PA-902/9-73-002
LAKE ONTARIO
ENVIRONMENTAL SUMMARY
1965
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION II
ROCHESTER FIELD OFFICE
ROCHESTER, NEW YORK
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LAKE ONTARIO
ENVIRONMENTAL SUMMARY
1965
by
Donald J. Casey
William Fisher
Conrad 0. Kleveno
U. S. Environmental Protection Agency
Region II
Rochester Field Office
Rochester, New York
The opinions and professional judgments expressed in this
paper are those of the authors, and do not necessarily express
the views and policies of the U. S. Environmental Protection Agency.
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PREFACE
This report on Lake Ontario water quality was written in 1966.
Several scientists involved in the International Field Year for
the Great Lakes program, who were aware of the draft report, sug-
gested that the material be made available to document historical
data on the water quality of the lake.
The report contains conclusions which are based on the data as
originally collected. It is recognized that subsequent investigations
may have resulted in information and conclusions which differ from
some of the material in this report. However, no effort has been
made to update the report. It is published here as it was written
in 1966.
At the time this report was prepared, the Federal water pollution
control program was being carried out by the Federal Water Pollution
Control Administration. The material for the report was assembled
by the staff of what was at that time the Lake Ontario Program Office,
which was part of FWPCA's Great Lakes Region, under the direction of
Lee Townsend. His efforts, as well as those of other members of the
staff who made this report possible, are gratefully acknowledged.
In 1970, when the Environmental Protection Agency was formed,
the former Lake Ontario Program Office became the Rochester Field
Office of Region II of EPA.
K. H. Walker, Director
Rochester Field Office
May 1973
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TABLE OF CONTENTS
Page No.
1 INTRODUCTION
Purpose 1-1
Area of Interest 1-1
Deep Water Sampling 1-1
Related Work 1-2
Acknowledgments 1-3
2 LAKE ENVIRONMENT
Morphometry . 2-1
Hydrology 2-2
Climate 2-4
Geology 2-5
Sediments 2-5
Physical 2-5
Chemical 2-6
3 BIOLOGY OF LAKE ONTARIO
Introduction 3-1
Benthic Fauna 3-1
Amphipoda 3-2
Oligochaeta 3-2
Phytoplankton 3-3
Diatoms 3-4
Chlorophyll 3-4
Cladophora 3-6
Fishing 3-8
Trophogenic Zone 3-10
4 MICROBIOLOGY
Introduction 4-1
5 CHEMISTRY
Introduction 5-1
Nitrogen 5-2
Ammonia Nitrogen 5-4
Nitrite 5-5
Nitrate Nitrogen 5-5
Organic Nitrogen 5-6
General Discussion 5-7
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TABLE OF CONTENTS (Cont'd)
Page No.
Phosphorous (Phosphate) 5-8
Soluble Phosphate 5-9
Total Phosphate 5-10
General Discussion 5-11
Phosphate Removal At Treatment Plants 5-15
Hydrogen-ion Concentration (pH) 5-17
Dissolved Oxygen 5-20
Chlorides 5-22
Silicon 5-24
Sodium 5-26
Biochemical Oxygen Demand (BOD) 5-27
Dissolved Solids 5-27
Potassium 5-28
Conclusion 5-28
PHYSICAL CHARACTERISTICS
Introduction 6-1
Factors Governing Water Circulation 6-2
Winds 6-2
Temperatures 6-4
Currents 6-9
Littoral Drift 6-12
Bottom Currents 6-13
Rochester Embayment 6-14
Temperatures 6-15
Currents 6-16
SUMMARY AND CONCLUSIONS
Summary 7-1
Morphology 7-1
Biology 7-2
Chemistry 7-3
Physical 7-7
Conclusions 7-9
BIBLIOGRAPHY
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LIST OF ILLUSTRATIONS
Chapter 1
Introduction
Figure 1-1 Chart showing biological and chemical sampling
stations in Lake Ontario
Chapter 2
Lake Environment
Figure 2-1 Bathymetric chart of Lake Ontario
2-2 Hypsometric curve of Lake Ontario
2-3 Mean Annual precipitation of Lake Ontario basin
Chapter 3
Biology of Lake Ontario
Figure 3-1 Distribution of Amphipoda; Cruise 102
3-2 Distribution of Amphipoda; Cruise 103
3-3 Distribution of Amphipoda; Cruise 104
3-4 Distribution of Diatoms; Cruise 102
3-5 Distribution of Chlorophyll; Cruise 102
3-6 Distribution of Chlorophyll; Cruise 103
3-7 Distribution of Chlorophyll; Cruise 104
3-8 Trophogenic zone; Cruise 102
3-9 Trophogenic zone; Cruise 103
3-10 Trophogenic zone; Cruise 104
Chapter 4
Microbiology
Figure 4-1 Total plate count at 20°c; Cruise 102
4-2 Total plate count at 20°c; Cruise 103
4-3 Total plate count at 35°c; Cruise 102
4-4 Total plate count at 35°c; Cruise 103
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Chapter 5
Chemistry
Figure 5-1 Relation of Nitrate, Ammonia and Organic
Nitrogen in Lake Ontario Surface Water
Cruise 102
5-2 Relation of Nitrate, Ammonia and Organic
Nitrogen in Lake Ontario Surface Water
Cruise 103
5-3 Relation of Nitrate, Ammonia and Organic
Nitrogen in Lake Ontario Surface Water
Cruise 104
5-4 Surface Distribution of Ammonia
Cruise 102
5-5 Surface Distribution of Ammonia
Cruise 103
5-6 Surface Distribution of Ammonia
Cruise 104
5-7 Surface Distribution of Nitrate
Cruise 102
5-8 Surface Distribution of Nitrate
Cruise 103
5-9 Surface Distribution of Nitrate
Cruise 104
5-10 Surface Distribution of Organic Nitrogen
Cruise 102
5-11 Surface Distribution of Organic Nitrogen
Cruise 103
5-12 Surface Distribution of Organic Nitrogen
Cruise 104
5-13 Distribution of soluble phosphate
Cruise 102
5-14 Distribution of soluble phosphate
Cruise 103
5-15 Distribution of soluble phosphate
Cruise 104
5-16 Distribution of total phosphate
Cruise 103
5-17 Distribution of total phosphate
Cruise 104
5-18 Hydrogen ion (pH) concentration
Cruise 102
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Figure 5-19 Hydrogen ion (pH) concentration
Cruise 103
5-20 Hydrogen ion (pH) concentration
Cruise 104
5-21 Dissolved oxygen, percent of saturation at the
surface; Cruise 102
5-22 Dissolved oxygen, percent of saturation at the
bottom; Cruise 102
5-23 Dissolved oxygen, percent of saturation at the
surface; Cruise 103
5-24 Dissolved oxygen, percent of saturation near the
bottom; Cruise 103
5-25 Dissolved oxygen, percent of saturation at the
surface; Cruise 104
5-26 Dissolved oxygen, percent of saturation near the
bottom; Cruise 104
5-27 Distribution of chloride
Cruise 102
5-28 Distribution of chloride
Cruise 103
5-29 Distribution of chloride
Cruise 104
5-30 Chart showing surface distribution of silica
dioxide; Cruise 102
5-31 Chart showing surface distribution of silica
dioxide; Cruise 103
5-32 Chart showing surface distribution of silica
dioxide; Cruise 104
Chapter 6
Physical Characteristics
Figure 6-1 Schematic diagram showing the make-up of a typical
current metering station
6-2 Net surface circulation during period of stratification
and net wind direction
6-3 Polar histograms of Sta. 18, showing net flow for
period of August to October 1964
6-4 Temperature profiles for the month of August
6-5 Spring thermal bar with associated vertical circulation
6-6 Surface temperatures; Cruise 102
6-7 Surface temperatures; Cruise 103
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Figure 6-8
6-9
6-10
6-11
6-12
6-13
6-14
6-15
6-16
6-17
6-18
6-19
6-20
Northeast wind
East wind
Southeast wind
Surface temperatures; Cruise 104
Circulation of Lake, North wind
Circulation of Lake,
Circulation of Lake,
Circulation of Lake,
Circulation of Lake,South wind
Circulation of Lake, Southwest wind
Circulation of Lake, West wind
Circulation of Lake, Northwest wind
Littoral Drift
Bottom drift as interpreted from sea-bed drifters
Rochester embayment
Graph showing relation of winds and currents
in Rochester embayment, Station 19
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Chapter 1
INTRODUCTION
.Purpose
The purpose of this report is to provide a summary of the
results of the chemical, biological, and physical studies of Lake
Ontario. These studies were conducted by the Lake Ontario Program
Office, Great Lakes Region, Federal Water Pollution Control Adminis-
tration, U.S. Department of the Interior, in cooperation with the
New York State Health Department, Monroe County Health Department,
U.S. Corps of Engineers, and U.S. Geological Survey.
Areas of Interest
This report deals with the deep water areas of Lake Ontario.
A separate report entitled "Minor Tributaries Area" will deal with
the shallower water areas. This report includes biological and
chemical data obtained from three sampling cruises conducted by the
Lake Ontario Program Office, using the Corps of Engineers vessel
T-501. Physical and sedimentary data were obtained from the T-501
cruises and the three separate phases of operation carried out by
the physical oceanography section.
Deep Water Sampling
Three major sampling cruises were conducted by the Lake Ontario
Program Office during 1965, using the Corps of Engineers 60-foot
vessel T-501. This vessel was equipped with laboratory facilities
for microbiological, biological, and chemical work. At the time of
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sampling, physical parameters such as air temperatures, wind velocity,
and water temperatures were also recorded.
Forty-two stations (Figure 1--1) were sampled in May, Cruise 102;
late July-early August, Cruise 103; and in late September-early
October, Cruise 104. Cruise 101 was carried out while setting the
first series of current-metering stations in August 1964. The purpose
of Cruise 102, 103, and 104 was to gather data on the various chemical,
biological, and physical parameters of the lake. Cruise 101 was a
reconnaisance sampling cruise to gather background data to help in
planning the three major cruises. Data from Cruise 101 have not been
included in this report.
Related Work
The lake study was conducted as part of the development of a
comprehensive water pollution control program for the Lake Ontario
Basin, which is documented in several sub-basin reports. Each of
these reports presents a survey of major pollution problems, water
uses and trends in water usage, and presents a program for the abate-
ment of water pollution in the Basin.
The reports are titled: "A Water Pollution Control Program for
the Black and U.S. St. Lawrence River Basins", "A Water Pollution
Control Program for the Genesee River Basin", "A Water Pollution
Control Program for the Minor Tributary Basins of Lake Ontario",
1-2
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HAMILTON
BIOLOGICAL and CHEMICAL
SAMPLING STATIONS
in
LAKE ONTARIO
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and "A Water Pollution Control Program for the Oswego River Basin".
Acknowledgments
The assistance of the Lake Ontario Program Office staff is
gratefully acknowledged. Especially helpful were: Mr. Lawrence R.
Mori arty, assistant director, and Mr. Thomas Kamppinen who drafted
most of the illustrations.
Particular thanks go to Mr. Robert Hartley, Mr. Robert Booth,
and Mr. Wesley Kinney of EPA; and Dr. Robert Sweeney, SUNY at Buffalo
Dr. Fred G. Lee, University of Wisconsin, and Dr. Keith Rodgers,
University of Toronto, all of whom reviewed this report and gave
continued encouragement to the authors.
1-3
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Chapter 2
LAKE ENVIRONMENT
Morphometrv
Lake Ontario is a relatively narrow deep lake with its long axis
aligned in an east-west direction. The lake, Figure 2-1, is approxi-
mately 190 miles (305 km) long and 53 miles (85 km) wide. Its greatest
depth is 840 feet (256 meters); the average depth is 300 feet (91
meters). The total volume of the lake is 390 cubic miles (1628 cubic
km); 85 percent of this volume is below the thermocline in summer.
The surface area of the lake is 7,600 square miles (19,684 sq. km),
and its basinal area,is 34,800 square miles (90,130 sq. km). The
elevation of the lake's surface is 245 feet above sea level, and
its deepest part is approximately 600 feet (185 meters) below sea
level.
Lake Ontario, Figure 2-1, can be considered to have two longi-
tudinal basins: the western basin comprises almost two-thirds of
the lake and has a maximum depth of 630 feet (192 meters), and the
other at the eastern end of the lake has a maximum depth of 840 feet
(256 meters ). The deeper basin, while smaller, is more sharply
defined. A ridge, which appears to be geologically controlled,
separates the basins with a maximum sill depth of 540 feet (165 meters).
2-1
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HAMILTON
BATHYMETRIC CHART OF
LAKE ONTARIO
NOTE. DEPTH IN FEET
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The difference in depth between the two basins can be explained by a
difference in sedimentation rates. This would also account for the
more gentle bathymetry of the western basin. The southern side of
the lake is steeper than the northern side, due to differentiated
glacial scour during Pleistocene time.
Figure 2-2 is a hypsometric curve for Lake Ontario proper,
excluding the bay-like area northeast of Duck Island. Inasmuch as
the curve is almost linear, the percent of surface area can be inter-
preted as percent of volume. One very important physical characteristic
of Lake Ontario is apparent: the large volume of water mass per unit
surface area. If we assume that the average depth to the thermocline
is 70 feet (21 meters), then 85 percent of the lake's water mass
is below the epilimnion. In comparison, the situation is nearly reversed
in Lake Erie. This physical characteristic has far-reaching effects
on the chemical and biological systems within the lake. For example,
a large reserve of oxygen exists in the hypolimnion, so it is unlikely
that a serious overall depletion of oxygen will occur; however, this
should not be taken to mean that serious local depletion will not occur.
As regards the biota, a relatively small surface growing area
exists in comparison to the volume of the water mass; thus, Lake Ontario
has a large nutrient reserve in comparison to the growing area.
2-2
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PERCENT OF SURFACE AREA
100
90
l
80
I
70
60
50
I
40
I
30
I
20
10
100-
2OO-
SEA LEVEL
300-
lU
U
u.
- 400-
I
I-
0.
u
Q 500-
600-
700-
SURFACE
HYPSOMETRIC CURVE
LAKE ONTARIO
aoo
IV
,
7000
1
6000
50OO 40OO 3000
AREA IN SO. Ml.
1
2000
1000
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Also, with the large oxygen reserve available in Lake Ontario, it
would require a very large amount of phytoplankton production in the
surface waters to cause a generalized depletion of dissolved oxygen
in the hypolimnion of Lake Ontario. The effects of the basin's
physical shape on the chemical, biological, and physical characteristics
of the water mass will be discussed further on in this report.
Hydrology
The Niagara River, Table I, with a mean annual inflow into Lake
Ontario of approximately 200,000 cfs, is by far the greatest hydrologic
factor influencing the lake environment. The distribution of this flow
is quite even because of the dampening influences caused by the upstream
lakes and regulation by power plants, and the result is that an essen-
tially steady state gradient flow is constantly imposed on Lake Ontario,
extending from the river's mouth to the lake's outlet at the St.
Lawrence River.
Other major rivers are few in the Lake Ontario Basin. They are
the Oswego River, which drains the Finger Lakes Region; the Genesee River.
which drains the Appalachian Front; the Black River, which drains the
western Adirondack Mountains; and the Trent River, draining part of
Ontario,Canada.
2-3
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Table I
WATER BUDGET
Niagara River 203,000 cfs
Small rivers 19,500 cfs
Rainfall 18,000 cfs
Oswego River 6,500 cfs
Black River 3,900 cfs
Trent River 3,100 cfs
Genesee River 2,800 cfs
St. Lawrence River 238,000 cfs
Evaporation 18,800 cfs1
Volume of Lake Ontario 391 cubic miles
Average Residence Time
391 miles3 _ ,
~ 8'4
219,000 cfs net
1 Bruce, J. P. and Rodgers, G. K. , 1962
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The smaller creeks and rivers draining the sedimentary rocks
along Lake Ontario have flows that are characteristic of limestone
terrains, with high spring runoff and very low summer flows. In the
summer months, almost all of these streams, because of sluggish flow
and pollution, develop such prolific growths of algae and duckweed
that very little open water can be seen near their mouths.
The mean annual precipitation in the lake basin is approximately
33 inches, Figure 2-3. The lowest values occur in the west-central
part of the basin and the highest values in the area of the Adirondack
Mountains and the Appalachian Front.
The retention time for water entering the lake (using the refill
method) is on the order of eight years. The actual retention time, how-
ever, is affected by the effects of stratification and net circulation.
Water in the deeper parts of the lake is retained for very long periods.
The retention time, considering such factors as circulation, the effects
of stratification, and that outflowing waters are a mix of Lake Erie and
Lake Ontario waters, etc., is over 15 years.
Climate
Although the Lake Ontario Basin is considered to have a continental
climate, the lake has a moderating effect and brings to the area in-
fluences of a marine climate that are apparent in such elements as
2-U
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t
,1
TORONTO '
HAMILTON
-N-
\
10 20
N
in
•32"
\
ROCHESTER,
Bay
, NIAGARA FALLS
S
cv
n
BUFFALO
NEW
YORK
Boy
J
co
\'*
\
\
A
/ i
OSWEGO
/ j >
MEAN ANNUAL
PRECIPITATION
LAKE ONTARIO BASIN
NOTE! Prtclpitotion in inchr*.
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temperature and humidity, and the usual effects of land and lake breezes.
During the summer months the lake stores up heat (the maximum heat
content of the lake occurs after the maximum surface temperatures are
reached. See G. K. Rodgers and D. V. Anderson.) which is released to
the atmosphere during the late fall and early winter as it cools, thus
delaying the onset of cold weather. In the spring the reverse is true;
the cold lake waters take up heat by cooling the air masses and delay
the onset of warm weather. Upper and lower extremes of temperature are
modified by this lake effect so that the daily, as well as the long-
term, range of temperature is less than normal at this latitude. The
average range is between 70°F. (21°C) in July and 25°F, (-4°C) in
February. Summer temperatures rarely reach 100°F. (38°C), and the
winter minimum rarely reaches 0°F. (-18°C). The lake effect also
increased the cloudiness during cold weather, when air masses that are
warmed, and whose moisture content increased in passing over the lake,
are cooled upon striking the cooler land mass. Snowfalls, so caused,
are frequent and sometimes severe.
Another factor governing the area's climate is the St. Lawrence
storm track. Cyclonic systems passing up this track bring in moisture
from the Gulf of Mexico and are the principal source of rainfall in the
area.
2-5
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Geology
Lake Ontario lies wholly in Paleozoic rocks of Ordovician Age
excavated along the axis of a former valley by glaciers in Pleistocene
time. At one time in the past, geologically speaking, the lake basin
was actually an arm of the sea.
The axis of the lake is oriented parallel to the strike of the
rocks, which dip southward. Along the southern side of the lake, the
Niagara dolomite, sharply defined at Niagara Falls, forms a rim that
gradually disappears in an easterly direction. The deeper part of the
lake, to the south of center, was excavated in the less resistant
Queenstown shale. The northern part of the lake basin is underlain
by older and more resistant limestone.
The superficial geology of the basin is the result of marine,
glacial, and lake deposition and erosion.
Sediments
Physical
During July 1965, sediment samples were collected on a 10-mile
(16 km) spacing throughout the lake. Sand mixed with boulders and
pebbles was found all along the edge of the lake from the shore line
out to depths of 77 feet (22 meters) or more. (So-called shingle
beaches are common along the southern shore line.) Most of this material
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comes from the numerous glacial and bedrock (shale) deposits found
along the shore. On the Canadian side, these deposits are much more
extensive; in some areas sand is found out to depths of 200 feet
(61 meters). Near Scotch Bonnet Shoal there is a large extensive
shelf area with numerous boulders and pebbles mixed with reddish
sand. This shelf area extends from Colbourne, Ontario, around the
eastern rim of the lake to the southwestern end of Mexico Bay.
From the edge of the sand deposits, the sediments grade laterally
from sand to silt to clay, with various mixtures in between.
Sand also was found to be present in the samples obtained from
the deep basins, along with the clays and silts. The source of the
sand in these samples appears to be wind-blown material because of
the fresh-looking fractures and angular shapes. Sediments from two
sources are being deposited in the deep basins: those derived from
stream and shore erosion and a wind-carried fraction.
Chemical
Twenty-five sediment samples from Cruise 103 and 34 samples from
Cruise 104 were analyzed for several parameters, two of which were
total iron and total phosphate. The results of this study suggest
that the amount of phosphate in the sediment is related to the amount
of iron in the sediment, since the ratio of phosphate to iron did not
2-7
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vary significantly between the two cruises, while the total amount of
iron did. The amount of iron was less for Cruise 104 than for Cruise
103 on a station-to-station comparison. This consistent difference
cannot be attributed to a laboratory error inasmuch as three analytic?
separate runs were made using samples from both cruises for each run.
The mean percent of interstitial water by weight for these
sediment samples was 60 and ranged from a high of 68 percent to a low
of 20 percent. The amount of interstitial water appears to be related
to the depth from which the sample was taken; the greater the depth,
the more interstitial water.
Where enough of this interstitial water could be obtained for'a
valid result, analysis for iron and phosphate was made. The results
of this study, when compared to the lake waters, show that phosphate
was higher in the interstitial waters, on the average, by a factor of
10. Analysis for iron was not made in the water sampling cruises, so
no comparison between lake water and interstitial water can be made
for iron. The amount of iron in the interstitial water averaged
.037 mg/1.
2-8
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Chapter 3
BIOLOGY OF LAKE ONTARIO
Introduction
The biota of Lake Ontario are of great importance, for they
represent the overall effect on the environment of a series of chemical
and physical systems existing in the lake. Changes in the biota can
be, and often are, detected before measurable changes occur in, for
example, the chemistry. They can often mask any changes that have
occurred in the lake chemistry as well.
Benthic Fauna
The benthic fauna of Lake Ontario is comprised of six principal
organisms. Two types, Amphipoda (scuds) and Oligochaeta (sludgeworms)
constituted 95 percent of all organisms collected; the remaining 5
percent consisted of Sphaeriidae (fingernail clams), Chironomidae
(bloodworms), Isopoda (aquatic sow bugs), and Hirudinea (leeches),
in order of importance. Amphipoda were dominant organisms at all
stations except number 10, near the mouth of the Niagara River.
The range in numbers of organisms per square meter varied from 0
to 5,400, of which scuds and sludgeworms comprised approximately 70
percent and 20 percent, respectively, at the deep-water stations.
Areas where greater numbers of biota generally existed were the
3-1
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western end of the lake (in the Toronto-Hamilton-Niagara River area)
near the mouths of the Genesee, Oswego, and Black Rivers, and Mexico
Bay.
Inasmuch as the sampling stations were 10 to 15 miles (16 to 24
apart, these biological data should be considered only of a general
nature. Sampling should be done on a much denser scale if the areal
extent and gradational distribution of the biota are to be noted. Tl
is particularly true of the benthic fauna where significant changes
quality and quantity of biota occur in short distances. Sampling
phytoplankton can be done on a somewhat wider scale because their
distribution is related more to a particular water mass. However,
such physical factors as the time of day, the type of weather, and
the temperature of the water also govern the type and quantity of tli
organisms present.
Amphipoda (scuds)
Amphipoda are considered to be of an intermediate type as regar
tolerance of pollution. Included also in this category are such
organisms as certain midges, fingernail clams, snails, and dragon f
nymphs. The area! distribution of Amphipoda for Cruises 102, 103,
and 104 is shown in Figures 3-1, 3-2, and 3-3, respectively. The
patchlike patterns are partly due to areal distribution and spacing
sampling sites. Data from all three cruises show a continuous
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10 0 10 20
HAMILTON
DISTRIBUTION OF AMPHIPODA
CRUISE 102
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10 0 10 ZO 30ml
dl
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w
10 0 (0 ZO 30""
HAMILTON
o i K DISTRIBUTION OF AMPHIPODA
CRUISE 104
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distribution of Amphipoda in the eastern end of the lake. The widest
areal distribution was observed during Cruise 104, which also
coincided with the greatest number of Amphipoda observed. The fewest
number of Amphipoda observed was during Cruise 102, Figure 3-1.
The general overall distribution of Amphipoda observed during the
three cruises shows that their greatest number and widest areal
distribution occur in areas of high pollutional (nutrient) input
into the lake.
Oligochaeta (sludgeworms)
The distribution of Oligochaeta, generally considered a pollution'
tolerant organism, was not adequate for presentation on charts since
they varied greatly in quantity and areal extent. Data from Cruise
102 show that Oligochaeta are found in the eastern end of the basin
(count of 200 or less) and in particular off the mouth of the Niagara
River (Station 10), where a count of 4,000 organisms was made.
p
Counts as high as 250 organisms/meter were found in the vicinity
of the Oswego and Genesee Rivers.
Data from Cruise 103 showed a general increase in Oligochaeta
during the summer months in the Toronto-Hamilton area at Station 10
near the mouth of the lake, in the Mexico Bay area off the mouth of
the Oswego River, and at Station 29 (1,000 organisms/meter2) near
3-3
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Scotch Bonnet Shoal. These increases are probably related to an
increase in sediment nutrients and a warming of the muds in the
shallower areas. Sediments that contained the high numbers of
Oligochaeta in general were in a reduced state. Station 23, off
Rochester, showed a marked decrease during the summer for which no
explanation is available.
Data from Cruise 104 show the same areal distribution of Oligochaeta
as Cruise 103, but the quantity declined.
The greatest areal extent of Oligochaeta was observed in the
eastern end of the lake. The highest count was observed near the
mouth of the Niagara River. While it appears Oligochaeta prefer
shallower areas of the lake, they are most widespread in areas of
highest pollutional input (western end) to the lake.
Phytoplankton
The densities of phytoplankton in Lake Ontario ranged from a
minimum of 50 organisms per milliliter to a maximum of 3,600 organisms
per milliliter during the three cruises. In May of 1965, the total
counts were greater than in July or September. These counts reflected
a spring pulse, which consisted predominantly of the green alga
Scenedesmus. During Cruises 103 and 104, the predominant form
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observed was Chlamydomonas, a flagellated green alga. Scenedesmus
and Chiamydomonas are not found as the dominant forms in the other
Great Lakes, with the exception of Lake Erie. Both forms are con-
sidered to be indicative of enriched waters.
Diatoms
The highest densities of diatoms, both centric and pennate
undifferentiated, were observed during Cruise 102 (Figure 3-4).
High densities were found in the western end of the basin (the Toronto-
Hamilton-Niagara River area). The lowest diatom densities were
observed along the southern shoreline. The northeastern area of the
lake showed the greatest areal extent of high diatom counts.
The distribution of the spring pulse of diatoms was related to the
distribution of dissolved silicon dioxide in the water. (See Figure
5-30).
Cruise 103 showed a marked decrease in diatoms which paralleled a
decrease in dissolved silicon dioxide in the water. Cruise 104 showed
a slight recovery in the number of diatoms, but this recovery was not
related to any measured increase in dissolved silicon dioxide. The data
from Cruises 103 and 104 are not displayed on charts because the distri-
bution of diatoms was too scattered.
3-5
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HAMILTON
NOTE! Diatoms /ml.
DISTRIBUTION of DIATOMS
CRUISE 102
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Chlorophyll
Chlorophyll concentrations are indicative of the planktonic concen-
trations present in the water mass inasmuch as the amount of chlorophyll
is related to the photosynthetic process.
Data from Cruise 102 (Figure 3-5) show large amounts of chlorophyll
in the western end of the basin. This probably represents a spring
pulse which also shows up in the chemistry data (Figure 5-21) as an
area where supersaturation values for dissolved oxygen were observed.
The lowest chlorophyll values (less than 5 milligrams/meter^) were
observed in the area of Scotch Bonnet Shoal and appear to be in the
same area where high diatom densities were reported; however, the diatom
population may have been at a different depth than where the chloro-
phyll sample was taken. This distribution pattern corresponds with the
temperature and circulation of the lake observed at the same time.
Data from Cruise 103 (Figure 3r6) show an overall increase in the
chlorophyll. Notable were the high chlorophyll concentrations found
off the Genesee River; whereas both the Niagara and Oswego Rivers showed
no such levels of concentration.
Data from Cruise 104 (Figure 3-7) while incomplete (no samples were
taken east of Sodus Bay), show a further increase in chlorophyll concen-
trations. Values above 10 milligrams/meter are found near the river
mouths, Scotch Bonnet Shoal, mid-lake, and in the Toronto-Hamilton
area. At no time were concentrations below 5 milligrams/meter3 observed,
3-6
-------
N
10 0 10 ZO 30mi.
TORONTO
HAMILTON
DISTRIBUTION OF
CHLOROPHYLL
CRUISE i02
NOTE! CNorophyll inmg.yM3. One meter below turfoce.
-------
Sji
TORONTO
HAMILTON
-N-
10 0 10 X 50""
DISTRIBUTION OF
CHLOROPHYLL
CRUISE 103
NOTE! Chtorophytl In mg./ M?, Ont m«ttr below turf oca
-------
Samples Token
This Area
DISTRIBUTION OF
CHLOROPHYLL
CRUISE 104
NOTE! Chlorophyll in mq./M., One meter below surface
-------
In general, the distribution of chlorophyll concentrations reflects
temperature and circulation patterns at the time of sampling. The
results presented here represent the first lake-wide chlorophyll sampling
carried out on Lake Ontario. Some of the apparent discrepancies, such
as the development of chlorophyll concentrations off the Genesee River
and no apparent concentrations at other stream mouths, may represent
flow conditions or a difference of density between lake and stream
waters, and,because sampling was carried out only at a depth of one
meter, a concentration of plankton at a different depth would have
been missed.
It is felt, however, that with refinement the chlorophyll concen-
trations in conjunction with chemical data (nutrient concentrations)
will enable one to estimate the plankton crop.
Cladophora
Probably the major and most perplexing biological problem in Lake
Ontario is the yearly crop of Cladophbra . The genus Cladophora is an
attached branched filamentous green alga, whose distribution is world-
wide. Along with a sufficient nutrient level, a suitable bottom, such
as rocks or other coarse material, is necessary for the growth of
Cladophora. In Lake Ontario, most nutrient-rich waste effluents are
discharged into the water float on the surface and drift to accumulate
in the inshore areas where the sedimentary material, largely cobble-
stones, affords an excellent bottom for algal attachment
3-7
-------
Prolific growths of Cladophora have been reported in Lake
Ontario as far back as 1932 (Neil and Owen, 1954). The distribution
of Cladophora appears to be governed by water movements, for the growths
are most prolific where currents keep the supply of nutrients high.
Where local conditions tend to hinder water movement, the concentrations
are lower. This alga also appears to be quite tolerant of temperature,
for it is found growing under a wide range of temperatures. Light
penetration governs the depth at which Cladophora are found; in Lake
Ontario it is found at depths of 30 feet or more. On oceanographic
equipment located in mid-lake, growths of Cladophora were found on
current meters located at the 50-foot level. Cladophora also develop
best in an environment where pH (Prescott's findings may be misleading,
inasmuch as the higher pH values may be the result of, not the cause of,
Cladophora growths) values are high (Prescott, 1951), such as are found
in Lake Ontario. The results of studies by Neil and Owen (1954) to
determine the limiting factors suggested that phosphorus, rather than
nitrogen, is the limiting nutrient.
Cladophora growth begins in early spring with a fringe-like growth
and develops rapidly into strands 15 inches or so in length by late June.
These strands at times break away from their substrate, drift up onto
the shore, decompose, and cause strong odors and an unsightly condition.
3-8
-------
During the early summer months at Lake Ontario bathing beaches*
it is a common occurrence to see no swimmers in the water and life--
guards raking and shoveling Cladophora mixed with dead fish, (the di
off of alewives begins in May and continues until late July), parti*
cularly in areas where artificial groins have trapped the algae and
dead fish by their interference with the littoral drift, such as ocC
at Webster Beach near Rochester. To say that it is an unsightly me*
that lakeshore property values are affected, and that recreation is
impaired, is indeed an understatement.
Fishing
Lake Ontario never has had a good commercial fishery. While tf
particularly in the years before 1930, were considered good, with af
annual production of approximately 5 million pounds, the annual pro1
tion has now dropped to less than 2 million pounds. The decline in,
commercial fishery is related to the decline of the desirable specif
such as lake trout and cisco, and is not indicative of the total f^
life contained within the lake, inasmuch as the numbers of certain f(
species of fish have increased, particularly the alewife, white pe^
and smelt.
Sea-lamprey predatism, which threatens the lake trout when H
fairly mature (about three years old), is a major factor in the dec
of lake trout. Lake Ontario was the first of the Great Lakes to be
3-9
-------
invaded by the sea lamprey. However, it is difficult to see how the
lamprey alone could account for the decline of the lake trout, inasmuch
as the lamprey has been present in the lake since before 1900 and the
major decline of lake trout began in 1930. (The first heavy growths of
Cladophora in the lake were first reported in 1932). Also significant
is the predatism of the increasing numbers of alewife and smelt, which
threatens the trout spawn. Interesting is the increasing number of
reports of a spring run of rainbow trout, which, unlike the lake trout,
is a stream spawner and thus may escape the early predatism by other
lake fish. The fact that Lake Ontario does not have a balanced fish
population or a significant commercial harvest, in effect, increases
the propagation of algae.
Alewives present a serious problem in Lake Ontario because they
apparently have a two-year life cycle, and in late May or June, when
the die-off is most severe, numerous windrows of dead fish are visible
throughout the lake. These fish eventually drift or are driven into
the littoral zone. Decomposition of these fish enriches the inshore
waters with large amounts of nutrients, notably phosphorus. This may
indirectly stimulate the heavy growths of Cladophora.
A suggested solution is that a commercial alewife fishery be
developed and that efforts be made to promote the growth of desirable
species of fish, possibly the rainbow trout or coho salmon. This would
3-10
-------
help to cut down on the number of alewives and smelt while increasing
the number of desirable species and, in effect, would remove phosphat
from the water mass by harvesting and by increased retention (storage
time in the phosphate cycle. It should be pointed out here that such
fish as coho salmon and rainbow trout need unpolluted streams for
spawning. If, for example, the number of alewives present in Lake
Ontario is proportional to the number in Lake Michigan, as reported bj
the Bureau of Commercial Fisheries, 150,000 pounds of phosphate could
be harvested each year without affecting the alewife population. This
would amount to less than a one percent removal of the gross input of
phosphate each year, but, if one assumes that during the month of June
input to the Ontario phosphate budget is reduced by 150,000 pounds
because of a reduction in die-off, the actual effect of this is much
greater, perhaps as much as 20 percent, particularly if the harvesting
was done in early spring. A/thorough study, however, should be made
before introducing any new species of fish into Lake Ontario so that
the long-term result is not merely the substitution of one problem
for another.
Trnphogenic Zone
The trophogenic zone is defined by Ruttner as "the superficial
layer of a lake in which organic production from mineral substances
3-11
-------
takes place on the basis of light energy". This zone has been further
defined as the layer that encompasses 99 percent of the incident light.
The thickness of the trophogenic zone in Lake Ontario was measured by a
submarine photometer* which consisted simply of an incident light
reference cell and a submergible cell that was lowered until it measured
a light value that was one percent of the value recorded by the reference
cell. Inasmuch as the length of daylight in the lake depths is inversely
proportional to the depth, and sampling was carried out throughout the
day, these data should be considered only fair.
Light penetration into lake water is an important physical factor
for plant life. If light penetration is low, it affects the whole
biology. The principal factors that affect the depth of penetration
are suspended plants and animals and suspended particulate material
such as clays, silts, and colloids.
Figures 3-8, 3-9, and 3-10 show the depth of the trophogenic zone
for the three cruises. In May (Cruise 102), Figure 3-8, the shallowest
penetration was recorded near the mouths of the major rivers, as one
would expect at this time of year. The shallow penetration (20 feet)
shown at the mouth of the Niagara River, as compared to the value
found off the Genesee and Oswego Rivers (50 feet), is probably due
to sampling locations and not to a significant difference in turbidity
3-12
-------
M
TROPHOGENIC ZONE
CRUISE 102
m1««t.
-------
b*
TROPHOGENIC ZONE
CRUISE 103
NOTE! Depth of light penetration in feet.
-------
2
§
i
V
o
ROPHOGENIC ZONE
CRUISE 104
-------
caused by river discharge. In May, the difference in depth of tropho-
genic zone depends principally on suspended silts and clays.
Figure 3-9 shows that the trophogenic zone during Cruise 103 was
generally shallower than during Cruise 102. The reason for this is
most likely due to an increase in suspended plankton and not to sus-
pended silts and clays. The area of shallow depths off the Oswego River
corresponds to the area in which a plankton bloom was reported during
July.
Figure 3-10 shows the trophogenic zone distribution for Cruise 104.
Immediately apparent are the greatly increased depths.* At this time
of year, the fall storms have not yet affected the lake,and the produc-
tion of plankton has lessened and/or spread out in depth.**
The difference in the general overall depth of the trophogenic zone
noted from one cruise to the next indicates a seasonal change in the
makeup of the trophogenic zone. In general, these data also agree with
water circulation of the lake during these periods. Implicit is the
danger of defining a typical physical characteristic such as this on
the basis of a few single season measurements.
Comparison of Figures 3-8, 3-9, and 3-10 with Figure 2-1, shows the
limited zone where light reaches the bottom.
**During this calm period in the fall, the lake is cooling; thus the
density of the epilimnion is changing and increasing in depth.
3-13
-------
Chapter 4
MICROBIOLOGY OF LAKE ONTARIO
Introduction
The microbiological study in the Lake Ontario Basin investigated
the parameters of total coliform and total plate counts. All of these
tests were conducted using the membrane filter technique. The total
coliform test is used as an index of all coliform organisms present and
does not differentiate those of fecal and non-fecal origin. The total
plate counts is a supplemental test which uses a nutrient media con-
ducive to the growth of bacteria, including those of natural waters and
:the intestines. Plate counts at 20°C (Figure 4-1 and 4-2) are considered
^to give an estimate of heterotrophic bacteria in natural waters. Plate
counts at 35°C (Figures 4-3 and 4-4) are considered indicative of hetero-
trophic organisms of pollutional origin.
In the eastern end of the lake, total plate counts and total coliform
counts are low, except during Cruise 103, when a slight increase was
noted in total coliform. Total coliform counts in the western part of
the lake were low. Many stations showed no coliforms; a few, however,
were in the 500/100 milliliters range, with the high counts in the Niagara
River and Toronto area.
U-i
-------
HAMILTON
NOTE'. Total count/iOOml. at 20°C.
TOTAL PLATE COUNT! 2CPC.
CRUISE 102
MAY, 1965
-------
10
t
HAMILTON
NOTE! Total caunt/IOOml. at 20-C.
TOTAL PLATE COUNT! 20° C.
CRUISE 103
JULY-AUGUST, ises
-------
10 0 10 20 SOmi
HAMILTON
NOTE! Total count/IOOml. at 35°C.
TOTAL PLATE COUNT! 35° C.
CRUISE 102
MAY, 1965
-------
10
o
55
m
44,000
I'000 16,000
NOTE! Total count/ 100ml. at 35° C.
TOTAL PLATE COUNT! 35° C.
CRUISE 103
JULY-AUGUST, 1965
-------
The central area of the lake has the lowest bacteria counts of all.
Part of the central area did have higher counts of total coliforms and
total bacteria. Of these low counts, the non-pollutional plate counts
were in the vicinity of Rochester, and a gradational distribution of
these higher counts towards the northeast was noted. Total coliform
counts were low, with some stations recording zero during Cruise 102.
The higher of these low counts was recorded in the southern part. At
station 23, the total coliform counts were near 500 coliforms/100 milli-
liters.
The eastern end of the lake showed higher bacterial values, especi-
ally near the Oswego River. Total plate counts indicated a greater
amount of 20°C (non-pollutional) organisms than the 35°C (pollutional)
organisms. Total coliform counts were low.
The role that bacteria play in the lake environment is important.
However, it is an extremely complex subject of which little is known.
We do know that certain types of bacteria reduce sulphate and fix
nitrogen, and that some secrete such compounds as calcium carbonate
and ferric hydroxide, but knowledge of the chemistry of this bacterial
action is lacking. Bacteria, in general, through metabolic processes,
break down substances into simpler forms which, in effect, make them
more acceptable to the algae.
-------
Chapter 5
CHEMISTRY
Introduction
The chemistry of the lake waters and the streams entering the lake
is most important, for it is the mineral substances dissolved in these
waters that govern the type and quantity of the animal and human
communities that establish themselves within the lake basin. How fit
these waters are for human consumption, fish life, recreation, industry
are all factors that govern the long-term productivity of this region.
The chemistry of the lake waters is constantly changing, adjusting
to biological, physical, and chemical demands or changes. Thus, chemical
parameters in themselves are not as directly meaningful as we would desire
them to be in evaluating a large lake. Many elements and/or compounds
are part of a biogeochemical system. Consequently, a measurement of a
particular element or compound represents only what is existing in
that part or phase of the system; it does not represent the quantity or
speed of an element or compound moving through the system. For example,
sediments may be able to supply from storage certain substances to the
water mass as rapidly as the biota may use them, and, as a consequence,
the concentration of that substance in the water mass would remain constant.
5-1
-------
In a lake, the concept of availability to a biogeochemical system as
opposed to concentration of a dissolved substance per se is important;
since the lakes have a stability (long retention time) unlike streams,
where the chemical part of these biogeochemical systems can, and in matf
cases do, reach and remain at equilibrium and may or may not remain in
that state.
The most immediate problem, however, is the control of algae. Th*
implication is that any chemical substance used by the algae is part of
a system or cycle and that availability or lack, rather than concentra^
is the measure of control.
X
Nitrogen
Nitrogen occurs in Lake Ontario in five major forms: atmospheric
nitrogen (N2), ammonia, (NH^1), nitrite (N02~^)» nitrate (N03"^), and
as organic nitrogen compounds. Nitrogen is a fundamental element in art
organism's metabolism, which is the synthesis and maintenance of proto-
plasm.
"Nitrogen chemistry is controlled largely by biochemical reaction5
in natural waters". (Lee & Hoadly, 1967, p. 327). The oxidation and
reduction of nitrogen compounds (nitrogen cycle) are principally the
result of enzymatic processes.
5-2
-------
A graphic comparison of (trilinear diagrams) the relative amounts
of nitrate nitrogen, ammonia nitrogen, and organic nitrogen, by percent
weight, in Lake Ontario, using data from FWPCA cruises 102 (May 1965),
103 (July 1965), and 104 (September 1965), Figures 5-.1, 5-2, and 5-3
respectively, shows that in the spring the surface layer is rich in
nitrate\ but by July an increase in organic nitrogen compounds occurs
with a related decrease in nitrate and ammonia. In the fall, the
amount of organic nitrogen in the surface layer lessens and a corres-
ponding increase in nitrate and ammonia occurs.
Vertically, during the spring (FWPCA 102), the amount of organic
nitrogen and nitrate followed no specific pattern, which probably is a
reflection of changing lake conditions. Generally, the relation between
organic nitrogen and nitrate nitrogen was an inverse one. Ammonia
nitrogen concentrations appeared to be random.
Vertically, during the summer (FWPCA 103), a maximum of organic
nitrogen was observed just above the thermocline. Nitrate nitrogen
concentrations were observed to increase from the surface downward.
The nitrate maximum was usually observed at approximately 150 meters deep.
During the spring cruise, photosynthesis was already occurring and
is reflected in Figure 5-1. Thus, some nitrate, from supposed
higher winter concentrations, has been converted into organic
nitrogen.
5-3
-------
N03 (N)
NOTE: By percent of total Nitrogen
50
,. V\/V\A/V\A/\/\AA AA A A A A
/V\AA/ " V ~^-
NH3 (N)
Organic (N)
RELATION OF NITRATES, AMMONIA AND ORGANIC NITROGEN
IN
LAKE ONTARIO SURFACE WATER
CRUISE 102
MAY, 1965
-------
N03 (N)
NOTE: By percent of total Nitrogen
/\/\/\/\/\/\r\/\/\/\/\/\/T/
A/WVVW
NH3 (N)
50 Organic (N)
RELATION OF NITRATES, AMMONIA AND ORGANIC NITROGEN
IN
LAKE ONTARIO SURFACE WATER
CRUISE 103
JULY-AUGUST, 1965
-------
NOo (N)
NOTE: By percent of total Nitrogen
/WVAAAA
50
NH3 (N)
50
50 Organic (N)
RELATION OF NITRATES, AMMONIA AND ORGANIC NITROGEN
IN
LAKE ONTARIO SURFACE WATER
CRUISE 104
-------
However, this observation could have been affected by sampling procedures.
The ammonia nitrogen maximum usually was located just above the thermo-
cline.
Vertically, during the fall (FWPCA 104), an overall increase in
nitrate nitrogen concentrations was observed, maximum again occurring
at the 150 meter depth. A corresponding decrease in organic nitrogen
was observed, maximum again occurring above the thermocline. Ammonia
nitrogen varied, but the maximum normally occurring near the thermocline.
Ammonia Nitrogen
Ammonia nitrogen is formed by the decomposition of plant and
animal matter. It is oxidized to nitrate in oxygen-containing waters
by microorganisms.
Ammonia is relatively unstable in the water of Lake Ontario. It is
first changed to nitrite and then nitrate. Figures 5-4, 5-5, and 5-6
show the distribution of the ammonia in Lake Ontario surface water for
FWPCA cruises 102, 103, and 104 respectively. Obviously, the higher
concentrations of ammonia observed were in areas of metro-industrial
development and stream discharges. The weighted averages (weighted on
basis of volume of water mass) for ammonia for FWPCA cruises 102, 103,
and 104, were 0.66 mg/1 N, 0.04 mg/1 N, and 0.07 mg/1 N.
-------
o
X
!O O 10 2O JO
SURFACE DISTRIBUTION OF
AMMONIA
CRUISE 102
-------
HAMILTON
NOTE. Ammonia in mg./l. (N)
SURFACE DISTRIBUTION OF
AMMONIA
CRUISE 103
JULY-AUGUST, 1965
-------
a
rfi
u
NOTE! Ammonia jn mg./l.(N)
HAMILTON
YORK SURFACE DISTRIBUTION OF
AMMONIA
CRUISE 104
-------
Nitrite
Nitrite, like ammonia, is an intermediate product of the nitrogen
cycle and is the result of decomposition; on further oxidation, nitrite
is converted to nitrate. In northern fresh water lakes, the regenera-
tion processes of nitrogen apparently run to completion, and inorganic
nitrogen is present, principally as nitrate. Consequently, nitrite is
transitory in the lake environment. The water samples collected by the
FWPCA were not analyzed for nitrite nitrogen.
Nitrate Nitrogen
Nitrate is the most important form of inorganic nitrogen found in
natural waters. It is the form of nitrogen which is required by most
phytoplankton, and is formed by the oxidation of organic material.
The data collected by the FWPCA in 1965 (Figures 5-7. 5-8. and 5-9,
cruises 102, 103, and 104, respective!y)show that the highest concentra-
tions of nitrate in the surface water of Lake Ontario were observed
in the inshore areas, particularly in areas of influent streams and metro-
industrial centers. The weighted averages for nitrate concentrations
were 0.34 mg/1 N (FWPCA Cruise 102), 0.31 mg/1 N (FWPCA Cruise 103), and
0.41 Mg/1 N (FWPCA Cruise 104).
5-5
-------
n
c
—
--
SURFACE DISTRIBUTION OF
NITRATE
CRUISE 102
MAY, 1965
NOTE! Nitrate in mg./l.
-------
10
NOTE.
Result* in mg./l.
HAMILTON
SURFACE DISTRIBUTION OF
NITRATES (NOS) IN
LAKE ONTARIO
JULY 1965 (CRUISE 103)
-------
1
r
0 10 2050"l
HAMILTON
SURFACE DISTRIBUTION OF
NITRATE
CRUISE 104
SEPTEMBER-OCTOBER, 1965
NOTE. Nitrate in mg./l. (N)
-------
Organic Nitrogen
Organic nitrogen is the nitrogen that is bound up in organic
materials, ranging from complex proteins to a simple substance, such
as urea. It consists of two fractions: the dissolved organic one
and the particulate one, which is the fraction bound up in the animate
and inanimate particles in suspension. On decomposition, the organic
nitrogen compounds are oxidized into inorganic nitrate nitrogen. The
concentrations of organic nitrogen also give some indication of the
lake's primary production. Figures 5-10, 5-11, and 5-12 show the
distribution of organic nitrogen in Lake Ontario from FWPCA Cruises
102, 103, and 104, respectively. High organic nitrogen values are
generally found in the inshore area. Correspondingly, the inshore
area is also where the greatest biological activity occurs. The highest
values were observed in the area of metro-industrial development and
major stream mouths.
The weighted averages for organic nitrogen, FWPCA Cruises 102, 103,
and 104 were 0.20 mg/lN, 0.21 mg/lN, and 0.20 mg/lN, respectively.
Inasmuch as most of the organic nitrogen is found in the epilimnion, the
use of weighted averages gives greater weight to samples taken from
deeper depths (greater water mass and lower concentrations). This is the
reason for the apparent high organic nitrogen content of the lake during
5-6
-------
33
m
CD
10 0 IO 20 SO"*
HAMILTON
SURFACE DISTRIBUTION OF
ORGANIC NITROGEN
CRUISE 102
MAY, 1965
NOTE! Organic Nitrogen in mg./l. (N)
-------
SURFACE DISTRIBUTION OF
ORGANIC NITROGEN
CRUISE 103
JULY-AUGUST ,1965
NOTE. Organic Nitrogen in mg./l.(N)
-------
x
m
en
HAMILTON
SURFACE DISTRIBUTION OF
ORGANIC NITROGEN
CRUISE 104
SEPTEMBER-OCTOBER, 1965
. / V -
-------
the spring cruise, for at this time the lake water was still in a state
of flux. These figures do represent, however, the amount of organic
nitrogen occurring in the water mass. In comparison, the arithmetic
averages for organic nitrogen in the lake for FWPCA Cruises 102, 103,
and 104 were 0.26 mg/lN, 0.25 mg/lN, and 0.23 mg/lN, respectively.
General Discussion
The problem of eutrophication is one of the chief concerns about
Lake Ontario. The eutrophication of a lake is the buildup of nutrients
in the lake's environment caused by an interplay of erosional materials
and numerous biological, chemical, and physical processes. As the
buildup of nutrients progresses, the lake acquires the capacity to
progressively produce a larger biomass. One way that the eutrophfcation
process could be slowed down is simply to determine which of the major
nutrients in the water mass was deficient relative to the others and
then to further control the input to the lake of the deficient (limiting)
nutrient.
The protoplasm of algae (Fleming, 1940) contains nitrogen and
phosphorus in a mean ratio of 15:1. Sawyer suggested further that one
could determine if nitrogen or phosphorus was the limiting nutrient by
determining what the ratio of nitrate nitrogen to phosphorus was in a
lake. In lakes where the ratio of N:P in the water mass was less than
5-7
-------
15:1, the production of algae would be limited by the availability of
nitrogen. Conversely, where the N:P ratios were higher than 15:1,
phosphorus would be the limiting nutrient. N:P ratios must, however»
be used with caution. The biomass can alter their relative demands
for nitrogen and phosphorus in response to changes in the relative
supply of these two nutrients. A change in the relative uptake of
nitrogen and phosphorus by the biomass would also affect the N:P ratio*
Fresh water algae grown under a phosphorus deficient condition can
increase their relative demand for nitrogen and,conversely, algae gro*"1
under nitrogen deficient conditions lowered their relative demand for
nitrogen (Ketchum & Redfield, 1949). In Lake Ontario surface waters*
the N:P ratios in 1965 were 23:1 in the spring (FWPCA Cruise 102),
18:1 in the summer (FWPCA Cruise 103), and 26:1 in the fall (FWPCA
Cruise 104). While these nitrogen to phosphate ratios must be inter-
preted with caution, as outlined previously, the suggestion is that
phosphorus rather than nitrogen is the major limiting nutrient in Lake
Ontario.
Phosphorus (Phosphate)
Phosphorus as phosphate is part of a complex biogeochemical cyde
in the lake environment, the details of which are not clearly understn°°
5-8
-------
Soluble phosphate is the phosphate measured after filtering through a
45 micron filter. Total phosphate is all the phosphate.
Soluble Phosphate
Figure 5-T3 (Cruise 102) shows the distribution of soluble phosphate
in the surface layer of the lake. Of particular note are the high values
of soluble phosphate found in the western end of the lake and off the
Oswego River. The distribution is similar to the distribution patterns
found for pH, temperature, and dissolved oxygen, which is as it should
be inasmuch as all of these parameters are inter-related to a certain
extent and influence phosphate equilibria. The shape of the high soluble
phosphate area off Oswego is probably due to change in circulation
(See Figure 5-18) which occurred while sampling this area.
Figure 5-14 shows the areal surface distribution of soluble phos-
phate observed during Cruise 103. High values of phosphate are found
in the vicinity of river mouths. It is difficult to say where the
pool of water in the vicinity of Main Duck Island, with its high phosphate
values, formed; it may have broken away from the Oswego River flow, or
its source may have been the Black River.
Figure 5-15 shows the distribution of soluble phosphate in the
lake's surface layer observed during Cruise 104. An increase in soluble
phosphate was observed during this period, particularly in the eastern
5-9
-------
10
o
33
04
HAMILTON
DISTRIBUTION OF
SOLUBLE PHOSPHATE
CRUISE 102
HOTE.'. So\ubV«
-------
10 0 10 20 S0mi
HAMILTON
DISTRIBUTION OF
SOLUBLE PHOSPHATE
CRUISE 103
NOTE.Solublt Photphott in microgromt/ liter
-------
10
m
•
3
HAMILTON
DISTRIBUTION OF
SOLUBLE PHOSPHATE
CRUISE 104
NOTE.'.
-------
end of the lake. Once again, the surface waters near the mouth of the
Niagara River are rich in phosphate. Pools of phosphate concentrations
are scattered throughout the rest of the lake. A large area of soluble
phosphate appears to originate at the mouth of the Oswego River, decreas-
ing in concentration as it extends into the lake. The reason for the
overall increase in soluble phosphate at this time is unknown. Inasmuch
as the source of the phosphate appears to be from river inflow, it may
be related to a reduction in phosphate uptake by biota.
Total Phosphate
The total phosphate content of a water sample includes all the
soluble orthophosphate, polyphosphates, and insoluble phosphates. No
samples from Cruise 102 were analyzed for total phosphate.
Figure 5-16 indicates the surface distribution of total phosphate
observed during Cruise 103. Total phosphate values of .10 mg/1 P04"3
(.033 mg/1 P) were found off the Rochester embayment; these were the
highest recorded values during this study. Distinct distribution patterns
occur in the vicinity of the Toronto-Hamilton-Niagara River area, and
the Oswego River.
The results of Cruise 104, Figure 5-17, show a rather contorted
distribution of total phosphate, much like the data for soluble phosphate
(Figure 5-15). The concentrations of total phosphate near the mouth
of the Niagara River have increased since Cruise 103, while the other
major streams show a decrease in total phosphate concentration.
5-10
-------
10
5
m
at
HAMILTON
TOTAL PHOSPHATE
LAKE ONTARIO
CRUISE 103
NOTE. Totol Phosphate in microqram«/liter
-------
HAMILTON
TOTAL PHOSPHATE
LAKE ONTARIO
CRUISE 104
NOTE'. Total Phosphate in micrograms/lit«r.
-------
In summary, phosphates in the lake's water-mass are transitory in
nature, due to the biogeochemical cycling of phosphate, and the areal
extent of input by streams and the metropolitan-industrial complexes
is variable, consequently, it would seem that the reference for phosphate
levels in maintaining water-quality control should be located at the
point source of input to the lake, rather than establishing a phosphate
water-quality criteria for the water mass as a whole. What is impor-
tant is the amount and type of phosphate available to the biota and
not just what is in solution (low phosphate levels can be caused by
the biota taking up the phosphate).
General Discussion
If one considers how long the Great Lakes have been in existence,
the question is why haven't they become more contaminated? The
answer to this question is that a systematic depoisoning of the hydro-
sphere has occurred in the past and is occurring now. Without this
depoisoning process a number of biologically damaging elements would
have caused serious poisoning of the lakes naturally in the past.
What then is this process or group of processes as regards to phos-
phate?
The phosphate cycle is part of a very complex biogeochemical
system. However, some generalizations can be made. The same
mechanisms that account for the removal of phosphate and various
other compounds from the water mass are also responsible for the
5-11
-------
build-up of the chemistry of the total lake environment^. For example,
soluble phosphate in the river waters is carried into the lake where
the biota, in effect, filter some of it from the water mass and
deposit it, through various processes, on the bottom.
Colloids in the lake waters are also responsible for the removal
of phosphate ions from the hydrosphere. An important property of
colloidal particles is their ability to bind and concentrate certain
substances through physical and chemical adsorption. Both types of
adsorption act together and all gradations between extremes exist.
n
Clay particles display a marked sorptive capacity for phosphate
ions either by acceptance into the crystal lattice or by adsorption.
If one considers the number of clay and colloidal particles that are
present in the lake water, the amount of uptake of phosphate and other
ions by these particles must be great.
The iron cycle also has an effect on the phosphate cycle. Just
as waste treatment plants use ferric hydroxide to adsorb and precipi-
tate phosphate ions, this occurs naturally in the lake water. Iron
is generally carried in surface waters as ferric oxide hydrosol stabi-
lized by organic colloids. The compound of iron that is precipitated,
Chemical buildup here includes materials that are stored in the
biota and sediments, hence not necessarily in solution.
p
Clays are found in the collodial state as well as suspended,
and their importance in lake chemistry is emphasized here.
5-12
-------
while also a function of the pH, is principally a function of the
oxidation reduction potential (Garrels, 1950). At the lowest, only
ferrous sulphide will form; at slightly higher potential ferrous
carbonate is precipitated. Under fully oxidizing conditions, such as
found in Lake Ontario, ferric hydroxide and ferric phosphate are
formed. The ferric hydroxide precipitate carries phosphate ions with
it as it drifts to the bottom.
Another factor in the phosphate cycle as regards Lake Ontario
is that phosphate (Sutherland, 1966) appears to be in equilibrium
with respect to the hydroxyapatite (Ca-|0(P04)° (°H2^ systemi therefore,
excess phosphate ions tend to precipitate with other metallic ions
and be removed in order to maintain equilibrium in the water mass.
The lake's biogeochemical systems all tend to reach an inter-
equilibrium, which explains why, up to a point, nature appears to be
most forgiving of man's activities. However, while these phosphate
removal mechanisms are a good thing, there is the danger that if any
one factor is changed, the whole equilibrium shifts. Several examples
of this are as follows: In late summer when the die-off of algae and
other organisms begin to put a load on the oxygen in the hypolimnion,
the oxidized microzone on the bottom, which is rich in ferric hydroxide
and ferric phosphate, may be reduced, the associated organic material
being a good reducing agent; the ferric ion changes to the ferrous
5-13
-------
state and the result is that (if a disequilibrium of phosphate demand
exists in the water mass) phosphate ions are again released into solu-
tion, and increase in sodium sulphate (at lower pH) or calcium ions
also upsets the phosphate equilibrium by causing more phosphate to move
into solution. Calcium is in saturation as regards Lake Ontario.
Sawyer, in his studies, found that phosphate concentrations of
.010 mg/1 P would cause algae blooms. In reality, his results only
apply to the specific lakes that he studied. Inasmuch as nutrient
uptake by the biota is a function of the concentrations maintained at
the cellwater interface, it is suspected that in the case of lakes
with good circulation and large nutrient reserves, such as Lake
Ontario, the concentration of phosphate needed to cause algal blooms
is less than Sawyer's results show.
Bass Becking and Kaplan, 1960, in a study of the limits of pH
and Eh (oxidation-reduction potential) in the natural environment,
make the generalization that oligotrophic waters have pH values on the
acid side and eutrophic waters tend to be alkaline. Of the Great Lakes,
only Lake Superior would fit the definition for an oligotrophic lake on
the basis of pH. This does not mean that all of the Great Lakes except
Superior are eutrophic, but it does suggest that there is a natural
tendency for them to become so as regards availability of nutrients.
This, of course, is due to the areal geology of the region with
its numerous limestone formations. Since 1900, a large increase of
5-lU
-------
sulphate ions in the Great Lakes has occurred, the effect of which,
as mentioned previously, may be to make more phosphate available to
any biological system. Also, since 1900, a change in the fish population
has occurred. A good example of this is the increase in the number of
alewives, whose life cycle appears to be two years; thus, where phosphate
may have been stored in a large lake trout for several years, in the
case of the alewives, it is recycled every two years. This extra shot
of phosphate1, due to the die-off of alewives, comes at the worst
possible time—early summer. Another factor is that, unlike other fish,
the alewife is not now harvested. Assuming that the Lake Ontario ale-
wife population is proportional to the Lake Michigan population (U.S.
Bureau of Commercial Fisheries, 1966), approximately 5.0 x 106 Ibs. con-
taining 150,000 Ibs. of phosphate could be harvested each year without
affecting the alewife population. The effect of reducing phosphate in
the lake by harvesting alewives would be felt during the start of the
growing season.
Phosphate Removal at Treatment Plants
No one ideal situation exists for reducing the algal growths in
Lake Ontario, and several methods of attack on the problem must be used.
However, a program of phosphate control, including maximum removal of
' Bacterial working of the dead Jish make the phosphate available to
the algae in a readily assimilated form.
5-15
-------
phosphates at treatment plants, may, In the case of Lake Ontario, bring
the most rewarding results. The reason for this is that this lake has
a tremendous oxygen reserve in the hypolimnion, having a small surface
area in relation to volume. It has been known for some time that a
self-regulating system exists in the phosphate cycle between the water
mass and the lake muds. The oxidized sedimentary microzone which
develops at the mud -water interface is rich in ferric hydroxide and
ferric phosphate. This microzone forms a chemical barrier that keeps
phosphate ions from the reduced sedimentary layer beneath it from going
into solution and, also, assimilates material falling to the bottom.
Thus, as long as the oxidized microzone exists, phosphate raining onto
the bottom from various biogeochemical systems remains tied up. The
longer this microzone remains in the oxidized state, the more phosphate
will be removed from the water mass.
In Lake Ontario, the oxidized microzone may exist most of the year,
possibly all year. If this is the case, reduction of phosphate input
to the lake could bring almost immediate results. In shallower lakes,
because of their physical characteristics, the oxidized microzone which
develops during the winter months probably disappears in early summer;
this causes a recycling of phosphate, which will supply phosphate ions
to the water mass for some years after the phosphate inputs are reduced.
5-16
-------
Hydrogen-Ion Concentration (pH)
The hydrogen-ion concentration of the lake waters is of great
significance for it represents the overall balance of a series of chert'
ical and biological equilibria existing in the lake waters. In disti
water at 20°C, the hydrogen ion concentration is 10"' moles/liter, or»
using the negative logarithm to simplify matters, the pH is 7. If the
concentration is greater than that of distilled water, the solution
is considered acid (pH less 7), and, in the opposite case, alkaline.
The pH of most natural waters is controlled by the buffer systems
CaCCL-C^-HpO; a saturated solution of carbon dioxide at its partial
pressure in the atmosphere has a pH of 5.2, and a solution of
calcite (CaC^) in air-saturated water has a pH near 8, (Mason, 1952).
Solutions of phosphates, silicates, borates and fluorides also
affect the pH of the waters, but to a lesser extent than the COg-CaCX^
system. Important here, as regards nutrients for development of an
abundant biota, is that most calcite minerals are not pure and usually
they contain various amounts of the mineral apatite (CagfPO^F;
thus, natural solutions of calcite also contain apatite. Rocks con-
taining large amounts of apatite are called phosphate rock and are
used for fertilizer. This helps to explain why lakes that have high
p'H values are usually productive, whereas so-called acidic lakes are
not usually productive. Bass Beckling (I960) classifies lakes on the
5-17
-------
basis of pH as being either oligotrophic or eutrophic, eutrophic lakes
being those with a pH above 7.
The pH of a solution also is important in regulating the iron cycle.
The importance of this is that phosphate ions can be either removed or
released to or from solution in conjunction with the iron cycle.
Figure 5-18 shows the distribution of surface pH observed during
Cruise 102. The pattern observed in the western end of the lake is
much like the patterns obtained for dissolved oxygen, temperature,
soluble phosphate, and circulation during this cruise. In the eastern
end of the lake the pH was lower than in the western end, and, unlike
the western end, the highest values are found toward mid-lake. The reason
for this apparent difference in areal distribution of pH at either end
of the lake is that a wind shift occurred. During sampling in the
eastern end, the winds were, at times, out of the northeast and during
sampling in the western end they were from the southwest.
Several separate pools of water are discernible in the eastern and
central parts of the lake. These pools were probably formed as one
water mass in the area behind the Duck Islands and were pushed out into
the lake, mixing with deeper waters which have a lower pH. Originally,
the distribution of pH was probably much like that of the western end,
with higher pH values inshore. In a change of regime, however, these
5-18
-------
-N-
HiMILTON
Wind direction during
Mmpllng of fhit ttetloit.
if**?,
Wind direction tfurhtg
tampllnj of thl* i«e*lon
HYDROGEN ION (pH)
CONCENTRATION
CRUISE 102
\t\ c\rcu\aV\on.
-------
waters would be the first to lose their identity because of mixing due
to the increased turbulence inshore. This change in the wind regime
is not as readily apparent in the distribution of other chemical para-
meters, inasmuch as the higher pH values in the surface waters may
have been due to biological activity at the surface and were readily
changed by mixing.
Figure 5-19 shows the distribution of pH observed during Cruise
103. The surface of the lake was quite calm during this period and
the circulation was sluggish. Notable is the overall increase in
PH; pH values of 9 and above are common and occur generally away from
shore. The increase in observed pH is probably the result of bio-
logical activity, heating, and quiescent lake conditions (little
mixing). This increase in pH may indirectly be related to the
availability of nutrients.
Figure 5-20 shows the distribution of pH observed during Cruise
104. Here the values of pH have dropped since the July-August (103)
cruise. The pH distribution during this period follows the observed
circulation and surface temperatures of the lake.
Lake Ontario surface waters are near saturation in calcium
carbonate; pH values higher than 8 are probably due to lake warming
and biological activity and hence are related to, in part, the avail-
5-19
-------
m
I
•\
10 O 10 ZO 50"ii
HAMILTON
HYDROGEN ION (pH)
CONCENTRATION
CRUISE IO3
-------
rn
rv>
O
10 O 10 20 SO
HAMILTON
HYDROGEN ION (pH)
CONCENTRATION
CRUISE 104
-------
ability of nutrients.
In conclusion, pH is representative of the 'total' lake environ-
ment.
Dissolved Oxygen
Oxygen dissolved in water is necessary to support life and to
oxidize organic material. The amount of dissolved oxygen also plays
an important role in the regulation of the iron cycle and, thus,
indirectly in the amount of phosphate that is either removed or put
into solution (see phosphates).
Figure 5-21 shows the percent of oxygen saturation observed
during Cruise 102. At this time the lake water was still isothermal
and was well mixed. Nowhere were dissolved oxygen values below 100
percent saturation observed. The high values above 100 are most
likely due to photosynthesis occurring because of a 'spring pulse1
of phytoplankton.
These areas of supersaturation correspond to the shallower areas
of the lake. Of particular note are the values occurring in the
Toronto-Hamilton area.
Figure 5-22 indicates the percent of oxygen saturation (Cruise
1'02) found near the bottom of the lake. At no place were values of
5-20
-------
DISSOLVED OXYGEN
% SATURATION
AT SURFACE
CRUISE 102
-------
(—
8
X
m
v
ro
10 0 10 ZO SO
HAMILTON
DISSOLVED OXYGEN
% SATURATION
NEAR BOTTOM
CRUISE 102
-------
less than 98 percent of dissolved oxygen saturation observed.
Figure 5-23 gives the results of Cruise 103. Once again, the
dissolved oxygen concentrations are above or very near saturation
values. The effect of what may be nutrient input by the major cities
can be seen in the higher values of dissolved oxygen caused by photo-
synthesis found in their vicinity. Surprisingly enough, no effect
of the Niagara River was discernible.
Figure 5-24 shows the distribution of dissolved oxygen concen-
trations in percent of saturation in the bottom waters for Cruise
103. One can readily see that some consumption of oxygen has
occurred in that levels slightly below 80 percent of saturation were
observed in the lake proper and a low value of 70 percent saturation
was observed in the bay area behind Duck Island. During the latter
part of July 1965, samples of the lake sediments were taken. All of
the sediment samples from the deep areas of the lake were observed
to have a red, oxidized microzone approximately 1/4 inch thick,
indicating that oxidizing conditions existed at the mud-water inter-
face. How long this oxidized microzone exists is not known, but it
is suspected that it remains all year long. If this is true much
of the phosphate that goes out of solution in conjunction with the
iron may never get back into solution (see phosphate discussion).
5-21
-------
10 0 10 20 30"ii
HAMILTON
DISSOLVED OXYGEN
% SATURATION
AT SURFACE
CRUISE 103
-------
V
HAMILTON
DISSOLVED OXYGEN
PERCENT SATURATION
NEAR BOTTOM CRUJSE 103
-------
Figure 5-25 shows the distribution of dissolved oxygen in percent
of saturation during Cruise 104. The amount of dissolved oxygen has
increased in the surface waters from the previous cruise. Distinct,
individual, chemically identifiable masses of lake water seem to
exist. Figure 5-26 shows the percent of dissolved oxygen observed in
the bottom waters during this same cruise. Values slightly below
70 percent saturation occur off the Toronto, the Niagara River,
Rochester, and Oswego. Scotch Bonnet Shoal and the ridge separating
the two basins are marked off by a value of 90 percent.
These oxygen data suggest that no zones of serious oxygen
depletion occur in the main part of the lake; therefore, on the
basis of these data the lake is considered to be oligothrophic.
The reason why no significant oxygen depletion occurs is that 85
percent of the lake's water mass is below the thermocline, so a
large reserve of oxygen is available during the period of stratifi-
cation.
Chlorides
It is not surprising that Lake Ontario, being the downstream
lake, has the highest chloride levels of all the Great Lakes. The
chloride ion is considered a good tracer element because most of its
compounds are soluble. The principal source of chloride in the
5-22
-------
n
u>
10 0 10 2O 30mi
HAMILTON
DISSOLVED OXYGEN
% SATURATION
AT SURFACE
CRUISE 104
-------
o
c
HAMILTON
DISSOLVED OXYGEN
PERCENT SATURATION
NEAR BOTTOM CRUISE 104
-------
Great Lakes is industrial and municipal pollution. Since the 1900's
a steady increase in chloride content has been observed. The
Practice of spreading salt on roads in winter to melt the snow
has also increased in recent years, and this salt ultimately reaches
the lake waters.
Figure 5-27 indicates the surface distribution of chloride
ion observed during Cruise 102. The pattern is quite simple; the
inshore waters have the highest concentrations and a large pool of
24 ppm water is found in the west-central part of the lake. Some
evidence of an effect from the Niagara and Genesee Rivers can be
seen.
Figure 5-28 shows the chloride ion distribution observed
during Cruise 103. The effect of both the Toronto area and the
Niagara River can readily be seen. The effect of the Genesee
River is not apparent. The area of high cloride concentration is
the same as that where the lowest light penetration was observed
during this cruise.
Figure 5-29 shows the chloride ion distribution observed
during Cruise 104. Again, areas of high chloride concentration are
found in the inshore waters near the Toronto-Hamilton-Niagara River
area. The highest concentration of chloride occurred in Mexico Bay
5-23
-------
c
m
i
ISJ
10 0 10 20 SO
HAMILTON
NOTE. CWo»\d* \n
DISTRIBUTION OF
CHLORIDES
CRUISE 1O2
-------
«.«
-N-
s
3D
m
10 0 10 20 JO
HAMILTON
DISTRIBUTION OF
SURFACE CHLORIDES
CRUISE 103
NOTE'. Chloridt in mg./l.
-------
1C
c
TO
m
5
'I
HAMILTON
NOTE. Chlorite m mq./ V.
DISTRIBUTION OF
CHLORIDES
CRUISE 104
-------
near Oswego. The source of this high concentration is probably the
Oswego River, which drains an area in which many rock horizons con-
tain salt. The pool of high chloride concentration observed during
Cruise 103 is still seen to exist. In the area of Scotch Bonnet
Shoal, an area of 26 mg/1 chloride water was observed.
While the concentrations of chloride ion measured during this
study only ranged from 22 to 27 mg/1 in the deep waters of the lake,
a pattern in the distribution of these values was observed and the
sources of the chloride can at times be identified.
Silicon
Silicon, one of the most abundant elements in the earth's
crust, is never found as the element. It occurs in the oxidized
state in true solution, as colloidal silica and as sestonic mineral
particles. The principal natural source of silica in Lake Ontario
is probably the clay minerals (the alumino-silicates) and dead diatom
skeletons. The solubility of the silicates is dependent upon the
pH; the higher the pH the greater the solubility. While the silicates
are not a constituent of the protoplasm, they form the skeletal material
for diatoms. A value below 0.5 mg/1 is considered limiting for
several species of diatoms. Dissolved silica values in Lake
Ontario waters are well below the maximum standard for most water
5-2*4
-------
uses with the exception of water used in boilers.
Dissolved silica values (reported as 8102) for Lake Ontario were
the highest during Cruise 102 (May 1965), Figure 5-30. The highest
values were generally found at the mid-lake stations and the lowest
values near the river mouths. Silica concentrations for this cruise
agree well with biological findings. It was during this cruise that
the highest diatom populations were observed.
Data from Cruise 103 (July and August 1965), Figure 5-31 shows
a marked reduction in the amount of dissolved silica in the surface
waters, suggesting that it was taken up by the diatom population
during the late spring and that an apparent die-off occurred by the
time of Cruise 103. To a certain extent, this agrees with the
biological data which shows a reduction in diatom population from
the previous cruise (102).
Data from Cruise 104 (September-October 1965) Figure 5-32,
shows that the values of dissolved silica levels have tended to
become more evenly distributed.
The obvious question is, where did the large amount of dis-
solved silica in the spring months come from? That it didn't come
from the rivers is apparent in Figures 5-30, 5-31. and 5-32, One
likely conclusion is that the silica was recycled from bottom
5-25
-------
I
en
c
m
w
o
10 0 10 2O 30
-------
a
m
HAMILTON
NOTE.'.
SURFACE DISTRIBUTION
OF Si02
CRUISE 103
-------
o<
10 0 10 ZO SO
HAMILTON
SURFACE DISTRIBUTION
OF Si02
CRUISE 104
NOTE! SiO? In mq. / I.
-------
material, perhaps from diatom skeletal material. Although no winter
data was obtained that would either support or disapprove this con-
clusion, this process has been observed by other researchers.
Sodium
Sodium is a very active metal and, like silica, is never found
free in nature. It is one of the most abundant cations found in lake
waters because nearly all sodium compounds are soluble. The high
sodium content of the oceans also demonstrates the tendency of this
element to remain in solution once it has been dissolved.
In Lake Ontario no significant distribution or range of sodium
concentrations was observed. This is not too surprising when again
we consider the solubility and the lack of an important chemical
or biological system that would remove it from solution (Sodium
in water in some circumstances does participate in base exchange
reactions whereby sodium replaces cations in clay minerals. What
importance this has in Lake Ontario is at present difficult to say,
but the very even distribution of sodium in these waters suggests it
is not of great importance). The principal natural source of sodium
in Lake Ontario waters is probably the sedimentary rocks in the Great
Lakes Basin inasmuch as calcium is the dominant cation by a factor of
about 4.
5-26
-------
Sodium concentrations found in Lake Ontario waters is very close
to 11.5 mg/1, which is well below any standards for water use. Since
1900, when sodium and potassium were reported in Lake Ontario as 6
mg/1, an almost twofold increase has occurred (Beeton 1956) in the
concentration of sodium; this increase can only be attributed to man-
caused pollution.
Biochemical Oxygen Demand(BOD)
Biochemical oxygen demand determinations were made on the water
samples collected in the lake. The standard 5-day 20 C°BOD was
used in this study. The BOD of a sample of sewage, industrial waste,
or water is a measure of the concentration of decomposable organic
matter in that sample. The BOD concept involves not only the
amount of organic material which is decomposable by bacteria, but
also the rate at which it will decompose aerobically. The results
of Cruises 102, 103, and 104 show that in Lake Ontario, because of
the low values observed, the BOD test is of limited value. All surface
values were less than 3 mg/1; most of them were well below 2 mg/1,
and the deeper waters were usually less than 1 mg/1. One surface
station (37) has a BOD of 7.8 mg/1. More important, 60 percent of
all depths sampled had a BOD of less than 1 mg/1.
Dissolved Solids
Concentrations of dissolved solids vary little in Lake Ontario.
The Mean concentrations observed were 175 mg/1 in the spring,
5-27
-------
TABLE II
WEIGHTED AVERAGES OF CHEMICAL PARAMETERS FOR LAKE
ONTARIO
Magnesium
Calcium
Silica
Chloride
Sulfate
Nitrogen:
Organic
Ammon i a
Nitrate
Phosphate:
Total
Soluble
Specific Conductance
Dissolved Solids
Alkalinity
Chemical Oxygen Demand
Dissolved Oxygen
DEEP WATER
Cruise
102
8.9
45
1.56
24.7
31.3
0.29
0.06
0.34
STATIONS
Cruise
103
9.4
46
1,18
24.7
30.7
0.21
0.04
0.31
.0163
.0163 .0131
320
175
97
6.9
13.6
312
194
95 .
7.4
11.9
Cruise
104
9.4 mg/1
43
0.85
24.6
29.5
0.20 " (N)
0.07 " (N)
0.41 " (N)
.0196 " (P)
.0163 " (P)
323 Mmhos (925°C
183 mg/1
100
6.8
11.6
-------
190 mg/1 in the summer, and 185 mg/1 in the fall. No significant
areal distribution of dissolved solids was observed other than the
fact that the highest values occurred near river mouths and large
cities. In Lake Ontario, the dissolved solids consist principally
of sulphates, bicarbonates, carbonates, and chlorides.
Potassium
Potassium was determined only for Cruise 102. The results were
so uniformly distributed that it was felt to be of little water-
quality significance. The potassium range was between 1.4 mg/1 and
2.1 mg/1 for the lake.
Conclusion
Table II shows weighted averages* for all (deep water) chemical
observations made in Lake Ontario. In conclusion, the results of
this study and those of previous studies, notably Beeton 1962,
point to the continued increase of chemical input to Lake Ontario.
* The averages were weighted in relation to total water mass
represented in all individual water samples taken at the
various depths and are based on Figure 2-2.
5-28
-------
Chapter 6
PHYSICAL CHARACTERISTICS
Introduction
Circulation studies of Lake Ontario were begun in August 1964.
Their purpose was to determine the water circulation of the lake, to
establish the cause and effect relationships so as to be able to predict
the movement of pollutants occurring in, and being discharged into, the
lake, and to develop a more accurate description and understanding of
the physical, biological, and chemical phenomena of the lake. To
accomplish this, 17 current-metering stations were set in Lake Ontario.
The current meters were Richardson type self-contained recording in-
struments clock-activated periodically (every 30 minutes in this case),
recording directional and speed data for one minute on 16 mm film and
then shutting off. At each station, current meters were suspended at
depths of 10, 15, 22, and 30 meters, and every 30 meters thereafter.
Temperature recorders were also installed. A recording anemometer
was mounted on an anchored surface buoy at each station, except during
the winter months. Figure 6-1 is a schematic diagram showing the
make-up of a typical current-metering station. The stations were in
operation for 14 months, August 1964 to early November 1965. In order
to supplement the current data obtained from these 17 stations, several
temporary nearshore stations were operated.
6-1
-------
NAVIGATION LIGHT
WIND RECORDER
TEMPERATURE RECORDER
SUBSURFACE BUOY
TEMPERATURE RECORDER
CURRENT METER
TEMPERATURE RECORDER
CURRENT METER
TYPICAL CURRENT METERING STATION
FIGURE 6-1
-------
Factors Governing Water Circulation
Four principal factors govern water motion in Lake Ontario:
wind, its velocity and direction; water temperature, as it affects
density variations within a water column; barometric pressure, as regards
to high and low pressure cells, their areal extent and magnitude; and
inflow from the Niagara River*, which establishes a gradient flow from
its mouth to the lake's outlet. All four factors are acting on the water
mass, but the dominant factor is the wind over the water surface. Other
factors, in addition to those above, are the harmonic reinforcement or
attenuation due to the physical shape of the lake basin and the rotation
of the earth, or the Coriolis effect.
Winds
The wind data collected at the current-metering stations shows
that the prevailing, or net transport, direction is from the southwest
(Figure 6-2) in the summer and fall months. In winter and spring months,
data from land stations show a slight northerly shift in the prevailing
winds; the directions are from the west to northwest. Monthly histograms
from lake stations that are near the shore show the effects of onshore
and offshore winds, which skews their directional modes. The direction
*The importance of the steady Niagara inflow on circulation is difficult
to assess. In the area of Station 18 (Figure 6-13), it is quite important,
but its real influence on the basis of physical factors alone is not
adequately known. The reader should refer to the biological and chemical
sections of this report.
6-2
-------
I
-N-
O 10 20 3O 40mi
TORONTO
M£XKO
tar
C
33
m
HAMILTON
LEGEND
• Long Term Stations
© Short Term Stations
Net Wind Direction
Net Current Direction
Net Surface Circulation/During Period of Stratification
and Net Wind Direction
-------
30 %H
20 -
10 -
30 FEET
% -
20
10 -
50 FEET
-N-
30% _|
20 -
10 -
75 FEET
30%-I
20 -
10 -
100 FEET
POLAR HISTOGRAMS OF STATION 18 SHOWING NET FLOW
FOR PERIOD AUGUST TO OCTOBER, 1964
FIGURE 6-3
-------
of net wind transport corresponds well with the direction of the pre-
vailing land winds. However, the total flow directions do not correspo^
so well. Winds observed over the lake quite often have no readily
apparent relation to the winds on land. Also, due to the altering of
air masses passing over the lake, lake winds vary from one area of the
lake to another. Thus, it would be difficult to predict the direction
of lake currents solely from shore-based stations without a lake refer-
ence.
The average wind velocities observed over the lake at a height of
4 meters were about 15 miles (24 km) per hour. The empirical relation
between winds and surface currents observed by previous investigators
is that currents travel approximately 45° to the right of the mean wind
direction, and current velocities are approximately 2 percent of mean
wind velocity. Our data show surface currents in Lake Ontario to flow
approximately 35° to the right of the mean wind direction and current
velocities slightly less than 2 percent of the wind velocity. In
consideration of the data above, if should be pointed out that the so-
called "surface" current meter was approximately 10 meters below the
surface, and interpolation of the observed data suggests that surface
velocities are higher than 2 percent, possibly 3 percent of the wind
velocity, and that current directions at the surface are less than 35°
6-3
-------
to the right of the mean wind direction. These differences from
previous observations by other researchers on various lakes can
probably be explained by the shape of the lake basin, the placement
of the current meters, and the fact that the long axis of the lake
is nearly aligned with the mean wind direction.
Temperatures
Lake Ontario is a dimictic lake, having a surface temperature above
13°C in summer and below 4°C in winter, a large thermal gradient, and
two top to bottom circulation periods, one in spring and one in fall.
In the summer, the water becomes divided into an upper layer of
warm, readily circulating, turbulent water called the epilimnion, and
a lower layer of cold and relatively undisturbed water called the
hypolimnion. The layer separating the epilimnion and hypolimnion, a
region where a rapid temperature change takes place, is called the
thermocline. When the lake is thus stratified, the waters in the
hypolimnion (the lower layer) are physically and chemically isolated.
As a result, little oxygen replacement takes place in this zone
during this period and any chemical or biological system must operate
on a reserve supply. Fortunately, in the case of Lake Ontario, 85
percent of the lake's volume is in the hypolimnion. This is not the case
in the shallow-water lakes, such as Lake Erie, where less than 20
percent of the total volume is contained in the hypolimnion, and serious
oxygen depletion is common. During this period of stratification,
6-U
-------
the volume of water with which a pollutant could mix is greatly
reduced. What may be considered a safe input in the winter months,
when the lake is essentially isothermal, may in summer months be
critical, particularly in embayments during periods of quiescence.
In the winter months, the lake again becomes stratified, but the
stratification is not as pronounced as in summer, so that for
practical purposes the lake can be considered to be essentially
isothermal. At this time, the bottom layer will again be made up of
water that is denser than the surface water. Its minimum temperature*
however, will be about 2°C (Rodgers and Anderson, 1963), while the sur^
layer may cool to as low as 0°C. Lake Ontario usually does not freeze
over in the winter. Thus, in winter there is a layer of warmer but
denser water at the bottom of the lake and a colder but lighter layer
at the surface. The period of thermal change between summer and
winter conditions is called the spring or fall overturn.
The lake begins to stratify in late May, reaching its maximum
heat content in August. From September, the epilimnion begins to cod
until the stratification becomes unstable and overturn occurs, usually
in conjunction with a storm. This fall overturn can occur as early aS
October; usually, however, it occurs some time in November. A point
to remember here is that while the lake is cooling and the temperature
of the epilimnion becomes less, the thickness of the epilimnion becomes
greater because of increased mixing.
6-5
-------
A1
Gibraltar Pf.
Niagara River
Prince Edward
Point
0- V
300-
Little Sodus
Bay
TEMPERATURE PROFILES FOR AUGUST, 1964
FIGURE 6-4
-------
Figure 6-4 shows three temperature profiles of the lake during
the month of August. The isotherms are depressed on both the northern
and southern side of the lake and bulged upward in center. This type
of thermal structure is what we would expect if the water circulation
were counterclockwise; thus, the temperature data, in general, supports
the observed summer current-metering data.
During approximately seven months of the year, the water of the
Niagara River is warmer and, therefore, less dense than the Lake Ontario
water that is below the thermocline. This means that during this time
Niagara River water mixes only with waters in the epilimnion and that
the retention time for Niagara River water is short if compared to what
is normally considered the overall retention time of the lake.
During the spring and sometimes in the fall, when the main body of
lake water is essentially isothermal, a horizontal stratification occurs
along the shoreline (Figure 6-5). In the spring, the water of the
rivers entering the lake are warmer than the lake water; this, in con-
junction with more rapid heating of the inshore waters, causes a strong
density interface, the "thermal bar-" (Rodgers, 1965), to develop at the
4°C isotherm or temperature of maximum density. Development of the
thermal bar begins in local embayments and areas of stream inflow. At
times the thermal bar may encircle the lake, separating the main body
6-6
-------
IO°C
5°C 4°C
<4°C
Wot«r Temperature Lett
Than Maximum Density
THERMAL BAR OR TEMPERATURE
OF MAXIMUM DENSITY
o
c
m
SPRING THERMAL BAR WITH ASSOCIATED VERTICAL CIRCULATION, AFTER RODGERS/65
-------
of lake water from inshore waters. Implicit in the development of a
thermal bar is the fact that it can only exist when water masses above
and below the temperature of maximum density are present and the fact
that it is a lake boundary condition.
In the fall, the conditions of thermal bar development are reversed,
However, the fall thermal bar is not as extensive or as well developed
as the one that occurs in the spring.
Figure 6-6 shows the lake surface temperatures during Cruise 102.
The isotherms in the western end of the lake are as one would expect at
this time of year, with the warmer waters inshore. This thermal struc-
ture agreed with the lake's circulation obtained from current-metering
studies. The areal influence of the Niagara River is also readily
apparent.
During Cruise 102 the winds shifted from the prevailing westerly
direction to the northeast. The effects of this are seen in the central
and eastern ends of the lake. The 4°C, 5°C, and 6°C isotherms have
apparently been displaced southward and warmer waters are moving south-
west from the bay area north of Duck Island. These observations agree
with the current-metering studies in that at Stations 16 and 17 in the
eastern end of the lake near Duck Island a flow towards the southwest
at the 10 meter level was observed and a compensating north-northeast
flow at the 30 meter level occurred.
6-7
-------
3!
o
c
a>
m
HAMILTON
SURFACE TEMPERATURES
CRUISE 102
NOTE! Temperature in °C.
-------
Data from Cruise 103 (Figure 6-7) shows a warm pool of water in the
eastern end of the lake off of Oswego. The isotherm distribution
suggests that this pool formed along the southern shore near Rochester,
New York. The areal extent of this warm pool corresponds to the area
of low light penetration also found during this cruise (See Figure 3-9).
There is a strong suggestion that the shallowness of the trophogem'c zone
observed at this time was due to biological activity, although confirmation
of such activity is lacking.
Figure 6-7 also shows the existence of colder waters along the
northern shore. It may be that deep, cold waters moving along the
northeastern rim of the lake are diverted westward and forced upward
as they pass along Scotch Bonnet Shoal, mixing with and displacing other
surface waters; this westward flow is focused somewhat in the vicinity
of Toronto.
The temperature distribution observed during Cruise 104 (Figure 6-8)
shows water in the vicinity of Scotch Bonnet Shoal being drawn southward.
This suggests that there is a counterclockwise circulation in the
eastern end of the lake. The temperature structure in the western end
of the lake suggested that another counterclockwise circulation is occur-
ring here, also.
6-8
-------
o
c
TO
HAI.CILTON
SURFACE TEMPERATURES
CRUISE 103
NOTE! Temperature in °C.
-------
CD
C
33
m
en
i
CD
HAMILTON
SURFACE TEMPERATURES
CRUISE 104
-------
Currents
Two distinct net surface circulations occur in Lake Ontario. One
circulation pattern occurs when the lake's water mass is stratified,
and the other pattern is developed when the lake's water mass is
isothermal.
When the water mass is stratified (June to November), the net
surface flow (Figure 6-2) is well developed toward the east along the
southern shore, with a lesser return flow to the west along the northern
shore; the return originates in the area of Scotch Bonnet Shoal. This
western return flow is made up in part of deeper waters flowing northwest
from the eastern basin, which, after making contact with the rim of the
lake, are diverted upward and to the west. In the eastern end of the
lake, flows are generally towards the northeast and are less sharply
defined than in the western end of the lake. The surface circulation
in the area of Scotch Bonnet Shoal, due principally to its bathymetry,
varies greatly with the frequent development of eddies. The net surface
flow of what is essentially Niagara River water is strongly developed
towards the east. There is a suggestion of a gyral occurring, at times,
in the western end of the lake. If this gyral is there and is strictly
a counterclockwise surface flow, retention times for a pollutant would
naturally be longer and some build-up could occur.
6-9
-------
This net circulation pattern reaches its maximum development in
September and remains dominant until November.
In November, fall overturn occurs and the lake's water mass becomes
essentially isothermal; also, the direction of the prevailing winds
shifts and increases in velocity so that the winds are now principally
from the west-northwest, whereas before they were from the southwest.
As a result, the whole net surface flow of the lake is eastward and a
bottom return flow is developed westward, or, -in other words, the
circulation develops a vertical tendency, with the surface layer in the
western end being displaced to the east and replaced by deeper water
(upwelling). As the surface layer moves eastward, it cools and mixes
with other surface waters. Other waters sink to replace the bottom
water being displaced westward. This pattern lasts until the lake
again becomes stratified and the winds become more southerly, which is
some time in June.
The average effective velocity (the velocity of net water transport)
is approximately 5 cm/sec, in summer months and 7 cm/sec, in the winter
months. The average velocity is on the order of 15 cm/sec, in the
summer months and 21 cm/sec, in the winter months. Velocities observed
ranged from the starting speed of the current meters, 0.5 cm/sec., to
over 50 cm/sec.
6-10
-------
The surface waters of Lake Ontario can respond very rapidly to
wind stress. A current change less than six hours after a major wind
shift is common in mid-lake. In inshore areas, the response is even
more rapid. The net circulation, while on a long-term basis may be
considered the circulation pattern of the lake, exists only for short
Periods of time. One week would be considered a long period of time
for the net circulation flow pattern to be operating. Figures 6-9,
6^10,6-11, 6-12. 6-13, 6-14, 6-15, and 6-16 show what the circula-
tion of the surface waters are under a mean wind condition and areas
where upwelling may occur. The data for these drawings were taken
by visually comparing graphs that show velocity and direction for
both winds and currents, selecting times when major changes of winds
occurred (10 miles per hour [16 km/hr] and 90° in direction), and then
looking for and noting changes in current direction and magnitude.
While this is a tedious procedure at best and accuracy is not of the
highest order, it is felt that the results are fair (the problem of
air-sea interaction is a difficult one and, as a step towards studying
it, a computer program that will do a straight statistical analysis
°f the data as regards wind speed and velocity and current direction
and speed is presently being initiated).
Also, the circulation shown should be considered only on a short-
6-11
-------
o
c
3)
n
CIRCULATION OF LAKE
NORTH WIND
-------
CIRCULATION OF LAKE
NORTHEAST WIND
-------
c
•33
m
ov
HAMILTON
CIRCULATION OF LAKE
EAST WIND
-------
to
33
m
t
ro
-V-—+•
HAMILTON!
CIRCULATION OF LAKE
SOUTHEAST WIND
-------
c
X
m
en
CIRCULATION OF LAKE
SOUTH WIND
-------
CIRCULATION OF LAKE
SOUTHWEST WIND
-------
o
c
3J
m
CIRCULATION OF LAKE
WEST WIND
-------
x
m
I
5
CIRCULATION OF LAKE
NORTHWEST WIND
-------
term basis. For example* if the wind is strong from the southwest,
a flow towards the east will naturally result; however, if it blows
from this direction long enough the waters that are moved eastward will
pile up on the windard shore and, particularly if wind intensity is
diminishing, will cause the generation of a return surface current
flowing against the wind. Needless to say, the most perplexing prob-
lem as regards to current-metering studies,using a recording type
instrument, is trying to establish an accurate time base.
Littoral Drift
The currents in the inshore areas are most important as re-
gards the supply of nutrients for plant and fish life in the areas
where light penetrates to the bottom, the movement and dispersion
of pollutants discharged into the inshore area by streams and out-
falls, and in their effect upon the quality of water at water supply
intakes. (See section on Rochester Embayment).
The littoral drift in Lake Ontario, because of its rather even
oval shape, is much as one would expect. The flow along the southern
shore is eastward and the flow around the northern shore is variable
east of Scotch Bonnet Shoal (Figure 6-17) and becomes westward west of
Scotch Bonnet Shoal. This inshore current focuses its energy somewhat
at, but parallel to the Toronto area. This probably is the reason
for the development of Gibraltar Point, at Toronto, with its very
6-12
-------
HAMILTON
LITTORAL DRIFT
-------
steep sides. At either end of the lake, the littoral drift is variable,
dependent upon the set-up of the lake's surface waters at any particular
time.
Bottom Currents
During the summer of 1965, three hundred and fifty seabed drifters
(bottom drogues) were released in Lake Ontario in order to determine
the character of the bottom drift. These drifters are mushroom-shaped
and have a long stem. They are given a slight negative buoyancy by
the addition of a small weight added to the end of the stem. A small
label is attached so that anyone finding a seabed drifter can return
it with the recovery location noted.
Of the 350 seabed drifters released, only 16 were recovered.
This low recovery rate, notably from the eastern basin, suggests that
bottom current velocities are not strong enough in Lake Ontario to move
the seabed drifters out of the deeper parts of the lake onto shore.
Another possibility is that some beached drifters were not found, owing
to poor public access to the shore.
Eight seabed drifters were dropped well out in the lake northeast
of the Niagara River. These are significant in that the two most
northeastern ones, while being fairly close initially, traveled
in opposite directions, and the recovery paths of the others crossed.
6-13
-------
10 0 10 20 30mi
HAMILTON
NOTE! • Plac« dropptd
BOTTOM DRIFT AS
INTERPRETED FROM
SEA-BED DRIFTERS
-------
Two drifters dropped at the same location (N.E. Niagara River) ended
up in opposite locations, one near 30 Mile Point and the other between
Hamilton and Toronto. This seabed drifter was recovered more than two
years after the one found at 30 Mile Point which was recovered about
two months after it was emplaced in the lake. The pattern of recovery
suggests (Figure 6-18) that a counterclockwise bottom circulation
exists in the western end of the lake, the area! extent of which
corresponds to the area of the western basin.
All of the other seabed drifters that were recovered had been
placed within a few miles of shore, where bottom currents naturally
would be stronger. The overall pattern of recovery agrees with the
current-metering data. None of the seabed drifters dropped in the
deep waters of the eastern basin were recovered.
Rochester Embayment
Of special interest in water pollution control is the effect that
pollution, stemming from several sewer outfalls and the Genesee River,
has on bathing beaches and various water intakes within the Rochester
Embayment.
Braddock Point to the west and Nine Mile point to the East form
the general limits of the Rochester Embayment. The total area of the
Bay is approximately 35 square miles (90 sq, km.), and it contains
6-iU
-------
LAKE
-N
ONTARIO
C
3)
m
(D
i
(C
Proposed
Water
Intake
ROCHESTER EMBAYMENT
-------
approximately 44 billion cubic feet (1.3 billion cubic meters). The
average stream flow of the Genesee River, the principal stream discharging
into the Bay, is 2,726 cubic feet/sec. (77 cubic meter/sec.).
The Lake Ontario Program Office placed a total of five current-
metering stations within the Embayment (Figure 6-19) in order to
determine what the water circulation is and how it relates to the winds
and the movement of pollutants. Station 19 was in operation from Novem-
ber 15, 1964, to December 3, 1964, and was located on the western side
of the Embayment near the Monroe County Water Authority's intake at a
depth of 14 meters. Stations IE, 2E, and 3E were in operation from
November 1965 to May 1966. Station B was a part of a series of tem-
porary stations that were in operation during July 1965.
Temperatures
The temperature characteristics of the Rochester Embayment are
much like those of the rest of the lake. Stratification develops in
May-June and lasts until November. During approximately eight months
of the year, the waters of the Genesee River are warmer and therefore
less dense than the Embayment waters. This means that during this time
Genesee River water will float out on top of the Embayment's surface
waters and be in a position to be most readily affected by the winds.
6-15
-------
RELATION OF WINDS AND CURRENTS IN ROCHESTER EMBAYMENT.' STATION 19
0
U
X.
S
o
3
Wind Velocity in
Milts p«r Hour.
Cjrnnt Vtlocity
in Cm. per S«c.
15
UJ
X
I
16 17 18 19 20 21 22 23 24 25 26
NOVEMBER 13-39,1964
27
28
29
-------
The important point here is that, while the volume of water
moving through a prismatic cross-section of the Embayment at any
one time is huge compared to the discharge of the Rochester Sanitary
Outfall and Genesee River, the waters from the Genesee River and the
Sanitary Outfall are confined generally to a thin layer on the surface.
Pollutants can thus be readily transported in any direction about the
Embayment by the winds until the polluted layer is mixed with the lake
waters. Throughout the summer months this mixing will occur only in
the epilimn ion. It is fortunate that most of the time the pollution
in the Embayment is initially confined to the surface waters; otherwise
the water intakes would be affected.
Currents
There exists a very close relation between wind direction and
current direction and between wind velocity and current velocity in
the Rochester Embayment (Figure 6-20). The response of the water
mass to a change is quite rapid, sometimes taking less than four
hours. Except for times when a current reversal is taking place,
the currents move either in a westerly or an easterly direction and the
flow of the Genesee River and the discharge from the Rochester Sani-
tary Outfall will be included. Both the westerly and easterly flow
6-16
-------
have a tendency to move inshore, particularly the surface waters.
Winds from the northwest (because of the shape of the Embay-
ment) at times generate a westerly current. As the winds come more
from the north, the likelihood of a westerly flow increases. Winds
from the north and northeast will definitely generate a current
flowing toward the west. This current is probably the most im-
portant as regards pollution to the western beaches and the water
intakes in that it has a strong tendency to slide the surface
waters into shore where they can concentrate. Added to this is
the fact that winds from these directions will most likely be
somewhat higher in velocity than winds from other directions.
Winds from the east and southeast will also cause currents
to flow westerly; however, this current will tend to move surface
waters away from shore. Winds from the west-northwest, west-southwest,
south-southeast will generate an easterly flow. The current genera-
ted by a west-northwest to west wind will have a strong inshore
tendency; the tendency will be reduced as the wind comes more from
the south.
Predictions of current directions based on wind records for a
five-year period from the U.S. Coast Guard Station at Rochester,
N.Y. are that currents flowing towards the east will occur annually
55 percent of the time, currents flowing to the west will occur 35
6-17
-------
percent of the time, and currents will be in the process of reversal
10 percent of the time.
Usually, during a period of wind change, from west to northeast,
for example, there is a period of calm at which time the current
velocities become quite low. A possible hazard lies in the fact
that during this period of quiescence a pool of polluted water
could form in the area of the sewer outfall, spreading out on the
surface, and then, as the wind shifts to the northeast and picks
up in velocity, the polluted water could be moved rapidly inshore,
affecting the bathing areas. A continuing shift in wind conditions
and inshore turbulence would break the pool up and move it away.
Thus, no biological evidence of this pollution would exist, unless
a sample was fortuitously taken during this period. Such con-
ditions as this rapid in and out movement of water could occur in
a day or less. Further, if, after the sample was tested and it
was determined that pollution was serious enough to close the
beaches, the decision would be a day late and the beaches could
be closed because of pollution that was no longer existing. To
carry it further, if the winds had a periodicity of 24 hours, beaches
might be open when pollution existed and closed when no pollution
existed. Obviously, an understanding of the relation between wind,
currents, and bacteriology is needed in order to make intelligent
decisions.
6-18
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Chapter 7
SUMMARY AND CONCLUSIONS
SUMMARY
Morphology
Lake Ontario has a large volume of water mass per unit surface area,
with approximately 85 percent of the water mass during the period of
stratification below the epilimnion. This physical characteristic has
far-reaching effects on the biological and geochemical systems in the
lake. For example, a large reserve of nutrients and oxygen exists in
the hypolimnion.
The Niagara River, with a mean annual inflow into Lake Ontario of
approximately 200,000 cfs is by far the greatest hydrologic factor in-
fluencing the lake environment.
Most of the streams draining into Lake Ontario are characteristic
of limestone terrains, having high flows in the spring and having very
low flows in the summer.
Due to circulation patterns and summer stratification, the mean
retention time for inflowing water is estimated to be over 15 years.
While the Lake Ontario Basin is considered to have a continental
climate, the lake has a moderating effect and brings to the area in-
fluences of a marine climate.
7-1
-------
Lake Ontario lies wholly in Paleozoic rocks of Ordovician Age
excavated along the axis of a former valley by glaciers in Pleistocene
time. The common rocks are shales and limestones.
An oxidized sedimentary microzone exists at the mud water inter-
face.
Most of the sedimentation is occurring in the western end of the
lake off of the Niagara River. Normally, the lake sediments grade
laterally, from the shore, from sand to silt to clay.
Biology
The biota of Lake Ontario represent the overall effect on the
environment of the chemical and biological systems existing in the lake.
The benthic fauna of Lake Ontario is comprised of seven principal
organisms. Two types, Amphipods (scuds) and Oligochaeta (sludgeworms),
constitute 95 percent of all organisms collected; the remaining 5 percent
consists of Sphaeriidae (fingernail cjams), Chironomidae (bloodworms),
Isopoda (aquatic sow bugs), and Hirudinea (leeches) in order of impor-
tance. Amphipods were the dominant organisms at all sampling stations
except one near the mouth of the Niagara River.
Areas where higher levels of biota generally existed were the
western end of the lake (in the Toronto-Hamilton-Niagara River area)
near the mouths of the Genesee, Oswego, and Black Rivers and Mexico Bay.
7-2
-------
The distribution of chlorophyll concentrations reflected the
temperature and circulation patterns at the time of sampling.
Prolific growths of Cladophora were reported in the lake as
far back as 1932. The distribution of Cladophora is governed to
a certain extent by water movements, for the growths are most
prolific where currents can keep the supply of nutrients high.
Commercial fishing in Lake Ontario has declined since early
1930. The decline in the commercial fishery is related to the
decline of the desirable species, such as lake trout and cisco,
and is not indicative of the total fish life contained within the
lake, inasmuch as the numbers of certain other species of fish have
increased, particularly the alewife, white perch and smelt.
An annual die-off of alewives occurs in Lake Ontario. Decompo-
sition of these fish enriches the inshore waters with large amounts
of nutrients, notably phosphorus. This may stimulate the heavy
growths of Cladophora that begin to develop in May.
The microbiological study in Lake Ontario investigated the
parameters of total coliform and total plate counts. Microbiological
activity was found to be greatest in the areas of municipalities and
affected by the circulation patterns.
Chemistry
The chemistry of the lake waters is constantly changing, adjust-
7-3
-------
ing to biological, physical, and chemical demands or changes. Many
elements and/or compounds are part of a biogeochemical system. Con-
sequently, a measurement of a particular element or compound represents
only what is existing in that part or phase of the system; it does not
represent the quantity or speed of an element or compound moving
through the system. In a lake, such as Ontario, the concept of
availability to a biogeochemical system as opposed to concentration
of a dissolved substance per se is important since these lakes have a
stability (long retention time) unlike streams, where the chemical
part of these biogeochemical systems can, and in some cases may,
reach and remain at equilibrium and may or may not remain in that
state.
Phosphorus as phosphate is part of a complex biogeochemical
cycle in the lake environment, the details of which are not clearly
understood.
Concentrations of phosphate are highest in the inshore areas
particularly near cities and rivers.
The iron cycle affects the phosphate cycle.
One ideal solution does not exist for reducing the algal growths
in Lake Ontario, and several methods of attack on the problem must be
used. However, a program of phosphate control, including maximum
removal of phosphates at treatment plants, may, in the case of Lake
-------
Ontario, bring the most rewarding results. The reason for this is
that this lake has a tremendous oxygen reserve in the hypolimnion,
having a small surface area in relation to volume. It has been
known for some time that a self-regulating system exists in the
phosphate cycle between the water mass and lake muds. The oxidized
sedimentary microzone which develops at the mud-water interface is
rich in ferric hydroxide and ferric phosphate. The microzone forms
a chemical barrier that hinders phosphate ions from the reduced
sedimentary layer beneath it from going into solution and, also,
assimilates material falling to the bottom. This oxidized sedi-
mentary microzone exists in Lake Ontario for most of the year and
quite likely all year.
The oxygen data suggest that serious oxygen depletion does not
occur in the main part of the lake. The reason why no significant
oxygen depletion occurs is that 85 percent of the lake's water
mass is below the thermocline during summer stratification, so a
large reserve of oxygen is available during the period of stratifi-
cation.
The lowest values of dissolved oxygen were near 70 percent
saturation in the bottom water. The dissolved oxygen in the sur-
face waters was very near saturation or above saturation.
7-5
-------
Since the early 1900's chloride content has steadily increased in
Lake Ontario. The concentration of chloride is now approaching 30
mg/1.
Concentrations of dissolved silica in Lake Ontario are related
to the diatom populations. Silica is taken up from the lake water
during the spring by diatoms. Later in the fall, the silica is
recycled back into the water from the skeletal material of the
dead diatoms.
The biochemical oxygen demand test (BOD) in Lake Ontario is
of limited use because of the low values observed (generally 3
mg/1 or less).
The mean concentration of dissolved solids in Lake Ontario
ranged from 175 mg/1 in the spring to 185 mg/1 in the fall. No
significant areal distribution was observed, other than that the
highest values were observed near river mouths and large cities.
Potassium concentrations ranged from 1.4 to 2.1 mg/1.
The greatest single source of pollutants in Lake Ontario is
the Niagara River inflow.
The results of our study point to the continued increase of
chemical input to Lake Ontario and the resultant deterioration of
the lake water.
7-6
-------
Physical
The wind data show that the prevailing, or net transport, direc-
tion is from the southwest in the summer and fall months (no data are
available for the winter months). The average wind velocities were
about 15 miles (24 km/hr) per hour.
Lake Ontario is stratified during the summer and fall months.
During this period of stratification, the volume of water with which
a pollutant and/or inflowing stream can mix is greatly reduced. At
the time of maximum stratification, the thermocline is approximately
30 meters below the surface.
During the late fall and early spring a vertical stratification
develops which, in effect, separates the inshore and the lake water.
This vertical stratification is called the 'thermal bar1 and may or
may not act as a barrier to the mixing of inshore and offshore lake
waters.
The temperature structure of the lake in the spring, summer and
fall months suggests an overall counterclockwise circulation.
Two distinct surface circulations occur in Lake Ontario. One
circulation pattern occurs when the lake's water mass is stratified,
and the other pattern is developed when the lake's water mass is
isothermal.
When the lake is stratified the net surface circulation is
counterclockwise.
7-7
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The main current is east along the southern shore, with a
lesser return flow to the west along the northern shore. There is
a suggestion of a gyral occurring at times in the western end of
the lake.
The effect of the Niagara River flow is to impose an essentially
steady state gradient flow in Lake Ontario, from its mouth eastward
to the St. Lawrence River.
During the winter months, when the lake's water mass is isothermal,
the net surface flow is eastward.
The surface waters of Lake Ontario respond very rapidly to
wind stress; current changes in less than six hours after a wind
shift are common in mid-lake.
The average effective velocity (the velocity of net water trans-
port) is approximately 2 cm/sec, in summer months and 5 cm/sec, in the
winter months. The average velocity is on the order of 5 cm/sec, in
the summer months and 10 cm/sec, in the winter months. Velocities
observed ranged from the starting speed of the current meters, 0.5 cm/sec,
to over 50 cm/sec.
The circulation of Lake Ontario is such that the water from
inflowing streams and pollutants discharged into the nearshore area
will tend to remain in the inshore zone, thus keeping the most produc-
tive zone well supplied with nutrients.
7-8
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CONCLUSIONS
The following conclusions are made as a result of studies of
Lake Ontario:
A thorough biogeochemical study should be initiated. The goal
of this study would be to find one or several biological and/or
chemical parameters that truly reflect the lake's water quality
and to determine what is the most practical approach to the proper
management of the lake environment.
When planning outfalls and intakes in Lake Ontario, an ocean-
ographic study be required, as part of an overall engineering
study for approval of such intakes and outfalls, in order to
determine the proper location or distribution of such. The study
should cover surface and subsurface currents, waves, temperature, sub-
marine topography, bottom materials, diffusion characteristics, and
amounts and quality of effluent.
An effort be made to establish a fishery on Lake Ontario,
(such as rainbow trout and/or coho salmon) so as to cut down on the
population of alewives.
The feasibility of commercial harvesting and the possible sub-
sequent conversion to fish flour of the alewives should be investi-
gated.
When evaluating the practicability or desirability of con-
7-9
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structing groins in order to stop the littoral transport of sand, the
fact that these groins also provide an ideal trap for dead fish and
Cladophora should be given consideration.
Future industrial zoning be such that it would encourage industrial
'symbiosis', that is, where an industry would live on the waste of
another; implicit in this recommendation is the concept of waste disposal
planning as part of an overall system which, in the case of the Great
Lakes and in particular the lower Great Lakes is vital.
The development of a computerized model of the total lake basin
environment should be begun, including economics, engineering, chemistry,
geology, biology, stream flow, groundwater, etc. This model would
be used to help manage the water resources of the whole basin. In the
development of this proposed computerized model, advantage should be taken
of remote sensing techniques to constantly update the model.
Stream standards should be implemented as rapidly as possible,
and these standards should be strict enough so that an improvement
in lake water quality will result. Along with this is the necessity
of setting standards for wastes discharged directly into the lake.
An intensive program of applied research to develop a substi-
tute for the phosphate ion in detergents, petroleum additives, paints,
etc. must be carried out.
7-10
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