HR: 09:35h
AN: OS51D-07    [Abstracts]
TI: The trace element fingerprint of phytoplankton in ocean particulate matter: positive ID or smudged residue?
AU: * Sherrell, R M
EM: sherrell@imcs.rutgers.edu
AF: IMCS and Dept. Geol. Sci. Rutgers University, 71 Dudley Road, New Brunswick, NJ 08901 United States
AU: Jimonet, A
EM: asjimonet@monmouth.com
AF: IMCS and Dept. Geol. Sci. Rutgers University, 71 Dudley Road, New Brunswick, NJ 08901 United States
AB: The biogeochemical cycles of many trace metals are directly or indirectly driven by the growth, vertical transport, and remineralization of phytoplankton. One of Jack Dymond's research interests was how the geochemical signals of biological processes determine the composition of sinking particulate matter and ultimately the sedimentary record. It seems obvious that there must be links between fundamental aspects of the physiology and biochemistry of phytoplankton growing under a range of oceanic conditions, and the composition of bulk oceanic particulate matter. However, too few attempts have been made to use experimental or observational elemental data to constrain predictions of particulate metal fluxes and their relationship to primary biological processes. On one hand, laboratory-determined metal quotas may suffer from unrealistic species composition and metal availability, and on the other hand attempts to analyze phytoplankton in field samples are typically frustrated by the inability to separate living cells from the abundant organic and inorganic nonliving particles found in most natural waters. Using multi-element analyses of suspended particles in Mid-Atlantic Bight shelf-slope surface waters, and correction factors for non-living particles, we argue that phytoplankton dominate bulk particulate composition for some metals (Zn, Cu, Cd), that non-living particles dominate for other metals (Ti, Fe), and that some metals may fall into either group (Mn, Co). The results show quantitative consistencies with results from diatom lab cultures, and hold promise for improved predictions of vertical metal fluxes associated with carbon export from the euphotic zone of characteristic oceanic regimes.
DE: 4805 Biogeochemical cycles (1615)
DE: 4825 Geochemistry
DE: 4855 Plankton
DE: 4875 Trace elements
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting