HR: 11:20h
AN: B42A-04    [Abstracts]
TI: The Presence and Export of Labile Dissolved Organic Matter from Glacier Systems
AU: * Barker, J D
EM: barker.246@osu.edu
AF: Byrd Polar Research Center, Rm 109 Scott Hall, 1090 Carmack Road The Ohio State University, Columbus, OH 43210, United States
AU: Chin, Y
EM: yo@geology.ohio-state.edu
AF: Byrd Polar Research Center, Rm 109 Scott Hall, 1090 Carmack Road The Ohio State University, Columbus, OH 43210, United States
AU: Sharp, M J
EM: martin.sharp@ualberta.ca
AF: Dept. Earth and Atmospheric Sciences, 1-26 Earth Sciences Building University of Alberta, Edmonton, AB T6G 2E3, Canada
AU: Lyons, W B
EM: lyons.142@osu.edu
AF: Byrd Polar Research Center, Rm 109 Scott Hall, 1090 Carmack Road The Ohio State University, Columbus, OH 43210, United States
AU: Turner, R J
EM: turnerr@ucalgary.ca
AF: Dept. Biological Sciences, 156 Biological Sciences Building University of Calgary, Calgary, AB T2N 1N4, Canada
AB: Glaciers are the source for many important rivers globally. Increased rates of glacier melt in response to climate warming result in an increased flux of glacially-derived organic material to downstream aquatic ecosystems. This is particularly true in polar regions where glaciers are most abundant and climate warming is most significant. Dissolved OM (DOM) is a significant factor in aquatic biogeochemical processes and its characteristics may exert a fundamental influence of downstream aquatic ecological processes. There have been few studies of DOM export from glacier systems and questions remain regarding the characteristics of glacially derived OM and its biogeochemical behavior in downstream aquatic ecosystems. We studied the characteristics of DOM in three glacier systems using fluorescence spectroscopy (in both synchronous and emission-excitation modes) and analyzed the spectra using principal components (PCA) and parallel factor analyses (PARAFAC). These systems have potentially different OM sources due to their locations. Outre Glacier is an alpine glacier in the Coast Mountains of British Columbia, Canada, John Evans Glacier is a valley glacier in arctic Canada, and Canada Glacier is a valley glacier in the McMurdo Dry Valleys, Antarctica. We collected supraglacial snow, glacier ice and proglacial meltwater and its resident DOM was characterized. All of the supraglacial snow and glacier ice samples exhibit DOM with a common and dominant fluorophore, which we tentatively attribute to a "tyrosine-like" component. The presence of this component does not persist in proglacial streams and is replaced by fluorophores which are indicative of possible "tryptophan-like" and humic components in the DOM. The export of the "tyrosine-like" component from glaciers and its disappearance in proglacial streams may be indicative of biogeochemical processing in proglacial streams and therefore may function as an important initial substrate for microbial metabolism in glacier-fed streams.
DE: 0428 Carbon cycling (4806)
DE: 0475 Permafrost, cryosphere, and high-latitude processes (0702, 0716)
DE: 0736 Snow (1827, 1863)
DE: 0744 Rivers (0483, 1856)
DE: 0793 Biogeochemistry (0412, 0414, 1615, 4805, 4912)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting