Aquatic Sciences Meeting, Albuquerque 2001

SS11 Warm Oligotrophic Waters (Environmental Connections)

Date: Monday, February 12, 2001, Time: 2:30:00 PM

Location: Aztec

Ressler, P, H, Texas A&M University Department of Oceanography, College Station, TX, USA, pressler@ocean.tamu.edu

ACOUSTIC VOLUME BACKSCATTER EVIDENCE FOR LOCALLY ENHANCED STOCKS OF ZOOPLANKTON AND MICRONEKTON IN A CYCLONE LOCATED NEAR THE MOUTH OF THE MISSISSIPPI RIVER

Previous research has shown that the deepwater Gulf of Mexico within approximately 100 km of the Mississippi delta may be preferred habitat for some whales, dolphins, and seabirds due to enriched stocks of their prey. In this presentation, the impact on acoustic volume backscattering strength (Sv) of a sub-mesoscale cyclonic feature centered over the upper continental slope in this region will be examined by comparing two cruises of the Northeastern Gulf of Mexico Chemical and Hydrography Study (NEGOM), a program funded by the U.S. Minerals Management Service (MMS). Data from November 1997 and 1998 document important interannual variability, for a small cyclonic feature present there during November 1997 (but not 1998) corresponded to an area of higher surface chlorophyll and elevated Sv. Sv measured with a 153 kHz acoustic Doppler current profiler (ADCP) has previously shown a positive functional relationship to standing stock biomass measured by zooplankton net systems. Such observations highlight the importance of the variability introduced by small- to meso-scale physical features for zooplankton and micronekton standing stock patterns in the Gulf of Mexico.

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Aquatic Sciences Meeting, Albuquerque 2001

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