Plankton Indicators of Ecological change in Southern Biscayne Bay, Final Report

Brand, Larry

The Comprehensive Everglades Restoration Plan (CERP) is expected to alter land runoff into southern Biscayne Bay, altering its salinity and nutrient regimes and other aspects of the ecosystem. Because this is such a large, unprecedented project that will alter the entire South Florida hydroscape, it is recognized that all of the ecological consequences cannot be predicted ahead of time. As a result, the strategy of adaptive management will be used to observe changes in various ecosystems so that midcourse corrections can be made. Therefore, baseline studies need to be conducted before hydrographic alterations begin. Also, specific indicators of environmental stress are needed for long term monitoring. Phytoplankton are among the most sensitive indicators of water quality and ecosystem health. Because of pelagic-benthic coupling in shallow ecosystems like Biscayne Bay, changes in phytoplankton would reflect not only changes in land runoff directly, but also changes in the sediments and shallow benthic community as a result· of changes in land runoff. Because of the expense of long term monitoring, only techniques that are relatively simple, quick, and inexpensive are very useful. several specific indicator ratios of environmental stress in the phytoplankton community were examined for their use in monitoring ecosystem health. As a broad generalization, phycocyanin-rich cyanobacterla and chlorophyte phytoplankton (e.g. green algae, euglenids) tend to become dominant in stressed marine ecosystems, and chromophyte phytoplankton (e.g. diatoms, dinoflagellates) dominate in stable marine ecosystems. It was hypothesized that, as a result, the ratios of phycocyanin:chlorophyll a and chlorophyll b:chlorophyll a could be used as indicators of stress on the phytoplankton

Plankton Indicators of Ecological change in Southern Biscayne Bay, Final Report

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