Investigating Algal Symbionts in Corals From St. Lucie Reef, Florida

Algal symbionts, commonly called zooxanthellae, living in within coral tissues provide
energy to hermatypic corals through photosynthesis. Zooxanthellae density, as well as
photosynthetic pigment concentration, can be used as an indicator of coral health. This study compared zooxanthellae densities and concentrations of chlorophyll a and c between four sites and two species of coral, Montastraea cavemosa and Diploria clivosa, found at the St. Lucie Reef to establish baseline levels for comparison to future levels. No significant differences were found among sites despite increasing depth farther from the inlet, suggesting reduced light penetration closer to the inlet. Significant differences were found for zooxanthellae densities and chlorophyll concentrations per zooxanthellae cell between coral species. However, there was no significant difference for chlorophyll concentrations per unit area of coral tissue between species. This suggests that all site locations experience similar conditions despite differences in depth. It also suggests potentially different types of zooxanthellae, which is being addressed by ongoing research.