HR: 16:30h
AN: OS44B-03    [Abstracts]
TI: Composition and Sources of Suspended Particulate Organic Carbon (POC) in the Ocean Implied by Radiocarbon and Stable Carbon Isotope Ratios of its Organic Fractions
AU: * Hwang, J
EM: jeomshik@uci.edu
AF: University of California, Irvine, Department of Earth System Science, UC Irvine, Irvine, CA 92697 United States
AU: Druffel, E R
EM: edruffel@uci.edu
AF: University of California, Irvine, Department of Earth System Science, UC Irvine, Irvine, CA 92697 United States
AU: Griffin, S
EM: sgriffin@uci.edu
AF: University of California, Irvine, Department of Earth System Science, UC Irvine, Irvine, CA 92697 United States
AB: Suspended particulate organic carbon (POC) is a dynamic carbon pool in the ocean and is expected to exchange carbon with other organic carbon pools such as sinking POC and dissolved organic carbon (DOC). To study carbon cycling through suspended POC, radiocarbon and stable carbon isotope ratios of three organic fractions (extractable lipids, acid-soluble, and acid-insoluble fractions) were measured on samples collected from various depths at an abyssal station (Station M, 220km off the central California coast). Stable carbon isotope ratios of the acid-insoluble fraction were distinctly lower than those of the acid-soluble fraction, but similar to those of the extractable lipids. This trend was persistent throughout the water column. A similar trend was observed for sinking POC from 3450m depth at the same station (Hwang and Druffel, 2003). Radiocarbon isotope ratios of suspended POC are also presented and compared to the results of sinking POC and DOC. Implications of these isotope results on the composition of the acid-insoluble fraction and exchange among the organic carbon pools in the ocean are discussed.
DE: 4805 Biogeochemical cycles (1615)
DE: 4806 Carbon cycling
DE: 4860 Radioactivity and radioisotopes
DE: 4870 Stable isotopes
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting