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UPWELLING EVENT IN THE DRY TORTUGAS DURING MAY 1998
Citation:
Santavy, D L., L. G. MacLaughlin, J. W. Porter, J G. Campbell, R L. Quarles, AND M. Parsons. UPWELLING EVENT IN THE DRY TORTUGAS DURING MAY 1998. Presented at International Conference on Scientific Aspects of Coral Reef Assessment, Monitoring, and Restoration, Fort Lauderdale, FL, April 14-16, 1999.
Description:
A major macro-algae bloom was observed during a coral disease survey in May 1998 in the Dry Tortugas and New Grounds region. The significant algal growth was found only on the outer slope of reefs in depths greater than 25'; the algal bloom was not present on shallow reefs. The algal growth was so deep that it covered large Montastraea faveolata colonies and was over a meter deep in spur or depression areas of the reef surface. Samples of the algae were collected and the primary constituent was identified as Cladophora sp. The different water masses were sampled employing CTD profiles and deployable water quality monitors to measure water quality parameters. Measurements revealed that the deeper water masses, associated with the macro-algae blooms, had significantly higher salinities, lower temperatures, higher nutrient contents, and higher chlorophyll concentrations than the surface water and water in shallower reef areas. The vertical stratification of the algal growth and different water characteristics observed by SCUBA surveyors, strongly suggested that an upwelling event was occurring. Corals covered by the algal mat were beginning to bleach at the time of the survey. The algae covered coral for several weeks, but permanent damage was not apparent when the reefs were observed again during the September disease survey. This event occurred during the same time that significant macro-algae blooms were observed throught the Florida Keys, and decreased sea-surface temperatures were observed in many coastal regions throughout the Gulf of Mexico.