SS3.01 Landscape Control of High Latitude Lake and River Ecosystems
Date: Thursday, June 13, 2002
Time: 3:15:00 PM
Location: Carson A
VincentWF, Centre d'Études Nordiques, Laval University, Québec City, Canada,
High latitude limnology encompasses a diverse range of lake types,from ice-based ecosystems to deep lakes in subarctic forest-tundra. The accompanying vegetation gradients affect the organic carbon content and dynamics of the downstream receiving waters that in turn influence aquatic communities and processes. In this study we applied synchronous fluorescence (SF) to characterize the nature of colored dissolved organic matter (CDOM) in a range of high latitude waters. Samples were excited from 200 to 600 nm with a 14-nm offset for the emission beam (as in Belzile et al. 2001. Can. J. Fish. Aquat. Sci. 58: 2405-2418). The fluorescence spectra were compared with fulvic acid standards and lakewater samples from systems dominated by allochthonous terrestrial inputs versus autochthonous, in situ production. Waters in two polar regions were examined: Northern Ellesmere Island in the Canadian High Arctic (lat. 83 N) and Byers Peninsula in maritime Antarctica (lat. 62 S). SF analysis gave a better separation of lakewaters than other spectrofluorescence assays of CDOM and appears to be a useful approach towards characterizing land-water coupling across a broad range of ecosystem types.