Aquatic Sciences Meeting, Albuquerque 2001

SS17 Biogeochemical Dynamics of River-Dominated Margins (Disciplinary and Environmental Connections)

Date: Wednesday, February 14, 2001, Time: 10:45:00 AM

Location: Dona Ana

Goni, M, A, University of South Carolina, Columbia, USA, goni@geol.sc.edu

Yunker, M, B, Institute of Ocean Sciences, Sidney, Canada,

Macdonald, R, W, Institute of Ocean Sciences, Sidney, Canada,

Eglinton, T, I, Woods Hole Oceanographic Institution, Woods Hole, USA, teglinton@whoi.edu

FATE OF ORGANIC MATTER IN THE MACKENZIE RIVER SHELF

Biomarker analyses indicate that continent-derived organic matter dominates the composition of Mackenzie River shelf sediments, accounting for over 60% of the organic carbon in surface sediments. Stable isotope compositions of individual biomarkers and radiocarbon analyses of sedimentary organic carbon reveal that the organic matter delivered by the Mackenzie River is composed of at least three distinct pools. One pool is composed of soil organic matter derived from tundra vegetation in the drainage basin. The remains of freshwater algae originating most likely from lakes in the delta and fossil carbon eroded from the Canadian Cordillera represent the other two pools. Using measurements of the mineral surface area, we investigate the fate or these three continent-derived pools, and of the marine carbon derived from autochthonous productivity, following their deposition on the Mackenzie Shelf. The results of these geochemical analyses are contrasted to previous carbon budgets for the area to better constrain the cycling of organic matter in this river-dominated Arctic margin.

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Aquatic Sciences Meeting, Albuquerque 2001

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