You are here:
PHYTOPLANKTON-AND DETRITUS-BASED FOOD WEBS IN GULF OF MEXICO ESTUARIERS: LESSONS FROM PENSACOLA BAY FL, USA
Citation:
Murrell, M C., J. Hagy, J.D., III, R M. Greene, AND J B. James. PHYTOPLANKTON-AND DETRITUS-BASED FOOD WEBS IN GULF OF MEXICO ESTUARIERS: LESSONS FROM PENSACOLA BAY FL, USA. Presented at Estuarine Research Federation Conference, Seattle, WA, Sep 14-18, 2003.
Description:
A central theme in estuarine ecology is understanding the connection between riverine delivery of nutrients and organic matter and how these materials are processed within the estuary. Key to this understanding is the ability to quantify the importance of detrital carbon in supporting estuarine food webs. Our focus has been Pensacola Bay, a sub-tropical estuary in the northeastern Gulf of Mexico. One approach we employed was to compare the biomass and production of major plankton groups with the freshwater flux of organic matter. The potential for riverine TOC to support bacterioplankton production appears quite small; the average TOC flux of 70 mg C/m2/d represents only 17% of estimated bacterioplankton production. Adjusting for bacterial growth efficiency and refractory TOC pools further reduces the potential contribution of riverine TOC. A simple budget of particulate carbon is partitioned as follows: 39% phytoplankton, 13% bacterioplankton, 5% zooplankton, and 42% detritus. These analyses suggest that the Pensacola Bay food web is largely supported by autochthonous primary production. Several characteristics distinguish Gulf of Mexico estuaries from better-studied temperate estuaries, including temperature regime, tidal energy, depth, and the role of episodic events. We plan to discuss how these characteristics might affect the relative importance of phytoplankton and detritus in estuarine food webs.