Martin Lake and Its Inlets (See Graphs and Tables)

Plant nutrient data gathered from the water column at the middle of Lake Martin showed low concentration of nitrate-nitrogen (0 ppm both on the surface and at 60 cm) for a lake inundated by goose feces, and fairly low concentrations of total phosphorus (0.02 ppm on the surface and 0.04 ppm at 60 cm). These figures, of course, easily comply with FW-2 standards for nitrate-nitrogen and phosphates. It is possible that the high level of photosynthesis permitted by this shallow lake (maximum depth 80 cm), throughout the water column, enhances primary productivity enough that all available N is taken up at the lake’s center, while the same high primary productivity operating near the shore takes up much of the nitrogenous run-off before it reaches the center of the lake. Unfortunately, no nitrate-nitrogen testing was conducted just offshore of where most geese congregate, which would have better characterized the problem.

Regarding physical conditions at mid-lake, turbidity was fairly high (78 FAU at the surface and 87 FAU at 60 cm). Since the samples had a greenish-tint and there was little wind at the time of testing, it is presumed that most suspended particles were phytoplankton. The 24-hour temperature cycle maxima and minima at the mid-lake sampling site diverged quite a bit, from a low at 0400 h of about 24 to 25 degrees C downward 0-60 cm, up to a high at 1800 h of about 30 degrees C throughout the water column. During the daylight hours, temperatures ranged only between 28-30 degrees C (except for a reading at 0930 h of 26.8 degrees C on the surface). This 6 degree C variation greatly exceeds the FW-2 maximum allowable temperature variation of 1.7 degrees C over 24 hours for this parameter, and would be very stressful for most aquatic animals. Equally remarkable is the wide swing in pH over 24 hours, from a low at 0950 h of about 6.5 to 7.4 downward 0–60 cm, up to a high at 1800 h of about 9.6 throughout the water column. While the lowest low reported is just at the FW-2 minimum allowable pH of 6.5, the highest high reported is somewhat above the FW-2 maximum allowable pH of 8.5, and the 3 pH unit 24-hour variation would again be very stressful for most aquatic animals. The parent material of this area’s soils tends to be acidic (high-sulfur clay), with few carbonate inputs, so the large pH swing is entirely consistent with a poorly buffered lake. Notable on the positive side are very high dissolved oxygen levels over the full 24 hours and throughout the water column, well above the FW-2 regulation for DO. Only just before dawn did DO concentrations drop to about 6.8 ppm, with DO concentrations in the range of 8.4-11.1 ppm being the rule after noon-time. It certainly appears that warm, brightly-lit, well-nourished phytoplankton are likely to do what nature intended – release great quantities of oxygen to dissolve at all depths in this shallow lake.

Turning to the R.L. Martin Lake inlets, their nutrient loads (0-0.2 ppm nitrate-nitrogen; 0.04 phosphates), turbidity (5-18 FAU), pH (about 8.2-8.7) and DO (150% saturation) easily met relevant FW-2 standards and are similar to results obtained along the upper reaches of Pond Run discussed earlier. Only high mid-day water temperatures spoiled the picture: the reading for Pond Run water draining into the lake (31.8 degrees C) exceeded the FW-2 maximum, while the minor southern tributary’s temperature reached the maximum allowable 30 degrees C. This latter situation probably exists because the channels are wide, shallow and generally exposed to the sun before entering the lake. Concerning heavy metal concentrations

One of the two benthic macroinvertebrate surveys was conducted at test site # 12, along Pond Run roughly 0.5 miles upstream of the lake, and a "fair" rating resulted. That is, there was "medium" biodiversity, featuring a "moderate" number of common types of very pollution-sensitive and somewhat pollution-sensitive organisms.

Results and Discussion (continue to third part)

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