MERCURY CONCENTRATIONS IN AQUATIC FOOD WEBS OF THE FINGER LAKES, NEW YORK

Contamination of aquatic food webs by mercury (Hg) remains one of the most pressing environmental issues in the northeastern USA. Mercury methylation is a detoxifying mechanism of sulphate reducing bacteria that results in the production of methylmercury, the organic form of Hg that bioaccumulates and biomagnifies in living organisms. The concentration of Hg in top predators is a function of many factors, including the bioavailability of methylmercury, food web structure, and fish growth rate and condition.

The Finger Lakes in western and central New York are a series of glacially formed lakes of varying depths, trophic statuses, and land uses. Fisheries play an important role in making the Finger Lakes regional economic drivers. However, little information is available on Hg biomagnification in the Finger Lakes, and methylmercury concentrations are unavailable for organisms at the base of Finger Lakes food webs. From May – October 2015, we sampled suspended particulate matter, zooplankton, benthos, and fish in five of the Finger Lakes (Honeoye, Canandaigua, Seneca, Cayuga, and Owasco Lakes) on a monthly basis. Fish were targeted from all trophic levels. Here we present total Hg concentrations for fishes in all five lakes, and preliminary data on Hg concentrations in seston, zooplankton, and benthos. We also assess the effect of water quality, including dissolved organic carbon, and land use as predictors of food web Hg concentrations.