HR: 14:35h
AN: OS52F-03    [PDF]
TI: Carbon Preservation in Differing Fjord Environments: Tracking the Origin and Fate of Marine and Terrestrial Organic Matter
AU: * Nuwer, J M
EM: jnuwer@u.washington.edu
AF: University of Washington, School of Oceanography, Ocean Science Bldg 355351, Seattle, WA 98105 United States
AU: Keil, R G
EM: rickkeil@u.washington.edu
AF: University of Washington, School of Oceanography, Ocean Science Bldg 355351, Seattle, WA 98105 United States
AB: Factors believed to influence the amount of organic carbon preserved in marine sediments include the organic matter's origin, surface area of the associated minerals, and oxygen exposure time. This study addresses where, under what conditions, and by what mechanism both marine and terrestrial organic matter are preserved in Clayoquot Sound. Located on the southwestern coast of British Columbia's Vancouver Island, Clayoquot Sound is a series of interconnected fjords where normal estuarine mixing is hindered by the presence of glacially formed sills, causing distinct depositional environments to exist over a short geographic distance. Heavy liquid floatation was used to isolate organic debris from mineral-associated organic matter for soil, riverbed sediment, and marine sediment. These fractions were then evaluated using bulk analyses, stable carbon isotopes, and mineral surface area measurements. The evolution of mineral-associated organic matter can be traced as the minerals pass through the watershed and are ultimately deposited in the fjord. This mineral-associated organic carbon is almost entirely marine derived, while terrestrial carbon is preserved mainly as sedimentary organic debris. The mineral-associated organic matter fraction displays excessive organic carbon to surface area ratios at sites influenced by anoxic bottom water.
DE: 3022 Marine sediments--processes and transport
DE: 4850 Organic marine chemistry
SC: Ocean Sciences [OS]
MN: 2004 Ocean Sciences Meeting