Seasonal and vertical variability in the mercury speciation of an acidified Wisconsin lake.
Mercury speciation data were collected from August 1988 through February 1989 at several depths in an experimentally acidified lake in northern Wisconsin. During stratification, methylmercury (CH3HgX) levels of about 0.25 pM and total mercury (Hgt) levels of 6 pM were observed in the upper water column. Concentrations increased with depth to 20 pM CH3HgX and 55 pM Hgt in the oxygen-depleted bottom waters. Following mixis, the water column attained unifonn levels of about 0.13 pM CH3HgX, and 2.5 pM Hgt. The results emphasize the importance of hypolimnetic processes to the biogeochemistry of mercury in lakes.
2 Edinburgh: CEP Consultants.