Assessing the Health of Coral Reef Ecosystems in the Florida Keys at Community, Individual, and Cellular Scales

Coral reefs are threatened in Florida and worldwide. Successful resource management requires rapid identification of anthropogenic sources of stress before they affect the reef community. I tested a multi-scale approach for assessing reef condition at seven reefs within the Florida Keys National Marine Sanctuary and Biscayne National Park between 2001 and 2003. I examined multiple environmental parameters to identify potential sources of stress. I utilized the Atlantic and Gulf Rapid Reef Assessment Biotic Reef Index to assess benthic community structure and an indicator species of Foraminifera (Amphistegina gibbosa) to determine if environmental conditions were suitable for calcareous organisms that host algal endosymbionts. Small tissue samples were extracted from colonies of Montastraea annularis species complex to assay a suite of cellular biomarkers to elucidate possible mechanisms of the coral stress response. I monitored regeneration rates of the resultant lesions to determine if the coral colonies were capable of recovering from damage. Multivariate data analyses indicated that corals at all study sites were experiencing stress with different degrees of response and decline. On reefs with coarse grain sediments that are adjacent to an intact mangrove shoreline, the Cellular Diagnostic System indicated that corals were responding to a xenobiotic stress but appeared to be compensating as evidenced by consistently high lesion regeneration rates, a high percentage of healed lesions, low coral mortality and high abundances of A. gibbosa. On reefs with silt-sized sediments adjacent to developed coastlines, corals also were responding to xenobiotic stresses, but were negatively affected as evidenced by low regeneration rates, a low percentage of healed lesions, high coral mortality, and low abundances of A. gibbosa. Corals at an 18 m offshore site exhibited abnormally low biomarker levels and some died during the study, indicating that sampled colonies were incapable of upregulating necessary protective proteins. Further research will be required to determine stressor sources. This study demonstrates that a multiple-indicator approach, spanning scales from cellular to community, can provide marine resource managers with data linking decline of coral populations to specific environmental conditions and events, thereby providing potential for early detection of stressors allowing for preventive management