Aquatic Sciences Meeting, Albuquerque 2001

CS40 Nutrients, Primary Production, and Aquatic Ecosystems

Date: Wednesday, February 14, 2001, Time: 4:00:00 PM

Location: La Cienega

Currin, C, A, NOS/NOAA, Beaufort, USA, carolyn.currin@noaa.gov

Burke, J, S, NOS/NOAA, Beaufort, USA, john.burke@noaa.gov

Fonseca, M, S, NOS/NOAA, Beaufort, USA, mark.fonseca@noaa.gov

Kenworthy, W, J, NOS/NOAA, Beaufort, USA,

Macko, S, , University of Virginia, Charlottesville, USA,

Hall, M, O, Florida Marine Research Institute, St. Petersburg, USA,

SOURCES OF PRIMARY PRODUCTION SUPPORTING THE FOOD WEB AT MODERATE DEPTHS ON THE WEST FLORIDA SHELF

The seafloor on the West Florida Shelf is a habitat mosaic composed of open sand areas, Halophila decipiens beds, and live bottom. In a series of cruises in 1999, we sampled primary producers, benthic invertebrates and fish at stations ranging from 12 to 30 m depth. Microalgal biomass in the top 2 cm of the sediment exceeded depth-integrated phytoplankton biomass at each station and sampling time. Seagrass and macroalgal biomass were patchily distributed, with peaks in biomass occurring at shallower stations and late summer. Benthic invertebrates, particularly shrimp, had isotopic signatures indicating utilization of Halophila production. Fishes also demonstrated a reliance on benthic production, including benthic species (flatfish, catfish) which had isotopic signatures indicating a benthic algal-based food web, but also pelagic planktivores (sardines) and predators (jacks and scombrids). Our results support the hypothesis that benthic primary production provides the base for the food web on this portion of the West Florida Shelf, and that high levels of fishery production associated with the live bottom habitats are in fact directly supported by the surrounding open sand, algae and Halophila communities.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

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