Abstract
Coral skeletons provide unique insights into the geochemistry of the seawater environment in which they calcified. Although these historical archives have been largely accurate, the coral carbon record varies slightly from its seawater environment due to biotic effects and environmental stressors on the coral geochemical record. Flower Garden Banks National Marine Sanctuary is home to Siderastrea siderea, a stony coral species commonly used in paleoclimate studies due to its slow-growing nature. This study analyzes how the S. siderea δ13C record is associated with a variety of biotic factors and environmental stressors, including seawater geochemistry, El Niño-Southern Oscillation (ENSO) events, hurricane years, and recorded coral bleaching and disease. In addition to expanding the S. siderea carbon record to present-day, this study found that photosynthetic processes by the colony’s zooxanthellae symbionts played a large factor in the seasonal cycle of the coral δ13C record, becoming most depleted during peak solar radiation months. This specific colony’s δ13C record did not appear to be associated with reported bleaching events, hurricane years, or ENSO events, although additional coral cores and seawater geochemical data should be collected to compare for intra- and inter-colony differences. By expanding the S. siderea geochemical record to present day and qualitatively investigating which factors influenced the record, it sets the stage for future studies that aim to quantitively determine the geochemical influence of the factors discussed.