Award: OCE-1234674

In this project we aimed to examine how spatial and temporal patterns of coral bleaching within the Coral Triangle may change over the 21st Century, with a better understanding of the physical and biological mechanisms driving those changes. The work aimed to address two aspects of coral bleaching and its projections: (1) what is the regional variability in temperature patterns in the Coral Triangle, over past, present and future time-scales and what are the mechanisms for those variations; and (2) how well does the present suite of algorithms for calculating temperature stress predict coral bleaching in the Coral Triangle. We have developed a high-resolution (~5 km) Regional Ocean Modeling System for the Coral Triangle (CT-ROMS) to (1) analyze the oceanographic forcing that affects the temporal and spatial variability of temperature in the Coral Triangle, as well as other variables such as current velocities and mixed layer depth; (2) determine how climate change will alter those patterns in the 21st Century; and (3) determine the relative impacts of different assumptions regarding calculation of coral thermal stress and adaptation to that stress. This project has provided the first in-depth analysis of the patterns of ocean temperature in the Coral Triangle over century-long time scales, and how those patterns determine heat stress that leads to coral bleaching. We determined that even though most heat stress in the Coral Triangle is associated with ENSO events, that heat stress is largely driven by the background warming associated with longer term oscillations and climate change. We have identified several regions that have consistently experienced the lowest heat stress over the past 50 years, a few of which persist as regions of lower heat stress into the future. Reefs that occur at depths betwen 20 and 50 m also experience low heat stress, and may constitute thermal refugia into the future. These findings are being used extensively in both field exercises and in planning for Marine Protected Areas for the Coral Triangle Initiative. We have published two journal articles and have at least two more in preparation. The work has sparked interest in applying CT-ROMS for many other research objectives, particularly for students and post-doctoral researchers working with Joanie Kleypas and Enrique Curchitser. Last Modified: 01/05/2015 Submitted by: Enrique N Curchitser