High School l Undergraduate l Graduate

2007 High School Competition Award

FIRST PLACE

Jennifer Rowe
Bangor High School, Bangor, ME.

Detecting the Presence of Estrogen Receptor Agonists in Maine Lakes
Estrogen receptor agonists (ERAs) present in river water worldwide have been found to cause various reproductive and homeostatic abnormalities in wildlife and are predicted to have adverse affects on humans. However, the presence of ERAs has not, to the knowledge of the writer, been documented in small lakes. In this paper a solid phase extraction (SPE)-gas chromatography(GC)-mass spectrometry(MS) analytical method was used for the determination of estrogen receptor agonists in lake water. Samples from five developed Maine lakes were analyzed for the presence of the natural estrogens estrone (E1), 17b-estradiol (E2) and the synthetic estrogen 17a-ethinylestradiol (EE2). In a water sample from Pushaw Lake, instrumental analysis showed 17b-estradiol (E2) to be present in a concentration of 1.4 ng/L. This is of importance, as research has indicated that low nanogram-per-liter concentrations of the natural and synthetic estrogens cause abnormalities in fish and other wildlife. Also, two samples from Sebasticook Lake appeared to contain 17b-estradiol (E2) but in levels lower than those plotted on the standard curve. These results suggest the presence of sewage water in Pushaw and possibly Sebasticook Lake, either from sewage treatment facilities on their watersheds or faulty septic systems of camps along the lakefront.

2007 Undergraduate Competition Award

FIRST PLACE

Andrew Adelfio, Dylan Harrison-Atlas, Katherine Renwick, David Firmage, Danielle Garneau, and Kirsten Ness
Department of Biology, Colby College, Waterville, ME.

Analysis of Land-Use Patterns in the Long Pond North Watershed and Their Effects on Water Quality
In the fall of 2006, Colby College analyzed land-use and development patterns in the Long Pond North Basin watershed to determine their impact on lake water quality. Recently, the Maine Department of Environmental Protection has observed a decreasing trend in the water quality of Long Pond. The decline observed in dissolved oxygen and transparency may be related to an increasing availability of phosphorus, which is often associated with algal blooms. To quantify the various land-use types found in the Long Pond North watershed, we imported 2003 digital orthophoto quadrangles from the Maine Office of GIS into ArcGIS 9.1. The resulting land-use map was used to determine the phosphorus levels entering Long Pond North from each land-use type. An erosion potential model was created in ArcGIS to highlight areas in the watershed with a high likelihood of erosion, which also contributes to the nutrient loading of the lake. Residential and developed areas, particularly along the shoreline, showed the highest risk of erosion and also represented the highest percent of phosphorous input from any land-use type. Our findings indicate that mixed forests, which contribute little to phosphorus loading and erosion, constitute 85.6 percent of the watershed. However, the potential for shoreline and watershed development, as evidenced by a large number of approved house lots, poses a threat to Long Pond North’s future water quality.

2007 Graduate Competition Award

FIRST PLACE

Dianne Kopec
Dept. of Biological Sciences, University of Maine, Orono, ME.

Mercury Residues in Ingested Harbor Seal (Phoca vitulina) Prey Fish as Evidence for Selective Foraging
Mercury biomagnification in the marine food web increases the mercury concentration in each successive trophic level, yet levels in top trophic predators often exceed expectations based on prey residue levels and predator feeding and assimilation rates. Laboratory studies with mercury-contaminated fish have linked mercury neurotoxicity to behavioral changes associated with reduced predator avoidance.We hypothesized that elevated mercury accumulations in prey increase their vulnerability to predation, thereby increasing mercury body burdens in predators through selective foraging on more contaminated prey.

To test this hypothesis, we analyzed the diet of harbor seals from Mt. Desert Rock, an island located 20 miles offshore in the central Gulf of Maine. Four primary summer prey species were identified and collected using bottom trawls, and hook and line. Mercury residues in wild-caught prey were compared to mercury residues of prey ingested by harbor seals by analyzing undigested fish structures (otoliths and eye lenses) sieved from harbor seal scat. Preliminary data, for Acadian redfish (Sebastes fasciatus), indicate mercury residues in ingested eye lenses were significantly higher than those in eye lenses of wild-caught fish of the same species (P<0.000). A positive relationship (r2=0.69, P=0.005) was found between whole body (16.8 ± 10.7 ng/g wet wt.; mean ± SD) and eye lens (25.1 ± 7.0 ng/g dry wt.) mercury residues in wild-caught redfish; this allowed us to predict whole body mercury in ingested redfish based on mercury residues in ingested eye lenses. Predicted whole fish residues in ingested redfish range between 60 and 650 ng/g wet weight, levels shown to provoke toxic effects in fish.

Preliminary findings of significantly greater mercury residues in ingested redfish support the hypothesis of selective foraging by harbor seals and may help account for their unexpectedly high mercury residues.