SS3.09 Climate-Lake Interactions
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
 
SegerEM, University of Maine, Orono, USA, Emily.Seger@umit.maine.edu
Webster, K, E, University of Maine, Orono, USA, katherine.webster@maine.edu
Kahl, J, S, University of Maine, Orono, USA, kahl@maine.edu
 
CHEMICAL RESPONSES TO DROUGHT: A COMPARISON OF ACID SENSITIVIE SEEPAGE LAKES IN MAINE AND WISCONSIN
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Due to minimal groundwater and watershed interactions, seepage lakes are a precipitation-sensitive and naturally acidic subset of surface waters. With decreases in acid deposition since the 1980s, seepage lakes in Maine and Wisconsin have shown modest recovery in terms of sulfate-cation ratios. However climate shifts such as drought can influence aquatic chemical trends and recovery from acidification. In Maine, several years of drought occurred in the mid-1980s and 90s, with a severe drought in 2001. In Wisconsin, a severe drought in the latter half of the 1980s bisected a period of higher than normal precipitation. Data from the mid-1980s for 66 seepage lakes in Maine and 30 in Wisconsin show increases in dissolved organic carbon (DOC) and ANC over the entire two decades in both states. However, in drought years DOC tended to be lower depending on groundwater and shoreline wetland influence. Because of seepage lakesí sensitivity to deposition trends rather than watershed inputs, they provide promise as early warning indicators of climate change.