Project: Collaborative Research: Identifying the Role of Basin-scale Climate Variability in the Decline of Atlantic Corals

Text from the NSF award abstract:

Human carbon dioxide emissions are causing measureable changes in ocean conditions. Many of these changes negatively affect coral reef ecosystems, reducing their ability to provide food, arable land, tourist destinations and coastline protection for hundreds of millions of people worldwide. This project focuses on the effects of enhanced stratification, caused by ocean warming, on the growth of reef-building corals across the Caribbean and Bermuda. Enhanced stratification impacts primary productivity which generates food for corals. Initial data generated by the investigators suggest that Atlantic coral growth has declined in the last 5 decades in response to these changes. A laboratory-based experiment is designed to test this hypothesis. If verified, the projected decline in Atlantic primary productivity through the 21st century could potentially rival and will certainly exacerbate the effects of warming and ocean acidification on coral reef ecosystems across the North Atlantic. Support is provided for graduate research, and undergraduate participation is facilitated through the Woods Hole Oceanographic Institution Summer Fellowship and the Bermuda Institute of Ocean Sciences-Princeton Environmental Institute Summer Internship Programs. The results will be presented at national and international meetings and disseminated in a timely manner through peer-reviewed publications. All data produced through this program will be archived in the Biological and Chemical Oceanographic Data Management Office.

Anthropogenic climate change has emerged as a principle threat to coral reef survival in the 21st century. In addition to ocean warming and acidification, global climate models project enhanced stratification of the upper oceans through the 21st century and a consequent decline in productivity, by up to 50%, in the North Atlantic. This project employs controlled laboratory manipulation experiments to test the link between productivity and growth of the dominant reef-building corals across the Caribbean and Bermuda. Preliminary data generated by the investigators, including multi-decade long coral growth histories and nitrogen isotope ratios of coral tissue and skeleton, suggest that coral growth across the region has declined over the past 50 years in response to productivity changes already underway. If the link between ocean circulation, productivity decline, and coral growth is verified, the projected 21st century decline in productivity could rival and will certainly exacerbate the effects of warming and ocean acidification on North Atlantic coral reef ecosystems.