Abstract: The 21st century warming and acidification of tropical oceans will impact the structure and function of coral reef ecosystems. Consequently, coral reef conservation efforts are increasingly focused on identifying and protecting reef communities that demonstrate resilience to these environmental changes. I am developing a scientific framework for identifying climate change resilience in coral communities. Using the coral reefs of the Palau archipelago as a case study, I demonstrate an initial application of this approach. First, I use coral skeletal records to evaluate the sensitivity of coral communities to multiple episodes of severe thermal stress. Skeletal records collected from massive corals document coral reef communities that consistently exhibit weak responses to multiple high temperature events. Second, I evaluate coral reef community structure across a strong, natural pH gradient using metrics informed by laboratory ocean acidification studies. I find that the coral communities of Palau’s Rock Island reefs show a level of pH tolerance that is unique amongst reefs studied to date. Third, I conduct laboratory and field experiments to constrain the pH thresholds of these corals and investigate potential mechanisms for pH tolerance. Finally, I combine archipelago-wide coral temperature and pH sensitivity data to construct climate change resilience indices.  My framework succeeds in identifying a small number of coral communities in Palau that have the potential to withstand 21st century climate change and highlights the spatial variability present in community responses to ocean warming and acidification. Critically, I present a set of scientific tools and approaches for identifying resilient coral reef communities that has applicability to coral reefs worldwide.

Biography: Hannah Barkley is a postdoctoral investigator at Woods Hole Oceanographic Institution in Massachusetts, USA. She holds a Ph.D. from the Massachusetts Institute of Technology-Woods Hole Oceanographic Institution Joint Program in Oceanography and an A.B. in Ecology and Evolutionary Biology from Princeton University. Her research focuses on evaluating coral reef responses and resilience to climate change. She applies a range of interdisciplinary scientific techniques to identify and understand coral reef communities that may be particularly resilient to ocean warming and ocean acidification over the next several decades. In addition, she is currently working with conservation organizations and local governments in Pacific Island nations to incorporate science-based climate change criteria into coral reef conservation planning and management.