HR: 1330h
AN: NB33R-02    [Abstracts]
TI: Young Sub-Arctic Lakes: Are They Valuable as Records of Recent Climate Change?
AU: * Hodgson, J Y
EM: hodgs001@bama.ua.edu
AF: The University of Alabama, Department of Biological Sciences, Tuscaloosa, AL 35487 United States
AU: Ward, A K
EM: award@biology.as.ua.edu
AF: The University of Alabama, Department of Biological Sciences, Tuscaloosa, AL 35487 United States
AU: Ham, N R
EM: nelson.ham@snc.edu
AF: St. Norbert College, Department of Geology, De Pere, WI 54115 United States
AU: Goetz, S L
EM: goetz1sl@cmich.edu
AF: Central Michigan University, Department of Geology, Mount Pleasant, MI 48859 United States
AB: Arctic and sub-arctic regions, which are among the most rapidly warming regions on the planet, are model ecosystems for studying potential impacts of anthropogenic climate change. As the initial part of a larger, multi-regional paleolimnology-climatology project, we measured various features of the lake waters to establish differences among six young and previously unstudied lakes on the Matanuska Glacier, Alaska. Two dystrophic lakes, ~300 yr old, developed atop stagnated, forested ice had high concentrations of dissolved organic carbon (mean 18.7 mg C/L). Two oligotrophic lakes, ~30 yr old, developed atop ice-cored moraines had lower DOC concentrations (mean 3.4 mg C/L). Two ~30 yr old silt-laden, proglacial lakes near the margin had the lowest DOC concentrations (mean 1.1 mg C/L). Nitrate and ammonium concentrations varied across lakes, but were generally higher in the two dystrophic lakes. Zooplankton communities were well established in the dystrophic lakes, but were less abundant or absent in the other lakes. We concluded that the lakes are different in carbon profiles and trophic interactions, which will be beneficial in our paleolimnology study. Changes in carbon isotopes and plankton assemblages stored within the sediments can be used to evaluate the impact of warming in sub-arctic lakes.
DE: 1845 Limnology
DE: 3344 Paleoclimatology
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly