972
4 The Growth of Selenastrum in Genesee River 16
Waters, Sample 51, May 28, 1973
5 The Growth of Selenastrum in Lake Ontario, 20
Station 45, March 5, 1973
6 The Growth of Selenastrum in Lake Ontario 23
Water, Station 75, July 19, 1972
7 The Growth of Selenastrum in Lake Ontario 24
Water, Sample 19, August 2, 1972
8 The Growth of Selenastrum in Lake Ontario 25
Water, Sample 17, August 2, 1972
9 Effect of Nutrient Spiking on the Growth 26
of "Natural" Lake Ontario Algae in Lake
Ontario Water, Station 64, August 23, 1972
10 The Growth of Selenastrum in Niagara River 31
Water, Sample 57, June 15, 1973
11 The Growth of Selenastrum in Niagara River 32
Water, Sample 41, April 30, 1973
12 The Growth of Selenastrum in Niagara River 33
Water, Sample 50, May 27, 1973
13 The Growth of Selenastrum in Genesee River 35
Water, Sample 42, April 30, 1973
14 The Growth of Selenastrum in Oswego River 37
Water, Sample 28, March 2, 1973
viii
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FIGURES (continued)
No. Page
15 The Growth of Selenastrum in Oswego River 38
Water, Sample 55, June 4, 1973
16 The Growth of Selenastrum in Oswego River 39
Water, Sample 30, March 20, 1973
17 The Growth of Selenastrum in Black River 41
Water, Sample 53, May 28, 1973
IX
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LIST OF TABLES
No. Page
1 Sampling Dates and Initial Phosphorus and 2
Nitrogen Concentrations for Lake Ontario
and Tributary Water
2 Synthetic Algal Nutrient Medium, NAAM 10
3 Algal Bioassay Experimental Design 12
4- Response of Incubated Treated Samples 28
Relative to Incubated Lake Water Samples
5 Effect of Alum Treatment on the Growth of 30
"Natural" Lake Algae in Lake Ontario Water
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ACKNOWLEDGMENTS
This investigation was conducted primarily at the
University of Wisconsin, Madison. In addition to support
given for this investigation by the U.S. Environmental
Protection Agency, support was given by the Department
of Civil and Environmental Engineering at the University
of Wisconsin, Madison, and the Institute for Environmental
Sciences at the University of Texas at Dallas. This
investigation was conducted as part of the International
Field Year for the Great Lakes.
Special recognition should be given to the assis-
tance of personnel from the Grosse lie laboratory of the
U.S. EPA, especially N. Thomas and T, Davies; also, the
advice and assistance of G.P. Fitzgerald is greatly
appreciated.
XI
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SECTION I
INTRODUCTION
The objective of this study was to determine the
limiting nutrients for the algal growth in Lake Ontario.
The study included the measurement of the growth response
of laboratory grown and natural algae in nutrient spiked
Lake Ontario water.
During the summer and fall of 1972 and spring, 1973,
water samples were collected from open lake at five
locations and from the mouths of the Niagara, Genesee,
Oswego and Black Rivers.
One or two gallon water samples from the surface
of Lake Ontario were collected in pre-washed polyethy-
lene containers and transported to Madison, Wisconsin,
via commercial airliner or by car, depending upon when
the samples were collected. The day of arrival at
Madison ranged from three days to two weeks after col-
lection, depending upon the mode of transportation.
Upon arrival, the water samples were stored at 4 C.
Figure 1 identifies the sampling stations in the open
lake and its tributaries. Table 1 presents the samp-
ling dates and the initial phosphorus and nitrogen
concentrations of the samples collected.
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Table 1. SAMPLING DATES AND INITIAL PHOSPHORUS AND NITROGEN
CONCENTRATIONS FOR LAKE ONTARIO AND TRIBUTARY WATER
Location
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Lake
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Ontario
Station/
Sample No.
10
10
10
10
10
93
64
75
75
75
75
75
45
45
45
45
19
Near Niagara River
7
Near Niagara River
9
Near Rochester NY
17
Near Rochester NY
20
Date
26
5
1
2
15
24
23
19
5
1
2
15
5
1
2
15
2
23
19
2
14
Collected
June
Mar 7
Apr
May
Jun
Aug
Aug
Jul
Mar
Apr
May
Jun
Mar
Apr
May
Jun
Aug
Jul
Jul
Aug
Aug
7
7
7
7
7
7
7
7
3
3
3
7
7
7
7
3
3
3
7
3
3
3
72
3
2
2
2
3
73
7
2
72
7
2
72
7
2
TP
mg/1 P
18
+ 3
5
+ 19
9
15
17
36
+ 3
3
13
10
+ 6
4
14
10
25
14
100
43
37
"TN
mg/1 N
*o
0
*o
*o
0
0
0
*o
0
0
0
*o
*o
*o
.07
—
.31
.05
--
—
.05
.39
.35
.28
.05
.40
.35
.27
.05
—
.05
.10
—
—
Ccontinued)
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Table 1. SAMPLING DATES AND INITIAL PHOSPHORUS AND NITROGEN
CONCENTRATIONS FOR LAKE ONTARIO AND TRIBUTARY WATER
Location
Oswego River
Oswego River
Oswego River
Oswego River
Oswego River
Oswego River
Oswego River
Oswego River
Oswego River
Oswego River
Oswego River
Black River
Black River
Black River
Black River
Black River
Black River
Fort Niagara
Niagara River
Niagara River
Niagara River
Niagara River
Niagara River
Niagara River
Niagara River
Station/
Sample No.
30
31
35
43
52
54
55
59
11
28
29
12
25
36
44
53
60
6
18
27
33
41
50
56
Date Collected
20 Mar 73
28 Mar 73
29 Mar 73
1 May 73
28 May 73
31 May 73
4 Jun 73
17 Jun 73
18 Jul 72
2 Mar 73
12 Mar 73
19 Jul 72
28 Aug 72
29 Mar 73
1 May 73
28 May 73
17 Jun 73
10 Jul 72
2 Aug 72
26 Feb 73
28 Mar 73
30 Apr 73
27 May 73
15 Jun 73
TP
mg/1 P
306
95
105
96
104
87
96
147
—
80
106
_ —
53
34
34
41
99
8
22
18
34
22
26
59
"TN
mg/1 N
_ _
1.27
1.16
1.42
1.49
—
—
2.30
—
1.34
—
—
—
0.59
0.75
0.25
* 0 . 0 5
--
--
--
0.45
0.82
1.13
(continued)
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Table 1. SAMPLING DATES AND INITIAL PHOSPHORUS AND NITROGEN
CONCENTRATIONS FOR LAKE ONTARIO AND TRIBUTARY WATER
Location
Station/
Sample No.
Date Collected
TP
mg/1 P
"TN
mg/1 N
Beaver Island
Niagara
Niagara
Niagara
Niagara
Genesee
Genesee
Genesee
Genesee
Genesee
Genesee
River
River
River
River
River
River
River
River
River
River
32
40
49
57
14
16
34
42
51
58
28
30
27
15
20
2
29
30
28
16
Mar
Apr
May
Jun
Jul
Aug
Mar
Apr
May
Jun
7
7
7
7
3
3
3
3
30
15
51
86
72
7
7
7
7
7
2
3
3
3
3
167
386
105
173
204
-
-
-
-
0.
-
2.
1.
1.
2.
-
-
-
-
69
-
21
52
26
26
"TN = NOQ -N + total Kjeldahl-N; + = Dissolved reactive phosphorus only;
o
* = NQ~-N only
Phosphorus and nitrogen values were analyzed by William Cowen, University of
Wisconsin, Madison.
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NIAGARA
FALLS
BEAVER ISLAND
Figure I. Lake Ontario and tributary sampling sites
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SECTION II
CONCLUSIONS
It is concluded for Lake Ontario waters and the
Niagara and Black Rivers that phosphorus is the key
limiting element controlling excessive algal growth.
At certain times of the year, especially in late summer,
nitrogen also limits algal growth in these waters. The
Genesee River water samples showed nitrogen to be the
element most likely controlling algal growth. Similar
results showing nitrogen controlling growth were
obtained for the Oswego River; however, some Oswego
River samples showed algal growth limitation possibly
due to a lack of micronutrients or more probably, the
presence of a toxic metal whose toxicity is eliminated
by the addition of EDTA.
The overall conclusion derived from this study is
that steps should immediately be taken to reduce the
phosphorus input to Lake Ontario to the maximum extent
economically feasible which includes treatment of all
domestic wastewaters entering Lake Ontario or its trib-
utaries for 90 percent phosphorus removal.
-------
SECTION III
RECOMMENDATIONS
Based on the results of this study, it is recom-
mended that all municipalities of more than 1,000 people
which contrubute domestic wastewaters to Lake Ontario
and its tributaries immediately initiate 90 percent
phosphorus removal from its domestic wastewaters.
The following additional studies are recommended:
1. One of the major water quality problems of
Lake Ontario is the excessive attached algal
growth near the shore caused primarily by
Cladophora. It is recommended that studies be
made on the factors limiting Cladophora growth
on the near shore waters of Lake Ontario.
2. Additional studies of the factors limiting algal
growth in the Genesee and Oswego Rivers should
be initiated with particular attention given to
determining whether phosphorus input reduction
to these waters can be of sufficient magnitude
to make algal growth limited by phosphorus within
the rivers and river mouths. Also, attention
should be given to the possible presence of
toxicants in these rivers which is currently
limiting algal growth.
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SECTION IV
EXPERIMENTAL PROCEDURES
REAGENTS
A stock phosphate solution was prepared by dis-
solving KtUPO^ in glass-distilled water. Nitrogen added
to the Lake Ontario cultures was in the form of nitrate.
A stock nitrate solution was prepared by dissolving NaNO,.
in glass-distilled water.
The stock micronutrient solution (EPA 1971) con-
tained 185.52 mg/1 H3B03, 265.26 mg/1 MnCl2, 32.709 mg/1
ZnCl2, 0.780 mg/1 CoCl2, 0.009 mg/1 CuCl2, 7.26 mg/1
Na2MoOl4'2H20, 96.0 mg/1 FeClg, and 300 mg/1 Na2EDTA- 2H20.
For the experiments where -^C-technique was used,
carbon-14 was added to the samples as a basic carbonate
14
solution. Sealed ampules of C-bicarbonate were pur-
chased and diluted to the appropriate volume to produce
14
1 yCi C/ml solution. Sodium hydroxide solution was
14
added to the C-bicarbonate solution to raise the pH to
10.4 to prevent losses of 14C-C02.
The scintillation cocktail used in the counting pro-
cedure contained 75.0 g napthalene, 10.5 g 2,5-diphenyl
oxazole (PPO) and 0.45 g l,4-bis-{2-C4-methyl-5-phenyl-
oxazolyl) - benzene (dimethyl PoPoP) diluted to 1 liter
with 300 ml ethylene glycol monoethyl ether (cellusolve)
and 1,4-dioxane. All reagents used in the preparation
of this cocktail were scintillation grade.
-------
Sample Activity was determined by liquid scin-
tillation counting using a Packard 3320 Tri-Carb Scin-
tillation Spectrometer. All samples were counted for
10 minutes and the activity of each sample was reported
in counts per minute (CPM) after correcting the observed
data for counting time and quenching.
ASSAY METHODS
Filtered Lake Water
In filtered lake and tributary waters, the Algal
Assay Procedure (AAP) (National Eutrophication Research
Program, 1971) was used and the growth response of a
laboratory algal culture Selenastrum capricornutum was
studied using absorbance (light scattering) measurements.
One liter of the sample was autoclaved at 15 psi for
15 minutes, cooled to room temperature, and let stand
for a few hours. The sample was then filtered through
0.45y pore size membrane filter. The ph of the test
water was then measured. If the pH of the filtered sample
was not between 7.0 and 8.5, an adjustment of pH was made
by passing air or C02 through the sample. The bioassays
were run on 40 ml volumes of the autoclaved filtered samples
in 125 ml flasks. The preparation of the glasswares followed
the recommended procedure in "Algal Assay Procedure, Bottle
Test," (National Eutrophication Research Program, 1971).
Selenastrum capricornuturn was the test algae grown in a
synthetic algal nutrient medium (Table 2) with 3X
phosphorus and 3X nitrogen. One-to-two-weeks1 old
culture was used as a source of inoculum. The cells
from the Selenastrum culture were centrifuged for 30
minutes at 1500 rpm and the supernatant was discarded.
The sedimented cells were resuspended in sodium bicarbo-
nate solution (15 mg NaHCO^/l) and centrifuged again for
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Table 2. SYNTHETIC ALGAL NUTRIENT MEDIUM, NAAM
Compound
NaN03
MgCl2
MgS04-7H20
CaCl2'2H20
NaHCOQ
o
H3B03
MnCl2
ZnCl2
CoCl2
CuCl2
Na2Mo04-2H20
FeCl3
Na0EDTA-2H00
Concentration
(mg/1)
25. 50
1.04
5.70
14.70
4.41
15.00
185. 52
264.26
32.7
0.78
0.009
7.26
96.00
300.00
Element
N
P
Mg
S
C
Ca
Na
K
B
Mn
Zn
Co
Cu
Mo
Fe
Concentration
(mg/1)
4.20
0.186
2.90
1.91
2.14
1.20
11.00
0.47
32.46
115.37
15.69
0.35
0.004
2.88
33.05
10
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30 minutes at 1500 rpm. The sedimented algal cells were
resuspended in the bicarbonate solution and the number of
cells in suspension was counted using a hemocytometer-
The suspension was then diluted with bicarbonate solution
to give the final cell concentration of 2 x 10 cells/ml.
3
An initial cell concentration of 10 cells/ml of the sample
was used.
The water samples were spiked with phosphorus, nitrogen
or micronutrients to give the final concentration of
100 yg P/l, 1000 yg N/l, and the concentration equivalent
of AAP micronutrients, respectively. The flasks with water
samples were spiked with phosphate, nitrate, and micro-
nutrients, individually and in combination, to identify the
growth-limiting nutrient(s). Table 3 is an outline of
the procedure which was employed to assess the nutrient
status of Lake Ontario water. The flasks with the test
samples were incubated at 24 + 3 C under "cool-white"
fluorescent lighting - 400 ft c ±10 percent illumination.
Measurement of in vivo absorbance was made on days 8 to 16
of the incubation, using 10 cm cells and Beckman DU Spectro-
photometer. Aliquots taken for absorbance measurements
were returned to their flasks after taking the reading.
The absorbance reading at 750 nm for an algal culture
was calibrated with the dry weight of algae. A known ali-
quot of a dense culture of Selenastrum capricornutum was
filtered through a glass fiber filter, oven-dried at 110 C,
cooled, and weighed. The same culture was diluted by dif-
ferent volumes of water and the absorbance measured for
each dilution. A calibration curve is presented in
Figure 2,
To be sure that the absorbance measurements were sen-
sitive enough for the purpose of the present study, fluo-
rescence measurements were made on some of the AAP tests
and the results were compared with the results from the
11
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Table 3. ALGAL BIOASSAY.EXPERIMENTAL DESIGN
Treatment
No. Flasks
Lake water control - 40 ml lake Water
Phosphorus spikes - Lake water + 100 yg P/l
Nitrogen spikes - Lake water + 1000 yg N/l
Combined spikes - Lake water + 100 yg P/l
+ 1000 yg N/l
Micronutrient spikes - Lake water + micro-
nutrients
Combined Micronutrient spikes - Lake water +
Micronutrients + 1000 yg N/l
Growth References - Phosphorus
*NAAM-P medium
NAAM-P + 100 yg P/l
Growth References - Nitrogen
-NAAM-N medium
NAAM-N + 1000 yg N/l
TOTAL
3
3
3
3
30
'synthetic algal assay medium (Table 2)
12
-------
0.5
L±J
O
E 0.4
o
O
0.3
O
in
< 0.2
LU
o
CD 0-1
a:
a
CD
0
0
10 20 30
DRY WEIGHT OF SELENASTRUM CELLS mg/l
40
Figure 2. Relationship between absorbance and dry weight of Selenastrum
capricornutum cells.
-------
absorbance measurements. Fluorescence can be measured at
early stages of growth increases, due to the sensitivity
of the technique. Figure 3 is a plot of fluorescence vs
time for Sample 14- of Genesee River water sampled on July
20, 1972. The measurements of increase in fluorescence were
made from days 3 through 10. The results indicate an in-
creased growth response of Selenastrum in samples with the
addition of nitrogen plus micronutrients. This is similar
to the curve presented in Figure 35 which is a plot of
absorbance vs time for Genesse River water sample. The ab-
sorbance measurements were made from days 9 through 13 and
the results as seen from the Figure 4. indicate an in-
creased growth with nitrogen plus micronutrients addition
in the sample. Since both absorbance and fluoresence mea-
surements served the same purpose in the present study, due
to the easy accessibility of the instrument, absorbance mea-
surements were used in the present study to follow the
growth response of Selenastrum.
Unfiltered Lake Water
14
In the present nutrient spiking study, C-technique
was used to assess the growth of the "natural" algae pre-
sent in unfiltered lake water. The first step in processing
the unfiltered samples was to determine the initial produc-
tivity of the sample. Six 25 ml aliquots of the sample were
14 =
spiked with 0.5 yd C~C03 each and incubated for four hours.
Three of the replicates were incubated under 400 ft c of
light supplied by fluorescent lights. The remaining fhree
samples were incubated at the same temperature as the first
three samples but in the dark. After a four-hour incubation
period, the samples were filtered through 0*4-5 y pore size
Millipore filters at a pressure differential equivalent to
15 cm of mercury. During the filtration step, the sample
14
-------
3000
2500
X
O 2000
ro
UJ
o
z
UJ
o
en
u
a:
o
ID
1500
1000
500
I
I
GENESEE RIVER SAMPLE 14
JULY 20, 1972
O RIVER WATER (RW)
RW + P
RW + N
RW + P + N
RW + micro
R W + N + micro
2468
TIME,days
Figure 3. The growth of Selenastrum in Genesee River waters.
10
-------
LjJ
O
QQ
IT
O
(S)
CD
0.8
0.7 -
0.6 -
0.5 -
I I I I
GENESEE RIVER SAMPLE 51
MAY 28, 1973
O RIVER WATER (RW)
RW + P
RW + N
RW + P + N
RW + N + micro
RW + P + N + micro
6 8
TIME,days
Figure 4. The growth of Selenastrum in Genesee River water.
16
-------
bottles were rinsed twice with distilled water and the fil-
ters were rinsed five times with distilled water. The total
wash volume was approximately 50 ml.
Filters were placed in a desiccator containing concen-
trated HC1 for one-half hour and then dried overnight in a
second desiccator containing silica gel. The filters were
dissolved in a 10 ml scintillation cocktail and 5 ml dioxane.
The samples were counted for ten minutes to determine the
amount of carbon-14 incorporation. Net carbon fixation for
the sample was calculated by subtracting the dark bottle
fixation from the light bottle fixation.
Once the initial productivity of the sample was deter-
mined, the experiment was continued to determine the effect
of nutrient additions. Fifty ml aliquots of the lake water
samples were placed in 125 ml culture flasks. The phosphate,
nitrate, and micronutrient solutions were then added singu-
larly and in combination to the lake water sample. Tripli-
cate samples were prepared for each experimental condition.
The flasks were then sealed with parafilm wax paper and
incubated for one week at 22 +_2°C under 400 ft c of light.
A set of screw-capped, four-oz jars was prepared for
dark incubation by painting the glass walls completely black.
A set of unpainted four-oz jars was used for the incubation
of the samples in light.
Following the incubation period of one week, two 25
ml samples were taken from each of the triplicate flasks.
One sample was placed in a four-oz jar painted black for
dark incubation and the other sample was placed in the un-
14 =
painted jar. To each of the jars, one-half uCi C-C03 was
added, and the jars were incubated for an additional four-
hour period.
The short four-hour incubation period was completed
under the same conditions of temperature and light intensity
17
-------
as the longer one-week incubation period except for keep-
ing the designated dark bottle samples out of the light.
The samples were filtered and the filters were processed as
described earlier. The net carbon assimilation was calcula-
ted as the difference between the light and dark bottle
fixation and compared to the initial and incubated lake
water samples.
18
-------
SECTION V
EXPERIMENTAL RESULTS AND DISCUSSION
RESULTS
The results of the algal bioassay on Lake Ontario and
its tributary waters will be dealt with individually in this
section.
Lake Ontario
The bioassay response of Selenastrum capricornutum,
with and without the addition of nutrients, was measured
using absorbance. Five samples from Station 10, situated
north of Welland Canal, four samples from Station 45 located
north of Sodius Bay and one sample each from Stations 64 and
93 were received and used in the algal bioassay studies. In
addition, two samples from near the mouth of Niagara River,
two samples from near the mouth of Genesee River and one
sample from near Toronto, Ontario, were collected and AAP
tests were run. The data are tabulated in Appendix A.
The water samples had total phosphorus concentrations
in the range of 5 to 43 yg P/l and the total nitrogen 0.25
to 0.40 mg N/l. All 21 samples collected from Lake Ontario
showed phosphorus or phosphorus and nitrogen limitation.
Typical growth response curves are presented in Figure 5.
These figures are a plot of absorbance vs time for
Lake Ontario water sample collected from Station 45 on
March 5, 1973. The vertical lines indicate the absorbance
range obtained for triplicate samples. An increase in algal
19
-------
M
O
I I
LAKE ONTARIO STATION 45
MARCH 5, 1973
o LAKE WATER (LW)
D LW + P
A LW + N
O LW + P + N
LW + N + micro
LW + N + P +micro
8 10 12
TIME, days
Figure 5. The growth of Selenastrum in Lake Ontario water.
-------
growth in water samples with phosphorus (100 yg P/l final
concentration) was observed. The addition of phosphorus
(100 yg P/l) and nitrogen (1000 yg N/l) increased the growth
to a greater extent. It is possible that the addition of
phosphorus alone would have altered the nitrogen:phosphorus
atomic ratio in the sample to create an artificial nitrogen
limited condition which is alleviated in the samples with
phosphorus plus nitrogen additions. This could be one rea-
son for the increased growth in samples with phosphorus
plus nitrogen spikes. A second possible reason is that the
biologically available phosphorus in the lake water may be
below the minimum required concentration levels and the bio-
logically available nitrogen concentration is just above
the minimum required level for the algal growth. Under
these conditions, an addition of phosphorus would increase
the growth while the addition of nitrogen would not in-
crease the growth of algae since the initial phosphorus con-
centration in water is below the minimum required level.
The addition of phosphorus and nitrogen would increase the
growth of algae more than the sample with the addition of
phosphorus alone.
In some of the Lake Ontario samples, the addition of
phosphorus alone did not increase the growth response of the
laboratory algae. A markedly increased growth was observed
in the samples with phosphorus and nitrogen spikes. Such a
condition, where phosphorus and nitrogen are limiting the
algal growth, is possible in Lake Ontario waters where the
total phosphorus concentration is in the lower range (<10 yg
P/l) and the total nitrogen concentration is also low.
Either phosphorus or nitrogen spiking individually will still
keep the other nutrient below the required level for the
algal growth. The addition of both phosphorus and nitrogen
in the same sample will thus alleviate the phosphorus and
21
-------
nitrogen limited conditions and increase the growth of algal
cells. A typical example of such a situation is seen in
Figure 6 which is a plot of absorbance vs time for the wa-
ter sample from Station 75 collected on (July 19, 1972.)
Based on variations on the absorbance values which
correlate with the algal cell counts, nine of 21 samples re-
ceiving phosphate showed greater growth than the incubated
lake water controls. Seventeen of 21 samples showed in-
creased growth in'samples with phosphate plus nitrate addi-
tions .
The Lake Ontario water samples collected from near the
mouth of tributaries showed a growth response similar to the
deeper lake water samples. Figures 7 and 8 show the
growth of Selenastrum in lake water collected near the mouth
of Niagara and Genesee Rivers,- respectively. While the sam-
ple collected near Niagara River showed a phosphorus limited
condition, the water sample from near Genesee River showed
increase in growth in flasks with phosphorus spiked samples
and flasks with nitrogen plus micronutrients added samples.
To assess the growth of "natural" lake algae in Lake
i u
Ontario water, absorbance measurement was replaced by C
technique. The unfiltered lake water was processed as de-
scribed in the experimental procedure. The first sample was
collected from Station 64 in August, 1972. The lake water
sample was spiked with 100 yg P/l or 1000 yg N/l or 100 yg
P/l + 1000 yg N/l or 1000 yg N/l + micronutrients. All
additions were made as 1.25 ml from working solutions to a
50 ml unfiltered lake water sample. A set of lake water
samples without any nutrient additions was also included in
each experiment.
Net carbon fixation results for water samples from
Station 64 are presented in Figure 9. Incubation of lake
water alone and lake water with nutrients for one week did
22
-------
0.7
0.6
0.5
UJ
O
0.4
QQ
sr
w 0.3
DQ
0.2
0.
1 I I I
LAKE ONTARIO STATION 75
JULY 19, 1972
O LAKE WATER (LW)
D LW + P
A LW+ N
O LW + P + N
V LW + micro
* LW + N + micro
8 10
TIME, days
Figure 6. The growth of Selenastrum in Lake Ontario water.
-------
0.6
LAKE ONTARIO RIVER SAMPLE 19 (STATIONED NEAR NIAGARA RIVER)
AUGUST 2,1972
o LAKE WATER ( LW )
D
A LW + N
O LW + P + N
V LW + N + micro
LW + P + N + micro
10 12
TIME, days
Figure 7. The growth of Selenastrum in Lake Ontario water.
-------
0.10
0.9
0.8
0.7
LU
O
z 0.6
<
m
cc
O 0.5
CO
m
<
0.4
0.3
0.2
O.I
~
1
T
T
LAKE ONTARIO RIVER SAMPLE 17 ( STATIONED NEAR GENESEE RIVER)
AUGUST 2, 1972
o LAKE WATER ( LW )
D LW + P
A LW + N
O LW + P + N
? LW + N + micro
• LW+ P + N + micro
16
18
10 12 14
Tl ME, days
Figure 8. The growth of Selenostrum in Lake Ontario water.
20
22
24
-------
ON
o
2000
O
< 1500
X
o 1000
CD
or
o
LU
500
LAKE ONTARIO STATION 64
AUGUST 23, 1972
A-LAKE WATER
B-INCUBATED LAKE WATER
C-LAKE WATER + lOO^g P/l
D-LAKE WATER + lOOO^g N/l
E-LAKE WATER + lOO^g P/l + lOOO^g N/l
F-LAKE WATER+ micronutrients
G-LAKE WATER+ lOOO^g N/l +
micronutrients
B
C D
TREATMENT
Figure 9. Effect of nutrient spiking on the growth of "natural" Lake
Ontario algae in Lake Ontario water
-------
result in increased carbon fixation; however, based on varia-
tions in the C-14 activity values in the light minus dark
bottles, eight of 26 samples receiving phosphate + nitrate
showed significantly greater growth than the incubated lake
water controls at 0.05 confidence level. (95 percent pro-
bability that the response is actually greater than the incu-
bated lake water controls.) For samples with phosphate +
nitrate + micronutrients, seven of seven samples showed sig-
nificantly greater growth than the incubated lake water con-
trols at the 0.05 confidence level. Table 4 gives the
response of growth of lake water culture to different treat-
ments for water samples collected from various locations.
Alum Treatment --
The potential benefit that may be derived from a re-
duction of phosphorus present in Lake Ontario water on the
growth of algae was assessed by studying the algal response
in alum-treated lake water. One-liter water samples in
Imhoff Cones were treated with 5 or 10 ml of alum (10 g/1
of Al? (SO^)-14- HLO), stirred continuously for 30 seconds,
and allowed to settle. After 24 hours, the supernatant was
filtered through 0.45 y pore size filters. The phosphorus
content on the filtered sample was measured to be sure that
phosphorus had been removed by alum treatment. Fifty ml
samples of filtrate were taken in 120 ml Erlenmeyer flasks
and treated with 100 yg P/l or 100 yg P/l + micronutrients.
A set of controls of filtered alum-treated lake water was
used in each experiment. All treatments and controls were
run in triplicates. One ml of untreated lake water was
added as "seed" to all the test flasks. After seven days
14 =
of incubation, the samples were spiked with C-C03 and in-
cubated in light and dark environments for four hours. The
14
difference in the C counts taken between the light and
dark bottles in each set of treatment was used to assess the
algal growth.
27
-------
Table 4 ^ RESPONSE OF INCUBATED TREATED SAMPLES RELATIVE TO
INCUBATED LAKE WATER SAMPLES
to
00
Station Response
No effect
10 Stimulation
No effect
4-5 Stimulation
No effect
75 Stimulation
No effect
64 Stimulation
No effect
93 Stimulation
10 P 25 P 100 P
333
000
222
000
333
000
- - 1
0
1
- - 0
* Treatment
150 N 375 N 1000 N
323
Oil
222
000
332
001
- - 1
- - 0
- - 1
0
10 P + 25 P + 100 P +
ISO N, 375 N 1000 N
223
110
122
100
222
111
0
1
1 0
1
100 P +
1000 N +
MicroNu.
0
4
0
1
0
2
-
-
-
-
* All treatments are given in pg/1.
- = No Analysis. *
-------
The results of alum-treated experiments indicated a
lack of growth stimulation of the "natural" phytoplankton in
the alum-treated Lake Ontario water. A stimulatory effect
was observed on alum-treated lake water samples spiked with
phosphorus or phosphorus + micronutrients. The results are
summarized in Table 5, For the water samples collected in
March, April, and May of 1973, from Stations 10, 45, and 75,
stimulatory effect on the growth of natural algae was seen
in both phosphorus or phosphorus + micronutrients spiked
samples. Except in two cases, all were significant at 0.05
confidence level.
Tributaries
Niagara River--
A total of 11 water samples was collected from Niagara
River, seven of which were from near Fort Niagara and four
from near Beaver Island. The total phosphorus concentrations
were in the range of 8 to 86 yg P/l. Most of the samples
had concentrations between 20 and 30 yg P/l of total phospho-
rus. Algal Assay Procedure (AAP) tests were run on these
samples and the results showed an increase in algal growth
in phosphorus-spiked samples. These results are tabulated in
Appendix B. A typical relationship of absorbance vs time
for Sample 57 collected on June 15, 1973, is given in Figure
10. Figures H and 12 present typical results obtained
on other days for the Niagara River samples.
Sample 41 from Niagara River had low total phosphorus
(22 yg P/l) and total nitrogen concentration (0.45 mg N/l).
The AAP results presented in Figure 12 show an increase in
growth response with phosphorus addition to the sample. A
greater increase in growth was observed in samples with phos-
phorus plus nitrogen spikes. Sample 50 (Figure 12) had low
total phosphorus concentration (26 yg P/l) and higher total
nitrogen concentration (0.82 mg N/l). The AAP results show
an increase in growth in samples with phosphorus spikes.
29
-------
Table 5, EFFECT OF ALUM TREATMENT ON THE GROWTH
OF "NATURAL LAKE ALGAE IN LAKE ONTARIO
WATER
Treatment
Station
10
45
75a
75
10
75
45
75
Collected
1 April 73
1 April 73
1 April 73
1 April 73
2 May 73
2 May 73
6 May 73
6 May 73
Alum +
LOO yg P/1
ST*
ST
ST
NE**
ST
ST
ST
ST
Alum +
100 yg P/1 +
Micronutrients
ST
ST
ST
ST
NE
ST
ST
ST
All but one sample received 100 mg of alum
(A12 fsoj3 ' l^ H20)/l of sample. One water
sample from Station 75 (1 April 73) was treated
with 50 mg/1 of alum
* ST = Stimulation
**NE = No effect in comparison to the alum
treated sample.
The sample with phosphorus plus nitrogen did not show greater
increase in growth when compared with the results from»the
flasks with phosphorus spikes only.
In Sample 50, the nitrogen concentration was high enough
not to limit the algal growth. In Sample 41, the available
nitrogen concentration could possibly be at the borderline
of minimum required concentration. Therefore, when nitrogen
was added to the sample along with phosphorus, an increased
30
-------
0.
NIAGARA RIVER SAMPLE
JUNE 15, 1973
X RIVER WATER(RW)
0 RW + 25P
• RW + IOOP
A RW + 250N
A RW + IOOON
o RW + 25P + 250N
• RW + IOOP + IOOON
O RW + IOOON + micro
$ RW+ lOOP + IOOON + micro
6 8 10
TIME, days
Figure 10. The growth of Selenastrum in Niagara River water.
-------
OJ
ro
0.7
0.6 -
NIAGARA RIVER SAMPLE 41
APRIL 30, 1973
O RIVER WATER(RW)
D RW + P
A RW + N
O RW + P + N
A RW + N + micro
RW + P + N + micro
24 6 8 10 12 14
TIME,days
Figure II. The growth of Selenastrum in Niagara River water.
-------
0.7
I I I
NIAGARA RIVER SAMPLE 50
MAY 27, 1973
O RIVER WATER ( RW)
D RW + P
A RW + N
O RW + P + N
RW + N + micro
RW + P + N + micro
0
6 8 10
TIME, days
Figure 12. The growth of Selenastrurn in Niagara River water.
-------
growth was observed in Sample 41.
All 11 samples from Niagara River showed phosphorus-
limited condition as determined by the growth of Selenastrum.
Some water samples which had low total nitrogen concentration
showed an increased algal growth response in flasks with
phosphate + nitrate spikes. These results are similar to
the results obtained with Lake Ontario water samples.
Genesee River --
Six samples were collected from Genesee River near
Rochester and the total phosphorus concentrations were in the
range of 105 to 386 yg P/l and the total nitrogen concentra-
tions were in the range of 0.69 to 2.26 mg N/l. AAP tests
were run on all these samples and the results are tabulated
in Appendix c. With the exception of one sample (34),
the Genesee River water samples showed increased growth re-
sponse with the addition of nitrogen in the presence of micro-
nutrients. A typical growth response curve is presented in
Figure 13. The growth of Selenastrum as measured by ab-
sorbance did not show any change when phosphorus was added
to the river water samples, but there was an increased growth
when nitrogen plus micronutrients were added to the river
water samples.
These results indicate a possible nitrogen limitation
in the samples collected from Genesee River. It should be
noted, however, that only six samples were obtained from
•Genesee River over a period of one year, four of them collec-
ted during March - June 1973 and more samples should b« as-
sayed before any conclusion can be drawn about the annual
cycle of nitrogen and phosphorus limitation in these waters.
Oswego River --
During July 1972 through June 1973 , eleven water samples
were collected from the Oswego River. The total phosphorus
concentrations were in the range of 80 to 306 yg P/l and
34
-------
0.7
0.6
0.5
UJ
O
Z
2 0.4
or
o
CO
00
< 0.3
0.2
O.I
0
T
GENESEE RIVER SAMPLE 42
APRIL 30, 1973
o RIVER WATER (RW)
D RW + P
A RW+ N
O RW+ P + N
A RW + N + micro
• RW +.P + N + micro
0
12
14
16
2 4 6 8 10
TIME,days
Figure 13. The growth of Selenastrum in Genesee River water.
18
-------
the total nitrogen concentrations were in the range of 1.16
to 2.30 mg N/l. AAP tests were run on all of these samples
and the results are tabulated in Appendix D,
The results from the- AAP tests on Oswego can be sepa-
rated into two sets. Seven samples showed no increase in
growth of Selenastrum with any of the added nutrients indi-
vidually or in combinations. The algae showed good growth
response in all the samples including the control river
water samples. This indicates nutrient enriched condition
in these water samples. A typical growth curve is presented
in Figure 14-, Although a slight change in the growth is
noted for different treatments as seen by the family of
curves, the overlap of absorbance values of one treatment
on the other indicates no significant change in growth re^
sponses of various treatments. On the other hand, four of
the Oswego River samples showed a different type of growth
response with various treatments in AAP tests. One of the
test results is plotted in Figures 15 and 16 For
Sample 55, an increased growth response was observed in
flasks with nitrogen with micronutrients. The other treat-
ments which included two concentrations of phosphorus and
two concentrations of nitrogen spiked individually or in
combination did not increase the growth of Selenastrum.
This figure is typical of the other three sets of data ob-
tained with the Oswego River water samples.
Black River --
Six Black River water samples were collected during
July 1972 to June 1973. The total phosphorus concentrations
were in the range of 34 to 99 yg P/l and the total nitrogen
concentrations were in the range of 0.59 to 1.25 mg N/l.
AAP tests were run on all these samples and the results are
tabulated in Appendix E.
All the six samples showed 'an increase in algal growth
36
-------
LO
—I
0.7
0.6
0.5
I I I I
OSWEGO RIVER SAMPLE 28
MARCH 2, 1973
o RIVER WATER(RW)
D R W + P
A R W + N
O R W + P + N
T R W + N+ micro
• RW + P+N + micro
LJ
O
0.4
00
rr
o
CO
GO
0.3
0.2
O.I
14
16
4 6 8 10 12
TIME, days
Figure 14. The growth of Selenastrum in Oswego River water.
18
20
-------
oo
LsJ
O
Z
UJ
O
C/>
LJ
rr
O
14
12
10
8
I I I
OSWEGO RIVER SAMPLE 55
JUNE 4, 1973
XRIVER WATER ( RW)
'DRW + 25P
• RW +
ARW +
ARW+
•QRW +
• RW +
ORW +
• RW +
IOOP
250N
IOOON
25P + 250N
IOOP + IOOON
IOOON + micro
IOOP + IOOON + micro
0
8
10
TIME, days
Figure 15. The growth of Selenastrum in Oswego River water.
-------
U)
0.8
0.7
0.6
UJ
O
0.5
CD
cr
o
CO
GO
0.4
0.3
O.2
O.I
I I I I
OSWEGO RIVER SAMPLE 30
MARCH 20, 1973
o RIVER WATER (RW)
D RW + P
A RW+ N
O RW + P + N
T RW + N + micro
• RW + P+N + micro
8 10 12 14
TIME, days
Figure 16. The growth of Selenastrum in Oswego River water.
-------
when phosphorus plus nitrogen were added to the water
samples. A typical growth curve is shown in Figure 17
for Black River water Sample 53. Neither phosphorus nor
nitrogen added individually increased the growth of
Selenastrum in Black River water samples. The river water
clearly showed phosphorus and nitrogtn limited conditions
in all the six samples.
DISCUSSION
The nutrient«rspiking studies of Lake Ontario and the
Niagara River during the late summer required both nitrogen
and phosphorus for stimulation of growth of the test algae
and "natural" algae. Similar results were observed for the
Black Riveri These results indicate both nitrogen and phos-
phorus are limiting planktonic algal growth in Lake Ontario
and at these river mouths.
The samples of the Genesee and Oswego Rivers showed, in
general, nitrogen stimulation. Also, many of the samples
from these rivers demonstrated stimulation due to the addi-
tion of the micronutrients solution used in the NAA media
for the AAP Procedure. Further, many of the samples studied
in this investigation showed both N £ P stimulation at a
high level of N £ P addition. Results of this type must be
examined in light of the conditions of the test. In a bio-
assay of this type, it is possible to make any element lim-
iting by adding large amounts of other essential elements
and providing sufficient light for growth. Proper inter-
pretation of the data for this type of bioassay requireS that
one consider the stimulation, or lack thereof, when small
amounts of a potential-limiting element are added.
Care must also be exercised in interpreting the micro-
nutrient stimulation data found for the Genesee and Oswego
Rivers. The micronutrient solution also contains EDTA, a
strong complexing agent. There is increasing evidence that
40
-------
0.7
0.6
0.5
UJ
O
CD
0.4
0.3
CD
0.2
O.I
0
0
I I I I
BLACK RIVER SAMPLE 53
MAY 28, 1973
O RIVER WATER (RW)
D R W + P
A RW + N
O RW + P+ N
A RW + N +micro
• R W + P +N + micro
I
6 8 10
TIME, days
12
14
16
Figure 17. The growth of Selenastrum in Black River water.
-------
algal growth in many waters near urban centers is inhibited
by toxic elements in the water- Often, this toxicity can
be eliminated by addition of a complexing agent. The stimu-
lation noted in this study by the micronutrient solution may
have been due to a removal of toxicity present in the water
by the EDTA in the solution. Additional study of these waters
in which the various components of the micronutrient solution
are tested individually or in certain combinations must be
conducted before it will be possible to ascertain what is
the cause of the stimulation.
The results of this investigation provide valuable infor-
mation on the approaches that should be used to reduce the
excessive algal growth in Lake Ontario. Since essentially
all lake water samples showed phosphorus limitation, efforts
should be directed to limiting potentially available phos-
phorus inputs to the lake. The fact that the Lake Ontario
open water samples taken during late summer showed both phos-
phorus and nitrogen limitation does not change the excessive
fertilization control strategy since, in general, nitrogen
control is considerably more difficult and expensive than
phosphorus control.
Based on the results of this study, it is concluded that
a substantial reduction of immediate potentially available
phosphorus will tend to reduce planktonic algal growth in
Lake Ontario. It is readily apparent, based on the estimated
phosphorus sources, that immediate steps should be taken to
provide advanced waste treatment removal of P from all major
domestic wastewater sources entering Lake Ontario or its
tributaries from the U.S. and Canada.
Phosphorus removal from domestic wastewaters by advanced
waste treatment methods may not result in reduced algal
growth in tributary rivers and nearshore regions or near ur-
ban centers of the lake such as Rochester and the Genesee and
Oswego Rivers because phosphorus is not currently limiting
42
-------
algal growth. It is possible that phosphorus removal at
domestic wastewater treatment plants located in these areas
could be sufficient to cause phosphorus to be limiting. It
is also possible that advanced waste treatment could reduce
the concentration of the apparent toxicant present in these
rivers which would stimulate algal growth in the river and
nearshore waters due to the excess phosphorus present.
There is a need for a more detailed assessment of factors
limiting algal growth in these waters and relative nutrient
sources before reliable predictions can be made on the en-
vironmental impact of advanced waste treatment of domestic
wastewaters in the Genesee and Oswego River basins. Even
though the potential impact of phosphorus removal cannot be
predicted for these rivers and nearshore waters of Lake
Ontario, it is clear that such a practice will be of some
benefit in reducing the rate of and possibly reversing the
algal growth in Lake Ontario.
43
-------
REFERENCES
National Eutrophication Research Program. 1971. Algal
Assay Procedure Bottle Test. U.S. Environmental
Protection Agency, Corvallis, Oregon. 82 p.
44
-------
SECTION VII
APPENDICES*
Appendix Page
A Algal Bioassays for Lake Ontario Water 3
B Algal Bioassays for Niagara River Waters 37
C Algal Bioassays for Genesee River Waters 52
D Algal Bioassays for Oswego River Waters 61
E Algal Bioassays for Black River Waters 77
*In order to reduce printing costs,appendices have not been included in
this report. However, they may be purchased in paper or microfiche copy
from the National Technical Information Service, U.S. Department of Commerce,
Springfield VA 22151.
45
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/3-77-046a
3. RECIPIENT'S ACCESSI ON-NO.
4. TITLE AND SUBTITLE,
AND
ALGAL NUTRIENT AVAILABILITY
LIMITATION IN LAKE ONTARIO DURING IFYGL
Part III. Algal Nutrient Limitation in Lake Ontario
During TFYGL. -
5. REPORT DATE
Mav 1977 (Issuing date)
6. PERFORMING ORGANIZATION CODE
7. AUTHORfST
Nagalaxmi
8. PERFORMING ORGANIZATION REPORT NO
Sridharan* and G. Fred Lee
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Center for Environmental Studies
University of Texas at Dallas
Richardson, Texas 75080
10. PROGRAM ELEMENT NO.
1BA608
11. CONTRACT/GRANT NO.
Contract
R-800537-02
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
Environmental Research Laboratory-Duluth,
Office of Research and Development
U.S. Environmental Protection Agency
Duluth, Minnesota 55804
Final
14. SPONSORING AGENCY CODE
EPA/600/03
15. SUPPLEMENTARY NOTES
^University of Wisconsin
Madison, Wisconsin 53706
16. ABSTRACT
This study was conducted on
and micronutrients in limiti
major tributaries. Standard
open waters of Lake Ontario
showed phosphorus limitation
and phosphorus limitation.
limitation. Samples of the
limitation.
the potential significance of nitrogen, phosphorus
ng planktonic algal growth in Lake Ontario and its
algal assay procedures were used. Samples of the
and Niagara River waters collected during the spring
By late summer these waters showed both nitrogen
Genesee and Oswego Rivers showed, in general, nitrogen
Black River Waters showed both nitrogen and phosphorus
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Nitrogen
Phosphorus
Plankton
Nutrients
Lake Ontario
06 C, F
08 H
13. DISTRIBUllON STATEMENT
Release to Public
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
58
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
46
U S. GOVERNMENT PRINTING OFFICE 1977-757-056/61)19 Region No. 5-1
------- |