WATER QUALITY MEASUREMENTS FOR PINE LAKE, 2011
PINE LAKE SUMMER 2011
Study performed: Spring – 15 April 2011; Summer – 15 August 2011
Preliminary water quality report submitted: 13 February 2012
Prepared by: David J. Jude, Ph.D., Limnologist, Fishery Biologist
FRESHWATER PHYSICIANS, INC
5293 DANIEL, BRIGHTON MI 48114
810-227-6623
INTRODUCTION
Our water quality survey is done by visiting a lake at least twice, once in the spring just after spring turnover in the
lake (this part needs to be done as soon as possible), when the lake is well mixed and we can get a measurement of the
nutrient status of the lake. Since it is prudent to continue Wally Fusilier’s program, we sampled his 10 in-lake stations and
two additional ones (stations 11, 12) were located in the canal and at Lea Renterghem’s Bay in the wetland area north of
the lake. The stations we sampled included some we designated as master stations, where we also procured a dissolved
oxygen and temperature profile and collected water chemistry samples at surface, mid depth, and bottom. Our second trip
is the major one and we do this in summer, during maximum stratification of the lake, a time of great production,
sometimes stress, and a time when we can assess the entire ecosystem of the lake. We also collected well samples to
determine if there were excessive chlorides in the groundwater.
From Fusilier (2009): Pine Lake is a 370-acre natural, moderately hard-water, kettle lake located in Sections 11, 12,
13 & 14, West Bloomfield Township (T2N R9E), Oakland County, Michigan. The lake has a maximum depth of 95 feet
(station 10), a water volume of 8,163 acre-feet, and a mean depth of 22.1 feet. It has 23,018 feet of shoreline. The
elevation of the lake is 930 feet above sea level. There are no islands in the lake. Although the lake bottom is quite
irregular with 94 percent of the lake being 50 feet deep or less, there are two basins deeper than 50 feet. The deepest
basin (95 feet - station 10) is located in the narrowest central part of the lake off the Pine Lake Country Club point. The
longitude and latitude of the 95-foot deep hole is 83° 20.482 W and 42° 34.474 N. A 70-feet-deep basin is located directly
west of the 95-foot basin near the west end of the lake.
The size of the watershed, which is the land area that contributes water to the lake, but does not include the lake,
is 806 acres. The drainage area, which includes the lake and the watershed, is 1,176 acres. The watershed to lake ratio
is 2.17 to 1, which is small for a Michigan inland lake. Because of this small ratio, the lake flushes relatively slowly, about
once every 8.4 years, on an average. This long flushing rate has a significant impact on activities around the lake
because the lake flushes only about 12 percent of the pollutants that get into it each year. There is a single inlet (canal
system with wetlands) which enters the lake on the northeast corner. The outlet is on the southwest end. Water from Pine
Lake flows into Orchard Lake then into the Clinton River. The Clinton River flows into Lake St. Clair below Mt. Clemens,
Michigan.
METHODS
Sampling Times
The spring survey is done as soon as we can get to the lake after the ice departs. The lake is isothermal (same
temperature and nutrient values from top to bottom) at this time. We came to the lake and collected surface water
samples at the 11 stations that were previously sampled. In addition, we measured the dissolved oxygen and water
temperature profile (every meter of depth) at the deep station 6 plus a suite of water chemistry parameters (chlorides,
ammonia, soluble reactive phosphorus, nitrates, conductivity), plus a secchi disc reading for water clarity.
During late summer we again visit the lake and sampled water chemistry factors (same suite of water quality
parameters as noted above plus hydrogen sulfide) in the same manner as we did during the spring. The dissolved
oxygen and temperature profile is particularly important as it determines if there is a bottleneck of low dissolved oxygen on
the bottom in the deep basins.
Station Location
During any study we choose a number of places (stations) where we do our sampling for each of the desired
parameters. We strive to have a station in any unusual or important place, such as inlet and outlet streams, as well as in
representative areas in the lake proper. One of these areas is always the deepest part of the lake. Here we check on the
degree of thermal and chemical stratification, which is extremely important in characterizing the stage of eutrophication
(nutrient enrichment), invertebrates present, and possible threats to fish due to production of toxic substances due to
2
decomposition of the bottom sediments. The number and location of these stations for this study are noted in that
section.
Light Penetration
The clarity of the water in a lake determines how far sunlight can penetrate. This in turn has a basic relationship
to the production of living phytoplankton (minute plants called algae), which are basic producers in the lake, and the
foundation of the food chain. We measure light penetration with a small circular black and white Secchi disc attached to a
calibrated line. The depth at which this disc just disappears (amount of water transparency) will vary between lakes and
in the same lake during different seasons, depending on degree of water clarity. This reference depth can be checked
periodically and can reflect the presence of plankton blooms and turbidity caused by urban run-off, etc. A regular
monitoring program can provide an annual documentation of water clarity changes and also a historical record of changes
in the algal productivity in the lake that may be related to development, nutrient inputs, or other insults to the lake.
Water Temperature
Thermal stratification is a critical process in lakes which helps control the production of algae, generation of
various substances from the bottom, and dissolved oxygen depletion rates. Temperature governs the rate of biological
processes. A series of temperature measurements from the surface to the bottom in a lake (temperature profile) is very
useful in detecting stratification patterns. Stratification in early summer develops because the warm sun heats the surface
layers of a lake. This water becomes less dense due to its heating, and "floats" on the colder, denser waters below.
Three layers of water are thus set up. The surface warm waters are called the epilimnion, the middle zone of rapid
transition in temperatures is called the thermocline, and the cold bottom waters, usually around 39 F (temperature of
maximum density), are termed the hypolimnion. As summer progresses, the lowest cold layer of water (hypolimnion)
becomes more and more isolated from the upper layers because it is colder and denser than surface waters (see Fig. 1
for documentation of this process over the seasons).
Figure 1. Depiction of the water temperature relationships in a typical 60-ft deep lake over the seasons. Note the blue
from top to bottom during the fall turnover (this also occurs in the spring) and the red yellow and green (epilimnion,
thermocline, and hypolimnion) that forms (stratification) during summer months. Adapted from NALMS.
3
When cooler weather returns in the fall, the warm upper waters (epilimnion) cool to about 39 F, and because
water at this temperature is densest (heaviest), it begins to sink slowly to the bottom. This causes the lake to "turnover" or
mix (blue part on right of Fig. 1), and the temperature becomes a uniform 39 F top to bottom. Other chemical variables,
such as dissolved oxygen, ammonia, etc. are also uniformly distributed throughout the lake.
As winter approaches, surface water cools even more. because water is most dense at 39 F, the deep portions of
the lake "fill" with this "heavy water". Water colder than 39 F is actually lighter and floats on the more dense water below,
until it freezes at 32 F and seals the lake. During winter decomposition on the bottom can warm bottom temperatures
slightly.
In spring when the ice melts and surface water warms from 32 to 39 F, seasonal winds will mix the lake again
(spring overturn), thus completing the yearly cycle. This represents a typical cycle, and many variations can exist,
depending on the lake shape, size, depth, and location. Summer stratification is usually the most critical period in the
cycle, since the hypolimnion may go anoxic (without oxygen--discussed next). We always try to schedule our sampling
during this period of the year. Another critical time exists during late winter as oxygen can be depleted from the entire
water column in certain lakes under conditions of prolonged snow cover.
Dissolved Oxygen
This dissolved gas is one of the most significant chemical substances in natural waters. It regulates the activity of
the living aquatic community and serves as an indicator of lake conditions. Dissolved oxygen is measured using a YSI,
dissolved oxygen-temperature meter or the Winkler method with the azide modification. Fixed samples are titrated with
PAO (phenol arsene oxide) and results are expressed in mg/L (ppm) of oxygen, which can range normally from 0 to about
14 mg/L. Water samples for this and all other chemical determinations are collected using a device called a Kemmerer
water sampler, which can be lowered to any desired depth and like the Ekman grab sampler, tripped using a messenger
(weight) on a calibrated line. The messenger causes the cylinder to seal and the desired water sample is then removed
after the Kemmerer is brought to the surface. Most oxygen in water is the result of the photosynthetic activities of plants,
the algae and aquatic macrophytes. Some enters water through diffusion from air. Animals use this oxygen while giving
off carbon dioxide during respiration. The interrelationships between these two communities determine the amount of
productivity that occurs and the degree of eutrophication (lake aging) that exists.
A series of dissolved oxygen determinations can tell us a great deal about a lake, especially in summer. In many
lakes in this area of Michigan, a summer stratification or stagnation period occurs (See previous thermal stratification
discussion). This layering causes isolation of three water masses because of temperature-density relationships already
discussed (see Fig. 2 for demonstration of this process).
4
Figure 2. Dissolved oxygen stratification pattern over a season in a typical, eutrophic, 60-ft deep lake. Note the blue area
on the bottom of the lake which depicts anoxia (no dissolved oxygen present) during summer and the red section in the
fall turnover period (there is another in the spring) when the dissolved oxygen is the same from top to bottom. Adapted
from NALMS.
In the spring turnover period dissolved oxygen concentrations are at saturation values from top to bottom (see red
area which is the same in the spring – Fig. 2). However, in these lakes by July or August some or all of the dissolved
oxygen in the bottom layer is lost (used up by bacteria) to the decomposition process occurring in the bottom sediments
(blue area in Fig. 2). The richer the lake, the more sediment produced and the more oxygen consumed. Since there is no
way for oxygen to get down to these layers (there is not enough light for algae to photosynthesize), the hypolimnion
becomes devoid of oxygen in rich lakes. In non-fertile (Oligotrophic) lakes there is very little decomposition, and therefore
little or no dissolved oxygen depletion. Lack of oxygen in the lower waters (hypolimnion) prevents fish from living here
and also changes basic chemical reactions in and near the sediment layer (from aerobic to anaerobic).
Stratification does not occur in all lakes. Shallow lakes are often well mixed throughout the year because of wind
action. Some lakes or reservoirs have large flow-through so stratification never gets established.
Stratified lakes will mix in the fall because of cooler weather, and the dissolved oxygen content in the entire water
column will be replenished. During winter the oxygen may again be depleted near the bottom by decomposition
processes. As noted previously, winterkill of fish results when this condition is caused by early snows and a long period of
ice cover when little sunlight can penetrate into the lake water. Thus no oxygen can be produced, and if the lake is
severely eutrophic, so much decomposition occurs that all the dissolved oxygen in the lake is depleted.
In spring, with the melting of ice, oxygen is again injected into the hypolimnion during this mixing or "turnover"
period. Summer again repeats the process of stratification and bottom depletion of dissolved oxygen.
One other aspect of dissolved oxygen (DO) cycles concerns the diel or 24-hour cycle. During the day in summer,
plants photosynthesize and produce oxygen, while at night they join the animals in respiring (creating CO2) and using up
oxygen. This creates a diel cycle of high dissolved oxygen levels during the day and low levels at night. These dissolved
5
oxygen sags have resulted in fish kills in lakes, particularly near large aquatic macrophyte beds on some of the hottest
days of the year.
Conductivity
Conductivity (unit of measure is microSiemens/cm) is a measure of the ability of water to conduct current and is
proportional to the dissolved solutes present. Some urban lakes with septic tanks and considerable amounts of road salt
(inputs high concentrations of chlorides) will increase conductivity values.
Chlorides
Water chemistry parameters are extremely useful measurements and can reveal considerable information about
the type of lake and how nutrients are fluxing through the system. They are important in classifying lakes and can give
valuable information about the kind of organisms that can be expected to exist under a certain chemical regime. All
chemical parameters are a measure of a certain ion or ion complex in water. The most important elements--carbon (C),
hydrogen (H), and oxygen (O) are the basic units that comprise all life, so their importance is readily obvious. Other
elements like phosphorus (P) and nitrogen (N) are extremely important because they are significant links in proteins and
RNA/DNA chains. Since the latter two (P and N) are very important plant nutrients, and since phosphorus has been
shown to be critical and often times a limiting nutrient in some systems, great attention is given to these two variables.
Other micronutrients such as boron, silicon, sulfur, and vitamins can also be limiting under special circumstances.
However, in most cases, phosphorus turns out to be the most important nutrient.
Chlorides are unique in that they are not affected by physical or biological processes and accumulate in a lake,
giving a history of past inputs of this substance. Chlorides (Cl-) are transported into lakes from septic tank effluents and
urban run-off from road salting and other sources. Chlorides are detected by titration using mercuric nitrate and an
indicator. Results are expressed as mg/L as chloride. The effluent from septic tanks is high in chlorides. Dwellings
around a lake having septic tanks contribute to the chloride content of the lake. Depending upon flow-through, chlorides
may accumulate in concentrations considerably higher than in natural ground water. Likewise, urban run-off can transport
chlorides from road salting operations and also bring in nutrients. The chloride "tag" is a simple way to detect possible
nutrient additions and septic tank contamination. Ground water in this area averages 10-20 mg/L chlorides. Values
above this are indicative of possible pollution.
Phosphorus
This element, as noted, is an important plant nutrient, which in most aquatic situations is the limiting factor in plant
growth. Thus if this nutrient can be controlled, many of the undesirable side effects of eutrophication (dense macrophyte
growth and algae blooms) can be avoided. The addition of small amounts of phosphorus (P) can trigger these massive
plant growths. Usually the other necessary elements (carbon, nitrogen, light, trace elements, etc.) are present in
quantities sufficient to allow these excessive growths. Phosphorus usually is limiting (occasionally carbon or nitrogen may
be limiting). Two forms of phosphorus are usually measured. Total phosphorus is the total amount of P in the sample
expressed as mg/L or ppm as P, and soluble P or Ortho P is that phosphorus which is dissolved in the water and
"available" to plants for uptake and growth. Both are valuable parameters useful in judging eutrophication problems.
Nitrogen
There are various forms of the plant nutrient nitrogen, which are measured in the laboratory using EPA-approved
standard methods. The most reduced form of nitrogen, ammonia (NH3), is usually formed in the sediments in the
absence of dissolved oxygen and from the breakdown of proteins (organic matter). Thus high concentrations are
sometimes found on or near the bottom under stratified anoxic conditions. Ammonia is reported as mg/L as N and is toxic
in high concentrations to fish and other sensitive invertebrates, particularly under high pHs. With turnover in the spring
most ammonia is converted to nitrates (NO3=) when exposed to the oxidizing effects of oxygen. Nitrite (NO2-) is a brief
form intermediate between ammonia and nitrates, which is sometimes measured. Nitrites are rapidly converted to nitrates
when adequate dissolved oxygen is present. Nitrate is the commonly measured nutrient in limnological studies and gives
a good indication of the amount of this element available for plant growth. Nitrates, with Total P, are useful parameters to
measure in streams entering lakes to get an idea of the amount of nutrient input. Profiles in the deepest part of the lake
6
can give important information about succession of algae species, which usually proceeds from diatoms, to green algae to
blue-green algae. Blue-green algae (an undesirable species) can fix their own nitrogen (some members) and thus outcompete more desirable forms, when phosphorus becomes scarce in late summer.
RESULTS
Station Location
We sampled at 12 stations around Pine Lake, including master stations, samples from the extensive wetlandcanal system to the north, and well samples (Table 1, Fig. 3, 4). GPS locations are provided for each station (Table 1).
Table 1. Stations on Pine Lake sampled for water quality parameters, 15 April and 15 August, 2011. Provided is a
description and GPS locations. See Fig. 3, 4 for station and Google maps.
_______________________________________________________________
Station
Description
_______________________________________________________________
1
N end of main basin near country club
N 42 35.716 W 83 20.464
2
NE side of lake near canals
3
SE side of main basin of the lake
GPS: N 42 35.243 W 83 20.053
4
S side of main basin of the lake
GPS: N 42 35.329 W 83 20.475
5
S side of lake by point between main and S basin
GPS: N42 35.382 W 83 20.878
6
On E side of the S basin
GPS:N 42 35.179 W 83 20.862
7
On W side of the S basin
GPS:N 42 35.136 W 83 21.079
8
W of station 5 on W side of the central part of the lake
GPS:N 42 35.413 W 83 20.059
9
N side of the central basin
GPS: N 42 35.467 W 83 20.896
10
W side of main basin- deepest at 95 ft
GPS:N 42 35.444 W83 20.526
11
Canal wetlands at Lea Van Renterghems
12
Canal site N of bridge
_______________________________________________________________
7
Pine Lake
Sections 11, 12, 13 & 14
West Bloomfield Township
T2N R9E
Oakland County
12
Hydrographic and sample station map
N
W
11
1
WQI
E
13
40
Sample stations
5040
10 20 30
9
S
2
40
5
10
70 60
8
40
30
20
10
5
50
40
95¥
9010
30
70
80
5
20
30
20
105
40 33
50
50
60
50
40
30
3
4
20
10
22
7
20
6
1200 feet
5
10
5
Figure 3. Map of Pine Lake showing the 12 sampling stations visited during this study. Station 13 was not sampled.
From Fusilier (2009).
8
Figure 4 . Google map of Pine Lake, Oakland County, Michigan.
Dissolved Oxygen
We measured dissolved oxygen and water temperature at four stations (2, 3, 8, and 10) in Pine Lake during 15
April 2011 (Fig. 5-8; Table 2). This day was extremely windy and the waves were 3 ft or more and it was during the spring
turnover period, hence the water temperatures were around 8-9 C from surface to bottom as expected. The dissolved
oxygen was also very high, fluctuating between 13 and 15 mg/L at or above saturation values for the water temperature.
These findings are consistent with Fusilier (2009), who found a similar pattern of cold temperatures and elevated
dissolved oxygen during the spring.
Figure 5. Dissolved oxygen (mg//L) and water temperature (C) profile for station 2 on Pine Lake, 15 April 2011.
9
Figure 6. Dissolved oxygen (mg//L) and water temperature (C) profile for station 8 in Pine Lake, 15 April 2011.
Figure 7. Dissolved oxygen (mg//L) and water temperature (C) profile for station 3 in Pine Lake, 15 April 2011.
10
Table 2. Raw dissolved oxygen and water temperature data during 15 April 2011 for Pine Lake, Oakland County MI.
___________________________________________________________________________________________
Station 2
Station 3
Station 8
Station 10
Depth(M)
Depth (ft)
Temp
DO
Temp
DO
Temp
DO
Temp
DO
___________________________________________________________________________________________
0
9
13.6
8.9
14
9.2
14.2
9.2
14.2
1
3.3
9
13.6
8.9
14.1
9.2
14.2
9.2
14.2
2
6.6
9
13.6
8.9
14
9.2
14.2
9.2
14.2
3
9.8
9
13.6
8.9
14.2
9.2
14.3
9.2
14.2
4
13.1
8.9
13.8
8.9
14.3
9.2
14.4
9.2
14.4
5
16.4
8.9
13.6
8.9
15
9.2
14.6
9.2
14.4
6
19.7
8.9
13.6
8.9
14.4
9.2
14.6
9.2
14.5
7
23.0
8.5
14
8.8
14.2
9.2
14.7
9.2
14.7
8
26.2
8.5
14
8.8
14.2
9.2
14.9
9.2
14.9
9
29.5
8.5
14.1
8.8
14.2
9.2
15
9.2
14.8
10
32.8
8.3
14.4
8.8
14
9.2
14.9
9.2
14.9
11
36.1
8.3
14.4
8.8
13.8
9.2
14.8
9.2
14.8
12
39.4
8.3
14.2
8.5
14.3
9.2
14.6
9.2
14.6
13
42.7
8.3
14.2
8.2
12.9
8.9
14.5
14
45.9
8.2
12.6
8.2
12.9
15
49.2
8.2
12.8
16
52.5
8.2
12.8
17
55.8
8.2
12.5
18
59.1
8.2
12.4
19
62.3
8.2
12.4
20
65.6
8.2
12.1
21
68.9
8.2
12.1
22
72.2
8.2
11.9
23
75.5
8
11.5
24
78.7
8
25
82.0
26
85.3
8
8
11.4
11.2
27
88.6
8
11.2
11.2
___________________________________________________________________________________________
11
Figure 8. Dissolved oxygen (mg//L) and water temperature (C) profile for station 10 in Pine Lake, 15 April 2011.
During 15 August, the water temperature profile at master stations 2, 9, and 10 (Fig. 9, 10, 11; Table 3) showed
the thermocline started around 6 m (20 ft) with water temperatures on the bottom around 10 C. Dissolved oxygen at the
deep station 10 was 0.8 mg/L at 9 m (30 ft) and eventually was zero from 14 m (46 ft) to the bottom. Hence, depths at
and below 9 m or 30 ft to the bottom (the bottom 65 ft) would be off limits to fish, since warm water fish require at least 3
mg/L. Prior data from Fusilier (2009) suggested that zero dissolved oxygen was found at a range from 29 to 45 ft (1947)
from the bottom, so our findings (46 ft) suggest slightly more dissolved oxygen was higher in the water column than
generally found in past years. Low dissolved oxygen on the bottom is also detrimental to the nutrient status of the lake,
since anoxia (zero dissolved oxygen) on the bottom of a lake allows phosphorus (along with other deleterious substances
such as ammonia) to be released from decomposing sediments. That nutrient along with others generated during
summer (ammonia) is then released throughout the water column during the fall overturn to fuel algal blooms and other
plant growth in the lake.
Figure 9. Dissolved oxygen (mg//L) and water temperature (C) profile for station 10 in Pine Lake, 15 August 2011.
12
Figure 10. Dissolved oxygen (mg//L) and water temperature (C) profile for station 9 in Pine Lake, 15 August 2011.
Figure 11. Dissolved oxygen (mg//L) and water temperature (C) profile for station 2 in Pine Lake, 15 August 2011.
13
Table 3. Raw dissolved oxygen and water temperature data during 15 August 2011 for Pine Lake, Oakland County MI.
__________________________________________________________________________
Station
10
Station 9
Station 2
Depth (m)
Depth (ft)
Temp
DO
Temp
DO
Temp
DO
__________________________________________________________________________
0
0
25.1
9.1
25.1
8.4
25.3
8.6
1
3.3
25.1
9.4
25.1
8.4
25.1
8.6
2
6.6
25.1
9.4
25
8.4
24.9
8.7
3
9.8
25
9.3
24.8
8.6
24.9
8.5
4
13.1
25
9.3
24.6
8.2
24.9
8.3
5
16.4
25
9.2
24.3
8
24.6
8.3
6
19.7
24.8
9.1
24.3
7.9
24.1
8
7
23.0
22.3
4
20
4
23.3
6.1
8
26.2
17.3
2.2
17
1.1
17.2
2.1
9
29.5
14.9
0.8
14.8
0.7
15
0.5
10
32.8
14
0.6
13.4
0.5
13.8
0.5
11
36.1
12.8
0.4
12.8
0.4
13.3
0.4
12
39.4
12
0.4
12
0
11.9
0
13
42.7
11.6
0.4
11.4
0
11.4
0
14
45.9
11.3
0
11.1
0
11.2
0
15
49.2
11.1
0
11
0
11
0
16
52.5
11
0
10.9
0
17
55.8
11
0
10.5
0
18
59.1
10.9
0
10.3
0
19
62.3
10.8
0
10.1
0
20
65.6
10.5
0
10.1
0
21
68.9
10.2
0
10
0
22
72.2
10.1
0
10
0
23
75.5
10.1
0
24
78.7
10.1
0
25
82.0
10.1
26
85.3
10
0
0
27
88.6
10
0
__________________________________________________________________________
Conductivity
We measured conductivity (ability to conduct electricity) at all 11 stations to determine if there were excessive
solutes that may provide us with clues as to inputs of other substances that are costly to measure (e.g., nutrients). High
conductivity (and chlorides are used as an indicator as well) over what might be considered “average values” for other
parts of the lake indicate there might be a source of deleterious substances entering the lake. During 15 April,
conductivity ranged from 679 uS/cm to 692 uS/cm, which are fairly consistent values (Fig. 12). The highest
concentrations tended to be found at bottom samples, with the exception of station 10, where bottom samples yielded the
lowest conductivity (656 uS/cm). Apparently there was still enough buildup of decomposition products, even though these
14
were near isothermal conditions, to increase conductivity in bottom waters. Overall these values are moderately high for
Michigan inland lakes, indicating a history of input of solutes (such as chlorides) into Pine Lake.
Figure 12. Conductivity (uS) measured at the 10 in lake stations sampled on Pine Lake, 15 April 2011. S=surface, M=mid
depth, and B=bottom.
During August, the range in conductivity values was lower than in April. The range in August was 621 uS/cm
(station 1) to 684 uS/cm for station 10 bottom, where decomposition was probably maximal (Fig. 13). The conductivity
consistently showed a direct relationship with depth. Conductivity measurements were similar in surface waters among
stations, with station 10 in the middle of the lake showing the lowest conductivity at 595 uS/cm.
Prior data from Fusilier (2004) showed results for conductivity that were comparable to what we found, with the
apparent exception that our conductivity values appear to be generally higher than what was found previously and the
trend of uniform concentrations in spring was different in our data in that there was a tendency for higher concentrations
on the bottom. Both studies found stratification of values with depth with higher concentrations on the bottom during
August, again with the exception of station 10 during 2011, which did not follow this trend.
Figure 13. Conductivity (uS) measured at the 10 stations sampled on Pine Lake, 15 August 2011. S=surface, M=mid
depth, B=bottom.
15
Chlorides
Chlorides are also used as indicators and values in Pine Lake during 15 April ranged from 80 to 112 mg/L, with
the highest value found at station 8 at the surface (Fig. 14, Table 4). There was no consistent trends with depths at the
four stations where data were collected (Table 4). Values in this range are moderate for most Michigan inland lakes, but
do indicate probable input of road salts during winter and spring. The wetland area (station 11) in April had chloride
concentrations of 103, which is similar to values in the lake, while the canal sample (station 12) yielded one of the lowest
values of all samples with 84 mg/L. This is contrary to expectations, since we hypothesized that the canal would receive
more salt runoff, runoff from the residences, and other leakage from groundwater.
Figure 14. Chlorides (mg/L) measured at the four in-lake stations at the surface for Pine Lake, 15 August 2011. Also
sampled were the wetland area (station 11) and the canal (station 12).
Table 4. Nitrates (NO3), chlorides (CL), ammonia (NH3), and soluble reactive phosphorus concentrations (mg/L) at
stations 2, 3, 8, and 10 (deepest station) in Pine Lake at the surface, mid depth and bottom, 15 April 2011.
____________________________________________________
STATION
DEPTH
CL
NO3
NH3
SRP
______________________________________________________
15-Apr-11
2
SURF
80
0.28
0.035
<0.005
2
MID-6 M
106
0.36
0.0468
<0.005
2
BOTT-11 M
104
0.41
0.2712
0.007
3
SURF
107
0.34
0.0821
<0.005
3
MID- 7 M
95
0.32
0.0905
<0.005
3
BOT-13 M
102
0.34
0.0371
<0.005
16
8
SURF
112
0.53
0.0411
<0.005
8
MID 6 M
94
0.35
0.0531
<0.005
8
BOT 11 M
77
0.27
0.0444
<0.005
101
0.34
0.1583
0.01
10
SURF
10
MID-15 M
85
0.36
0.0385
<0.005
10
BOT-25 M
100
0.36
0.0891
<0.005
______________________________________________________
During August, chlorides in Pine Lake ranged from 105 to 111 mg/L (Fig. 15), which was similar to spring data.
There was no clear relationship with depth, except at station 10, where there were higher concentrations on the bottom
(Table 5). Chlorides at the wetland (99 mg/L at station 11) in August were similar to those in Pine Lake, while in the canal
(station 12), values were the lowest (40 mg/L). Both the spring and summer chloride concentrations in the canal were
low, contrary to expectations. Obviously the canal is receiving inputs of lower chloride water, either from groundwater or
runoff which is less contaminated than what is found in Pine Lake. Snowmelt runoff in the spring and uncontaminated
ground water could lead to low values in the canal.
Figure 15. Chlorides (mg/L) measured at the 11 stations sampled on Pine Lake, 15 August 2011.
17
Table 5. Nitrates (NO3), chlorides (CL), ammonia (NH3), and soluble
reactive phosphorus concentrations (mg/L) at stations 2, 9, 10(deepest
station) in Pine Lake at the surface, mid depth, and bottom, 15 August
2011.
______________________________________________________
STATION
DEPTH
CL
NO3
NH3
SRP
______________________________________________________
15-Aug-11
2
SURF
105
<0.01
0.019
<0.005
2
MID 8 M
106
<0.01
0.039
<0.005
2
BOT 15 M
106
<0.01
0.259
0.007
9
SURF
106
0.009
0.02
<0.005
9
MID 11 M
105
0.35
0.082
<0.005
9
BOT 22 M
106
<0.01
0.400
0.006
10
SURF
107
<0.01
0.039
<0.005
10
MID 14 M
106
0.160
0.011
10
BOT 26 M
111
0.383
0.008
0.36
<0.01
________________________________________________________
Nitrates
Nitrates are one of two critical nutrients (phosphorus is the other) which concern limnologists, since nitrogen is a
fundamental building block of plants and phosphorus is intimately involved in energy transport. Data from the six sites we
monitored showed that nitrate concentrations were moderately high from surface to bottom at all four master stations (2,
3, 8, and 10) in the lake in April, with surface concentrations ranging from 0.27-0.41 mg/L (Fig. 16). At the wetland site
(station 11) nitrates were 0.56 mg/L, while they were even higher at the canal station 12 – 1.12 mg/L (Table 4). These are
very high concentrations of nitrates and depending on how much of this water drains into Pine Lake, could be a
substantial point source of nitrates fueling plant growth in Pine Lake.
18
Figure 16. Nitrates (mg/L) measured in surface waters at six stations sampled on Pine Lake, 15 April 2011.
Interestingly enough, nitrates were very low throughout Pine Lake at all ten stations sampled during August at the
surface as would be expected, since algae and plants remove nitrates for growth (Fig. 17). However, an examination of
the nitrate concentrations with depth revealed that nitrates as noted above were low at the surface, but high at mid depths
at the deeper stations sampled (0.35, 0.36 mg/L at stations 9, 10) (Table 5). Concentrations were low at mid depth and
the bottom at the shallower master station (15-m maximum depth station 2). Lastly, concentrations were also low at the
bottom at the two deep stations. One explanation for this pattern is that algae and aquatic plants removed all the nitrates
from the water prior to stratification at the shallow station 2, accounting for the low conentrations from surface to bottom.
At the two deeper stations nitrates were low at the surface and bottom, but not at mid depth. What may have happened is
that ammonia was produced during anoxic condtions (see ammonia section) at these two deep stations and we find high
concentrations of ammonia on the bottom. When we measured the mid depth concentrations of ammonia, one can see
they are lower than what is on the bottom and that some of the ammonia on the bottom may have been converted to
nitrates at mid depth in the oxygenated water present there prior to maximum stratification. During summer, nitrates at
the wetland were <0.01 mg/L as plants took up all the available nitrates. However, at the canal nitrates were still high as
was found during spring, at levels of 0.67 mg/L (Table 5).
Lastly, Fusilier (2007) showed that prior data for spring nitrates for Pine Lake were in the range of 0.2 mg/L which
is lower than our values, some of which were higher (e.g., 0.5 mg/L at station 8 surface) (Fig. 16). During summer,
previous data confirmed our data; nitrates were very low as was found by Fusilier and he also noted the same
phenonomen that we did of increased nitrates at mid depths, although he offereed no explanation for why. He indicated
that the lake was nitrate limited, suggesting no fertilizers containing either nitrogen or phosphorus should be used on
near-lake areas up to 400 ft from the lake shore, a recommendation we concur with and make for most lakes. Fusilier
also found high concentrations of nitrate in the wetland and canal areas (e.g., 1.12 mg/L).
19
Figure 17. Nitrates (mg/L) measured at the 12 stations sampled on Pine Lake, 15 August 2011. Stations 1-10 are in Pine
Lake, while station 11 is in the wetland and station 12 is in the canal.
Ammonia
Ammonia is another plant nutrient that can help fertilize a lake and is usually produced under anoxic
conditions from decomposition of organic matter on the bottom of lakes during summer; however, it can be produced
elsewhere and flow into the lake via storm drains or canals. It is converted to nitrates in the presence of oxygen. During
spring, among the four master stations we sampled, ammonia ranged from 0.04 to 0.16 mg/L in surface samples (Fig. 18).
Concentrations at station 10 seem to be elevated; remaining stations had low concentrations. Examination of the depth
distribution during spring (Table 4), showed low levels from surface to bottom at three stations, with the exception of the
bottom at station 2 (0.27 mg/L) and the aforementioned high concentrations at station 10 surface (0.16 mg/L).
Concentrations of ammonia in the wetland and canal were both low at <0.06 mg/L.
Figure 18. Ammonia (mg/L) measured at four master stations on Pine Lake and in the wetlands (station 11) and the canal
(station 12), 15 April 2011.
20
During summer, maximum ammonia values in Pine Lake surface samples were all <0.04 mg/L showing uptake by
the plants at this time. Values were somewhat higher at the wetland station 11 (ca. 0.07 mg/l – Fig. 19) and station 12
(canal) where values were at 0.08 mg/L. When the depth distribution of ammonia is examined during summer, it is clear
that ammonia builds up because of decomposition of sediments on the bottom. Ammonia concentrations were around
0.01-0.04 mg/L at the surface, increased to levels around 0.04-0.16 mg/L at mid depths, and were 0.26-0.40 on the
bottom (Table 5). Clearly this is due to stratification during summer which produces anoxia on the bottom which promotes
decomposition products such as ammonia, carbon dioxide, hydrogen sulfide, and phosphorus. These substances will
then be re mixed into the lake during the fall overturn and made available for plant growth in the spring. This is ample
demonstration of one of the sources of fertlization in Pine Lake, over which we have little control, except to curtail organic
input (dead algae and macrophytes) as much as possible by reducing nutrient inputs to the lake. At the wetland and
canal site, ammonia was similar around 0.08 mg/L (Fig. 19).
Figure 19. Ammonia (mg/L) measured at the 12 stations sampled on Pine Lake, 15 August 2011. Stations 1-10 are in
Pine Lake; stations 11 and 12 are in the wetlands and canal respectively.
Soluble Reactive Phosphorus
Soluble reactive phosphorus (SRP) is a measure of the “available” phosphorus in the water that can be utilized by
plants. Total P would be all the P contained in a volume of water including that which is available and that which is tied up
in plants or detritus. SRP values during April at the surface of the four master stations (2, 3, 8, and 10) and the canal and
wetland stations were all <0.01 (Fig. 20). These are very low values and indicate that P is taken up rapidly in the spring,
probably by a diatom bloom we observed in Pine Lake in the spring and by plants and algae in the wetlands and canal.
Examination of the depth distribution of SRP at the four stations revealed a similar low concentration from surface to
bottom (Table 4). SRP was also low at the wetland and canal stations, ca. 0.08 mg/L.
21
Figure 20. Soluble Reactive Phosphorus (SRP) (mg/L) measured at the 6 stations sampled on Pine Lake, 15 April 2011.
Similar findings were observed during the summer where uptake of P is expected to deplete available P to low
levels, which was observed at all Pine Lake stations (Fig. 21). The vertical distribution of SRP at these stations (Table 5)
also showed uniformly low concentrations at all depths and stations. The only station with higher concentrations was
station 12 (canal) which had low concentrations as well (ca. 0.045 mg/L).
Figure 21. Soluble Reactive Phosphorus (SRP) (mg/L) measured at the 12 stations sampled on and around Pine Lake,
15 August 2011. Stations 1-10 are in Pine Lake; stations 11 and 12 are in adjacent wetlands and the canal.
Total Phosphorus/Total Nitrogen
We also measured total phosphorus (TP) and total nitrogen (TN) at stations 10 during April and stations 2 and 10
during August. Concentrations of TP during spring turnover showed low concentrations around 0.01 mg/L from surface to
bottom (Table 6). Most of this P is apparently tied up in diatoms, since concentrations of SRP were also at trace
concentrations at these depths. Values around 0.01 are low, 0.05 is high, and 0.03 mg/L is high enough (if available) to
cause an algal bloom. TN at station 10 was 0.5 mg/L at the surface and mid depth, while it was elevated on the bottom to
0.70 mg/L showing some accumulation there already.
22
In summer we measured these parameters at two stations, 2 and 10. TP was similar at all depths at both
stations, except there were elevated levels at the surface of station 2, probably an accumulation of algae (Table 6). TN
during the summer was elevated on the bottom at both stations to levels ranging from 0.74 to 0.86 mg/L. These are high
levels and show the accumulation of products of decomposition on the bottom. Again, these data show that at least for
nitrogen sources, the sediments in the deep parts of the lake that go anoxic can be sources of nutrients for plant growth in
Pine Lake.
Table 6. Total phosphorus (TP) and total nitrogen (TN) concentrations (mg/L) at master station 10 (surface, mid depth,
and bottom) in Pine Lake, 15 April and master stations 2 and 10 on 15 August 2011. N.A. = not available.
___________________________
STATION
TP
TN
___________________________
15-Apr-11
10S
<0.01
0.50
10M
0.01
0.51
10B
0.01
0.70
15-Aug-11
10S
0.04
N.A.
10M
0.04
0.59
10B
0.06
0.86
2S
0.50
0.50
2M
0.02
0.36
2B
0.06
0.74
____________________________
Secchi Disk Readings
Secchi disk measurements are important data to evaluate long term changes in the lake’s response to nutrients,
developments, plant treatments, new exotic species, or other insults to the ecosystem. They can provide historical
datasets or data from which comparisons can be made or can be used with a year to evaluate how a plant treatment, rain
event, switching to sewers, or chemical spills might impact the water clarity of the lake.
Spring sampling at the three stations we sampled (2, 3, and 8) had secchi disc readings that varied from 4.1 to
4.3 m (13.5-14.1 ft) (Table 7). These are moderate values of water clarity despite the fact that Pine Lake was probably
undergoing a spring algae (diatom) bloom at this time.
During August, secchi disc values were considerably lower
ranging from 2.3 to 3.2 m (7.5-10.5 ft); we attribute these lower values to another algal bloom, since summer values are
usually larger than spring ones in most lakes. Fusilier (2009) found secchi disc readings varied from 28 ft in the spring, to
14 ft in June, to 22 ft in fall during 2008 making our reading of 14 ft in August comparable to his data. His trend data
indicate that secchi disk readings are improving since 2005, which may be attributable to zebra mussels, which filter the
water of algae, increasing water clarity and macrophyte growth.
23
Table 7. Secchi disk (m) values for Pine Lake, 15
April and 15 August, 2011.
__________________________________________
STATION
15-Apr
15-Aug
__________________________________________
1
3.2
2
4.2
3
3
4.3
3.1
4
1.6B
5
3.2
6
2.9
7
2.3
8
4.1
3.1
9
3.2
10
3
_________________________________________
CONCLUSIONS AND RECOMMENDATIONS
Highlights of the study include:
1.
Dissolved oxygen: During summer the lake stratifies with a thermocline around 20 ft; dissolved oxygen was 0.8
mg/L at 30 ft and zero from 46 ft to the bottom at 95 ft. Anoxia produces decomposition products such as
phosphorus and ammonia that can be re distributed to the lake during spring over turn.
2. Conductivity was moderate ranging 679-692 in spring and 621-684 uS/cm in summer. Data from 2011 appears to
be higher than conductivity values found by Fusilier (2009).
3. Chlorides ranged from 80 to 112 in spring and 105 to 111 mg/L in summer. These are moderate values, but do
suggest historical loading of salts into the lake.
4. Nitrates in spring were high, varying from 0.27 to 0.41 mg/L; they were 0.56 and 1.12 in the wetland and canal
respectively. The canal therefore could be a source of nitrates for Pine Lake depending how much of that water
reaches Pine Lake. In summer, nitrates were low on the surface (uptake by plants) and bottom (anoxic- nitrogen
form is ammonia on the bottom), but was elevated at mid depths (ca. 0.36 mg/L), something also noted by
Fusilier. We believe the elevated levels at mid depths is ammonia converted to nitrates before stratification
reached maximum intensity. The canal also had high levels of nitrates (0.67 mg/L) confirming earlier findings.
Lastly, nitrate levels seem to be higher in 2011 when compared to Fusilier’s earlier data.
5. Ammonia in April was elevated at the surface at station 10 and the bottom station 2. Remaining samples were
low. During summer, there was a buildup on the bottom to values around 0.3-0.4 mg/L. As noted, anoxia on the
bottom promotes the buildup of nutrients and act as a source of fertilization of Pine Lake when they get distributed
in the fall turnover.
6. Total Nitrogen was elevated on the bottom in spring (0.7 mg/L) and during summer as well, when values were
0.74-0.86 mg/L on the bottom. Again this stresses the importance of the dead zone in producing nutrients.
7. Water clarity in Pine Lake was 13.5-14.1 ft in spring and 7.5-10.5 ft in summer. The spring values are good, but
the summer values are usually higher and were apparently depressed with an algal bloom. Fusilier found similar
values around 15 ft in June 2008 but higher increases in summer. Overall there has been an increase in water
clarity since 2005, which might be due to zebra mussels filtering algae from the water column.
24
Here are some preliminary recommendations that derive from the results of the study.
1. Nutrient enrichment from the canal: We need to know more about how much water comes from the canal and
drains into Pine Lake. What are observations of residents; if there is no information on this, some efforts to
measure discharge in the spring and after rain storms should be initiated.
2. All of the parameters we measured, detailed sampling at master stations, a dead zone, and excessive algal
blooms and presence of dense macrophytes, especially Eurasian milfoil show that excessive amounts of
nutrients are fueling aquatic plant and algal growth in Pine Lake. There are several sources of nutrients,
including septic tank seepage into the groundwater (from isolated places) and then into the lake,
decomposition of the bottom sediments in the anoxic (dead zone) of the lake during summer and winter, lawn
fertilization and runoff from developed property surrounding the lake, air and rain inputs, geese, and point
source runoff (See item 1).
A. Septic tanks: Any places on Pine Lake that are not on sewers should be to reduce further any potential
inputs from these nutrient sources.
B. Decomposition of sediments in the dead zone: Unfortunately this process is common in all eutrophic
lakes and contributes nutrients to the lake during turnover periods. Only dredging of the offending
sediments will alleviate this problem, but reduction in the nutrient input to the lake will help to slow this
process (see C-F).
C. Lawn fertilization: This could be the silent killer in Pine Lake. One pound of phosphorus can produce 500
pounds of algae and aquatic plants. Most lawns do not need any phosphorus at all, so at a minimum a
rule/recommendation/mandate should be invoked not to use any fertilizer for lawns; failing that at least
mandate that non phosphorus fertilizer be utilized. NO fertilization is best. At times both phosphorus and
nitrogen can cause additional blooms, since both can be limiting. The picture below (Picture 2) shows a
shot of Pine Lake showing extensive lawns, which are green presumably from fertilization and extend all
the way to the lake. No greenbelts are visible. A transformation recognizing the importance of every
riparian home owner to reduce or eliminate fertilizer and plant greenbelts needs to happen. One can see
greenbelts to presumably keep neighbors at bay. Those same greenbelts need to be placed on the
shoreline to keep runoff from penetrating the lake. Particular attention should be paid to the golf course.
The owner/mangers should be approached and asked to use minimum amounts of fertilizers that are only
nitrogen-based. Determine if there are runoff routes that could be controlled with greenbelts.
Minneapolis and Ann Arbor have banned phosphorus in lawn fertilizers after their sewage treatment
plants were violating EPA rules. A recent paper published on the Ann Arbor effort showed that this law
caused a substantial drop in phosphorus both in the sewage treatment plant and in the Huron River.
There are any number of similar examples that show that this is an important step to promote.
D. Non-point source runoff: Here there are many culprits and education is the best remedy. Greenbelts
need to be placed between the lake and the highly developed land adjacent to it. People need to be
cognizant of what they put on the ground around their house: no high phosphate cleaners for the car,
cleanup of pet deposits, no burning of leaves by the lake, etc. Put these recommendations into the
newsletter and herald at annual meetings to garner support.
E. Wet and dry deposition: This is input from the sky and along with acid rain, mercury that has
contaminated our fish, also includes nutrients. Little can be done about this except support for
rules/legislation to clean up coal-burning power plants and other industries that pollute the air.
F. Geese, swans, ducks: Although a minor part of the nutrient budget of a lake, efforts should be made to
reduce the populations of these waterfowl, as they bring in nutrients to the lake.
25
Picture 2. Pine Lake showing extensive green lawns, lack of green belts, and potential for lawn fertilization practices to
pollute the lake.
3.
Invasive Species
You already have three major non-indigenous species in your lake: Eurasian milfoil, starry stonewort, and
zebra mussels. Pine Lake is a popular, all sports lake, with fishing and water skiing prominent sports.
Boats used on the lake could come from all over and may have been in water (especially Great Lakes)
where the veligers of quagga mussels abound (a species you currently do not have and one that is much
worse than zebra mussels). In addition, VHS (viral hemorrhagic septicemia) has recently been found in
Lake St. Clair and other water bodies, which suggests even more strongly that boats visiting Pine Lake
that have been in other potentially contaminated water bodies, be carefully inspected by their owners and
either allowed to dry out or treated with bleach to kill foreign organisms. Live bait from outside the lake,
should be discouraged or banned as well.
LITERATURE CITED
Fusilier, W. 2009. Pine Lake, West Bloomfield Township, Oakland County, 1992-2008. Water Quality Studies. 29 pp.
26