Title: Corals on Acid - Ocean acidification impacts on Coral Reefs
Abstract: Rising atmospheric CO2 and its equilibration with surface ocean seawater is lowering both ocean pH and ocean carbonate saturation state. Numerous calcifying organisms, including reef-building corals, may be severely impacted by declining aragonite and calcite saturation, but the fate of coral reef ecosystems in response to ocean acidification remains largely unexplored. Naturally low saturation groundwater has been discharging for millennia at localized submarine springs (called “ojos”) at Puerto Morelos, México near the Mesoamerican Reef. This ecosystem provides insights into potential long term responses of coral ecosystems to low saturation conditions. In-situ chemical and biological data indicate that certain coral species grow at low pH conditions however both coral species richness and coral colony size decline with increasing proximity to low-saturation, low-pH waters. Transplantation experiments indicate that the potential for acclimation is uniform but is manifested differently by each of the species investigated.The results suggest that efforts have to be implemented to protect corals from other stressors so they may be able to overcome the negative effects of lower aragonite saturation.