Project: Regional Variability in Future Temperature Stress to Coral Reefs in the Coral Triangle

The primary aim of this project is to test the oceanographic conditions that lead to regional differences in coral bleaching across the Coral Triangle, and to determine how changes in these conditions will influence coral bleaching patterns in the 21st Century. Degradation of coral reef ecosystems has accelerated over the past few decades due to increases in coral bleaching. Many uncertainties remain, however, regarding coral reef vulnerability to future bleaching conditions. This research will incorporate a high-resolution oceanographic model to simulate circulation and temperature patterns that promote coral bleaching, taking into account both the exposure of coral reefs to temperature stress as well as the sensitivity of those reefs to bleaching and their capacity to adapt to the temperature changes. The focus on the Coral Triangle is important because 1) it supports high marine biodiversity; 2) the complex bathymetry and oceanographic circulation are likely to provide significant insights into present and future conditions that affect coral reef vulnerability to increasing temperature; and 3) recent developments linking climate and regional circulation models can now resolve the complex oceanography in this area.

A Regional Ocean Modeling System developed for the Coral Triangle (CT-ROMS) will be used to examine climate change effects on temperature and circulation patterns in the Coral Triangle. The modeling will include several 21st Century runs forced by climate model projections using scenarios developed for the Intergovernmental Panel on Climate Change (IPCC) Assessment Report. Multiple bleaching algorithms that take into account different measures of heat stress and coral sensitivity to that stress will be evaluated for their ability to simulate observed bleaching patterns. The algorithms that best capture observed bleaching patterns will then be used to project bleaching in the 21st Century integrations. This will be the first project to undertake a comprehensive use of high resolution modeling to evaluate 1) the oceanographic conditions that determine regional variability in coral bleaching, and 2) how oceanographic changes will influence coral bleaching patterns in the future. We will be able to evaluate vulnerability to bleaching not only for reefs at the surface but also at depth, thus identifying whether deeper-water reefs should be considered sites for future conservation efforts.

This project will also provide a more complete picture of coral reef vulnerability in the Coral Triangle, and improve our ability to identify refugia for coral reefs, which is a cornerstone for Marine Protected Area (MPA) design and management. In collaboration with The Nature Conservancy, this work will contribute to efforts of the Coral Triangle Initiative Program Support Team to both maximize the application of the scientific results in MPA design, and improve the capacity of local fisheries and their communities to adapt to climate change impacts on their marine resources.

Data: See:

http://oceanus.esm.rutgers.edu:8080/thredds/ROMS/CORAL/catalog.html

Additional information, as well as results, can be found at: www.ctroms.ucar.edu.