CORALS
GROUNDTRUTHING NITROGEN ISOTOPES AS A SYMBIOSIS PROXY USING THE FACULTATIVELY SYMBIOTIC CORAL OCULINA ARBUSCULA
Coral reefs thrive in nutrient-poor tropical oceans because of the symbiotic partnership between corals and their algal symbionts, which efficiently recycle nutrients. This project tested whether nitrogen isotopes preserved in coral skeletons can be used to identify the presence of this symbiosis in corals. Using laboratory experiments with genetically identical symbiotic and aposymbiotic corals, we showed that symbiotic corals consistently have lower nitrogen isotope values due to internal nutrient recycling. These results strengthen the use of coral nitrogen isotopes as a tool for reconstructing the evolutionary history of coral-algal symbiosis and understanding how this relationship has shaped reef ecosystems through time. Read more about it here!
ELUCIDATING BIOLOGICAL CONTROLS ON CORAL NITROGEN ISOTOPES IN AN OLIGOTROPHIC CARIBBEAN REEF
Coral skeletons preserve nitrogen isotope records that can reveal both reef nitrogen cycling and the relationship between coral hosts and their symbiotic algae. In this project, I measured nitrogen isotopes across 16 coral species from Bocas del Toro, Panama, and compared them with seawater nutrients, plankton, coral morphology, and symbiont communities. These findings will improve our understanding of how biological processes influence coral nitrogen isotope records and provide a framework for selecting the best coral species for reconstructing past marine nitrogen cycling and reef ecosystem change.
ISOTOPIC CONSTRAINTS ON THE FATE OF ANTHROPOGENIC NITROGEN IN THE NORTHERN GULF OF MEXICO
Human activities have greatly increased the amount of nitrogen entering coastal oceans, contributing to water quality degradation and ecosystem change. This project investigates whether nitrogen delivered by the Mississippi-Atchafalaya River Basin reaches the open Gulf of Mexico or is removed before it can spread offshore. By combining seawater and coral nitrogen isotope records with a high-resolution coupled physical-biogeochemical ocean model, this research examines the transport and cycling of anthropogenic nitrogen across the Gulf of Mexico and improves our understanding of how coastal processes influence offshore marine ecosystems.
