Aquatic Sciences Meeting, Albuquerque 2001

SS17 Biogeochemical Dynamics of River-Dominated Margins (Disciplinary and Environmental Connections)

Date: Wednesday, February 14, 2001, Time: 12:15:00 PM

Location: Dona Ana

Gardner, B, , University of Massachusetts Boston, ECOS, Boston, MA, USA, bernie.gardner@umb.edu

Chen, R, F, University of Massachusetts Boston, ECOS, Boston, MA, USA, bob.chen@umb.edu

HIGH RESOLUTION MEASUREMENTS OF CHROMOPHORIC DISSOLVED ORGANIC MATTER (CDOM) IN THE MISSISSIPPI RIVER PLUME

A towed, undulating vehicle (the ECOShuttle) developed at the University of Massachusetts Boston was deployed in the Mississippi River Plume in June, 2000. Instruments incorporated in the ECOShuttle provided fluorescence of CDOM, petroleum hydrocarbons and chlorophyll as well as dissolved oxygen and optical backscatter. The vehicle also carried a pump, which delivered 8 liters/minute of seawater to shipboard instruments and sampling ports. A detailed distribution of the low salinity plume as well as CDOM associated with this plume as it extends into the Gulf of Mexico will be presented. The relationship between CDOM and salinity within the Mississippi River and in the Plume showed an approximately conservative mixing process within the surface layer with evidence of photodegradation as the plume water ages. Distinct properties are noted for the Mississippi water, water from adjacent marshes, and from the Atchafalaya River. In the Gulf below the plume, patches of high CDOM were observed coincident with elevated chlorophyll concentrations, indicative of local biological generation of CDOM. Optical characteristics of these distinct sources of CDOM will be discussed.

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Aquatic Sciences Meeting, Albuquerque 2001

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