Significant increases in nutrient concentrations have been observed in a number of natural reef systems over the last several decades. Elevated nutrient levels adversely affect coral growth rates and are regarded as a key "switch-off" factor in reef development. Thus, the trend of increasing coastal nutrification demands further investigation. Recent advances in molecular biotechnology have developed an integrated cellular diagnostic system (EDCS), which utilizes enzymatic biomarkers to assess the physiological status of corals. This tool, in concert with histopathology can allow identification of environmental stress before the effects become significant, providing a major step forward in the investigation and management of worldwide coral reef degradation. The primary objective of this study is to verify that histopathology coupled with ECDS effectively detects environmental stress in a controlled laboratory environment.
Thirty-two specimens of Montastraea cavernosa will be maintained in the laboratory under four experimental conditions: control, nitrate enrichment, phosphate enrichment, and combined nitrate-phosphate enrichment. Initial nutrient concentrations will be 5 m m NO 3 - and 2 m m P-PO 4 3-. After two weeks, half of the corals will be preserved for histopathological and biomarker analysis. Subsequently, nutrient levels will be increased to 10 m m NO 3 - and 4 m m P-PO 4 3- for two weeks, after which all remaining corals will be preserved for further analysis. Cell damage and/or failure to function adequately will be histologically assessed based on tissue condition of the coral upper epidermis, oral disk, mesenteries and lower gastrodermis. Additionally, a suite of enzymatic biomarkers will be assayed to evaluate cellular physiologic condition and stress responses (i.e., oxidative stress, protein metabolic condition, endocrine modulation). Parametric and non-parametric statistics will test differences among treatments.
Several lectures conducted in collaboration with the University School science program will address coral reef ecology, status, and research efforts. Students will also visit the Oceanographic Center, where hands-on participation will be encouraged.