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Coral Reefs in the Anthropocene Ocean: Novel Insights from Skeletal Proxies of Climate Change, Impacts, and Resilience

Nathaniel Mollica, Ph.D., 2021
Anne Cohen, Co-Advisor
Weifu Guo, Co-Advisor

and rapid ocean acidification (OA). Ensuring survival of coral reefs will require a new management approach that incorporates robust understanding of reef-scale climate change its impact on corals, and their potential for adaptation. In this thesis, I extract information from within coral skeletons to 1) Quantify the changes occurring on coral reefs and the effects on coral growth, 2) Identify differences in the sensitivity of coral reefs, and 3) Evaluate their adaptation potential. First, I develop a model to show coral that skeletal density is vulnerable to OA and that, 21st century OA projections will reduce coral skeletal density globally. Second, I use a skeletal bleaching proxy to quantify coral responses to heatwaves in the central equatorial Pacific (CEP) revealing a long history of bleaching in the region and reef-specific differences in thermal tolerance. Third, I improve the Sr-U paleo-thermometer to generate monthly-resolved sea surface temperatures (SST) using laser ablation ICPMS. Finally, I reconstruct the past 100 years of SST at Jarvis Island in the CEP, and show that a coral population on Jarvis Island has not yet adapted to the pace of anthropogenic climate change.