New USGS study suggests that high-latitude environments are unlikely to support coral reef growth as the climate warms

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The complex, three-dimensional structures built by coral reefs over thousands of years provide the foundation that supports critical “ecosystem services” for people living on reef-lined coasts including shoreline protection and habitat for fisheries species. Reef development has historically been limited in subtropical, high-latitude coral-reef habitats like those in South Florida because minimum temperatures hover just above the lower threshold for coral growth. However, recent range expansions of thermally sensitive, reef-building corals into these marginal environments as the climate has warmed have led to the hypothesis that subtropical habitats may serve as a refuge for coral reefs from high-temperature extremes in the future. Toth, along with SPCMSC Physical Scientist Anastasios Stathakopoulos and academic collaborators, tested this hypothesis by analyzing an extensive dataset of Holocene-age corals collected in coastal habitats from Miami to Palm Beach, FL (referred to as South Florida here). They showed that the relatively warm, stable climate ~10,000 to 8,000 years ago allowed reefs to expand their ranges poleward. Subsequent cooling drove the progressive contraction of the reefs to the south, and by 3,000 years ago reef-building had ceased throughout South Florida. The study suggests that modern climate change will not simply reverse this trend. Instead, by increasing the frequency of extreme weather events, including both intense warm and cold fronts, climate change will exaggerate the already-hostile environmental conditions in thermally marginal environments like South Florida, preventing reef-building from resuming in the future. 

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