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PERIPHYTON AND SEDIMENT BIOASSESSMENT IN NORTH FLORIDA BAY
Citation:
Lewis, M A., D. E. Weber, AND R S. Stanley. PERIPHYTON AND SEDIMENT BIOASSESSMENT IN NORTH FLORIDA BAY. Presented at 1999 Florida Bay Conference, Key Largo, FL, November 1-5, 1999.
Description:
Periphyton colonization and sediment bioassessment were used in a survey to determine the relative environmental condition of multiple sampling sites located in Florida Bay and four peripheral slough areas during the summer of 1995. The primary focus of the study was to provide much-needed information on sediment toxicity, since its magnitude and extent in the Florida Bay/Everglades transitional area are almost unknown. Periphyton biomass, pigment content, tissue quality and community composition were determined. In addition, benthic community composition and toxicities of whole sediments and associated pore waters were determined using two species of rooted macrophytes (Spartina alterniflora, Scirpus robustus), an epibenthic invertebrate (Mysidopsis bahia) and bioluminescent bacteria. Several locational differences were observed in the survey for the response parameters. Periphyton biomass was significantly greater in the Taylor River and the least in Shell Creek (P = 0.05). Most whole sediments were not acutely toxic to mysid shrimp. The maximum level of mortality observed for the benthic invertebrate in the contaminated sediment was 20% above that observed for the reference sediment. The sediments were not phytoinhibitory but those collected from the Taylor River were 2 to 3 times more phytostimulatory than others (P = 0.05), based on ash free dry weight. Contaminant residues in the periphyton were similar at most sites; however, mercury, chromium and nickel concentrations were greater for periphyton colonized in the Taylor River and Trout Creek areas. Structural characteristics of the periphytic algal community usually were statistically similar (P = 0.05) but a consistent trend of lower density and diversity was evident for Shell Creek. The benthic community was the least diverse and dense in the Canal C-111. The results of this study provide an initial indication of differences in the role of several slough areas as possible sources of bioavailable contaminant