Southeastern Section - 62nd Annual Meeting (20-21 March 2013)

Paper No. 6
Presentation Time: 10:05 AM


JOHNSON, Claudia C., Geological Sciences, Indiana University, 1001 E. 10th St, Bloomington, IN 47405,

Low diversity reef associations in Puerto Rico and the Caribbean Province during the middle Cretaceous warm period are still an enigma, and as such, allow for investigation of modern counterparts within the region. A multi-year database consisting of corals and seawater allows for investigation of hypotheses regarding the influence of environment on low diversity reefs, ocean acidification, and coral resilience. Seawater samples and coral images were collected from Bonaire National Marine Park (BNMP) on the leeward side of the island in the zone of the now endangered Acropora palmata biofacies. Analytical results indicate elemental values from BNMP are in the general range of global averages at 35ppt salinity for fluorine, bromine, chlorine, calcium, potassium and magnesium. Phosphates, nitrites and nitrates are enhanced at several sites. Measurements of pH taken by colorimetric and indicator strips reveal values of 8.0-8.5 and 8.0, respectively, for all sites all years. After accounting for differences in recruitment surface area, plots of total coral counts represented at sites by collection date indicate the most common corals are Agaricia sp. (100 occurrences), Diploria labrynthiformis (94.6 occurrences), Porites asteroides (36.3 occurrences), Dichocoenia stokesi (22.6 occurrences) and Diploria strigosa (20.8 occurrences). Recruits total 33.6 occurrences and are more abundant in April 2011 than in any previous collection date.

Preliminary analyses of our bioenvironmental inventory confirm low diversity of recruits relative to the adjacent species-rich reefs. Research results discount ocean acidification as a factor influencing low coral diversity. Bleached corals occurred through the 5-year research investigation, but coral resiliency was documented post-bleaching events. Future analyses are directed toward survival times of these low diversity coral associations. With the establishment of long-term ecological monitoring from which empirical data are acquired, we anticipate that results from these bioenvironmental analyses will contribute significantly to scientific discussions regarding rates of biologic change in reef ecosystems, and to the future survival of coral species under conditions of global ocean acidification and increased thermal warming.