Aquatic Sciences Meeting, Albuquerque 2001

SS06 Carbon Fluxes at Ocean and Large Lake Margins (Environmental Connections)

Date: Friday, February 16, 2001, Time: 10:00:00 AM

Location: Cochiti/Taos

Chen, R, F, UMassBoston, Boston, USA, bob.chen@umb.edu

Zhang, Y, , UMassBoston, Boston, USA, g5728yzhan@umbsky.cc.umb.edu

Rudnick, S, M, UMassBoston, Boston, USA, steven.rudnick@umb.edu

THE FLUORESCENCE OF DISSOLVED ORGANIC MATTER IN THE MID-ATLANTIC BIGHT

As part of the Ocean Margins Program supported by the Department of Energy, we have measured the fluorescence of dissolved organic matter extensively throughout the Mid-Atlantic Bight. Samples were collected on three whole shelf cruises (RV Iselin, April, 1994; RV Endeavor, March, 1996; RV Seward Johnson, August, 1996). A subsequent cruise in the Chesapeake and Delaware Bays (RV Cape Henlopen, August, 1998) allowed us to explore the terrestrial/estuarine source of fluorescent dissolved organic matter to the Shelf. Additionally, continuous surface measurements were made using time-resolved laser-induced fluorescence spectroscopy of flowing seawater and detailed vertical profiles were made with an in situ fluorometer. In situ and discrete measurements of fluorescence intensity, fluorescence spectrum (excitation and emission), and fluorescence lifetimes suggest the fluorescent fraction of dissolved organic matter behaves conservatively throughout the estuaries and is delivered more or less intact to the shelf. Once on the shelf, an additional source from biological processes as well as a sink due to photodegradation are apparent in some areas at certain times. A mass balance approach to fluorescence sources and sinks will be discussed.

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Aquatic Sciences Meeting, Albuquerque 2001

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