HR: 0800h
AN: OS31A-0551    [Abstracts]
TI: Distribution of chromophoric dissolved organic matter in the North Atlantic: Implications for biogeochemistry and tracer studies
AU: * Nelson, N B
EM: norm@icess.ucsb.edu
AF: Institute for Computational Earth System Science, University of California, Santa Barbara, CA 93106-3060 United States
AU: Siegel, D A
EM: davey@icess.ucsb.edu
AF: Institute for Computational Earth System Science, University of California, Santa Barbara, CA 93106-3060 United States
AU: Carlson, C A
EM: carlson@lifesci.ucsb.edu
AF: Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106
AU: Klamberg, J
EM: jon@icess.ucsb.edu
AF: Institute for Computational Earth System Science, University of California, Santa Barbara, CA 93106-3060 United States
AU: Goldberg, S J
EM: s_goldbe@lifesci.ucsb.edu
AF: Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106
AU: Swan, C
EM: swan@icess.ucsb.edu
AF: Institute for Computational Earth System Science, University of California, Santa Barbara, CA 93106-3060 United States
AB: Chromophoric dissolved organic material (CDOM), the colored fraction of the dissolved organic material (DOM) pool, is a highly dynamic property found throughout the open ocean. Most CDOM found away from continental margins is of open ocean origin and is not derived from riverine input or coastal runoff. CDOM is an optical property; hence, its concentration can be easily detected over large spatial scales using (for example) satellite-borne sensors. Net CDOM production is related to heterotrophic bacterial cycling processes while its losses are due to photobleaching. Vertical distributions of CDOM and in particular its surface signature are therefore regulated by vertical mixing processes in conjunction with these basic CDOM cycling processes. These properties make CDOM a potential ocean circulation tracer whose surface expression can be constrained globally by ocean color data. We are participating in selected CO2/CLIVAR Repeat Hydrography program cruises in order to collect an unprecedented baseline ocean CDOM dataset, to evaluate biological and dynamic processes controlling CDOM, and to evaluate the use of CDOM as an ocean tracer. Initial results from the North Atlantic A16N, A20, and A22 sections show that CDOM abundance (evaluated as optical absorption coefficient) tracks major oceanographic features such as the subtropical mode water and Gulf Stream recirculation. CDOM also has a slight inverse relationship with overall dissolved organic carbon (DOC) concentration. CDOM abundances also appear to correlate to distributions of transient and conserved tracers. These results are consistent with our findings concerning CDOM cycling from our ongoing study at the Bermuda Atlantic Time-series Study (BATS) station, and encourage further application of CDOM to tracer problems.
UR: http://www.icess.ucsb.edu/GlobalCDOM/
DE: 4808 Chemical tracers
DE: 4840 Microbiology
DE: 4847 Optics
DE: 4800 OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL
DE: 1635 Oceans (4203)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting