MWC 2006 SPONSORS: U.S. Geological Survey • Senator George J. Mitchell Center for Environmental and Watershed Research • Maine Drinking Water Program, Dept. of Health & Human Services • Portland Water District • Aqua Maine • Maine Dept. of Environmental Protection • Maine Geological Survey • Maine Coastal Program, State Planning Office • Maine Rural Water Association • Maine Wastewater Control Association • Maine Water Utilities Association • Maine Congress of Lake Associations • Maine Volunteer Lake Monitoring Program • UMaine Cooperative Extension

High School l Undergraduate l Graduate

2006 High School Competition Award

FIRST PLACE

Chloe Shields and Robert O’Neill (advisor)
Greely High School, 303 Main Street, Cumberland, ME 04021; 207/829-4805; robert_o'neill@msad51.org.

A TROPHIC STUDY OF LAKE ENVIRONMENTS AND SOIL ECOLOGY
The basis for this study came from analysis of the effects of nutrient runoff into a water source. Phosphorus, a common nutrient, can lead to over-fertilization due to increased phytoplankton. Three lakes were selected for testing, each with differences in trophic state and surrounding environmental development, to determine the effects of sediment runoff on the production of phytoplankton. Soil samples near common usage areas around three lakes, each with environmental differences, were washed with distilled water and runoff was filtered, so nutrients were contained in an aqueous solution. Lake water was added, naturally containing both phosphorus and phytoplankton. These samples were incubated to produce phytoplankton and compared through location, phytoplankton growth and environmental condition. Nutrient content in soil was inferred based on growth measured in percent absorbance via spectrophotometer, finding that nutrient content increased as distance from the water source lengthened. Variations in growth and nutrient content were seen throughout the diversity of the environments tested. Soil samples were further analyzed through dilution of bacteria to quantify the density of a 1mL microbial sample, finding higher nutrient levels generally containing greater microbial density. These results allowed for speculation into environmental quality and trophic state through phytoplankton growth, nutrient content and trends in microbial density.

2006 Undergraduate Competition Award

FIRST PLACE

Sharon McMonagle, Bethany Peck, F. Russell Cole¹, David H. Firmage², and Kirsten L. Ness
Department of Biology, Colby College, Waterville, ME 04901.
¹207/859-5728; frcole@colby.edu.
²207/859-5730; dhfirmag@colby.edu.

LAKE WATER QUALITY ANALYSIS AND POSSIBLE REMEDIATION TECHNIQUES FOR CHINA LAKE, KENNEBEC COUNTY, MAINE
Colby College conducted an assessment of water quality and relevant watershed characteristics of China Lake, Kennebec County, Maine during the summer and fall of 2005. Physical and chemical parameters were analyzed to determine lake water quality. Algal blooms have been a problem in China Lake, a eutrophic lake, for over 20 years. Mean epicore phosphorus levels were approximately 17 ppb during the fall of 2005, slightly higher than the 15 ppb threshold for algal blooms. With the exception of 1985 and 1990, fall surface phosphorus levels have been above 15 ppb in every year since 1984. During the 2005 samplings, hypolimnetic phosphorus levels were as high as 200 ppb. The mean transparency in the summer and fall of 2005 was 2.90 ± 0.40 m and in August and September 2005 there was a sharp decline in dissolved oxygen below 10.0 m. Potentially anoxic waters cover 44.8% of the sediment in China Lake during the summer. Anoxic conditions increase internal nutrient loading, which was calculated to contribute 46% of the total phosphorus load to the lake. Maintenance of camp roads, buffer strips, and septic systems is important to reduce external phosphorus loading. However, to successfully reduce phosphorus levels, in-lake remediation techniques, such as alum treatment, should be considered.

2006 Graduate Competition Award

FIRST PLACE

Tara R. Trinko¹, Katherine E. Webster¹, David B. Halliwell², and Jennifer Kray^1
1Dept. of Biological Sciences, University of Maine, 5751 Murray Hall, Orono, Maine 04469; 207/581-2574; tara.trinko@umit.maine.edu; katherine.webster@umit.maine; jennifer.kray@umit.maine.edu.
²Maine Department of Environmental Protection, 17 State House Station, Augusta, ME 04333; 207/287-7649; david.halliwell@maine.gov.

THE EFFECTS OF JUVENILE WHITE PERCH PREDATION ON ZOOPLANKTON GRAZERS IN TWO SHALLOW EUTROPHIC LAKES WITH CONTRASTING ALGAL BLOOM FREQUENCIES
Understanding the trophic relationships among phytoplankton, zooplankton and planktivorous fish is especially important when evaluating causes of nuisance algal blooms in eutrophic lakes. Two connected shallow eutrophic lakes in central Maine differ substantially in their algal bloom frequency. Nuisance algal blooms have occurred in the upstream East Pond (695 ha) seven of the past 10 years, but not in the downstream North Pond (1024 ha). Based on spring mark-recapture estimates, East Pond has roughly twice the white perch population of North Pond, suggesting that top-down pressures from juvenile white perch may be controlling zooplankton grazers and exacerbating blooms. We compared juvenile white perch diet composition to in-lake zooplankton community structure to assess the relative influence of planktivory on zooplankton population dynamics over two open-water seasons. Cladoceran body size was larger in juvenile stomachs compared to in-lake conditions in both lakes. In addition, average in-lake cladoceran body size was larger in North Pond. These findings support our hypothesis that higher planktivory rates are contributing to the nuisance algal blooms in East Pond.