New manuscript shows that warming has reversed long-standing environmental gradients on eastern Pacific coral reefs

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Reefs off the Pacific coast of Panama provide an ideal natural laboratory to study the influence of oceanographic and climatic variability on coral-reef ecosystems.

In the Gulf of Panama, reefs are exposed to strong seasonal upwelling, whereas upwelling is weak in the Gulf of Chiriqui. For millennia, conditions in the Gulf of Chiriqui have been warmer and more stable than in the Gulf of Panama, favoring more rapid coral growth and more extensive reef accretion. However, a recent study by Research Oceanographer Lauren Toth and academic colleagues published in the journal Ecology showed that in contrast to historical trends, the abundance of living coral, coral survival, and coral growth rates are all now significantly higher in the Gulf of Panama.

Over the last 150 years, temperatures have risen at a much faster rate in the Gulf of Chiriqui, and, during the 2015–2016 El Niño event, corals bleached extensively there, whereas upwelling in the Gulf of Panama moderated the high temperatures caused by El Niño, allowing the corals largely to escape thermal stress. The study suggests that as the climate continues to warm, upwelling zones may offer a temporary, localized refuge from the thermal impacts of climate change.

This research was conducted as part a NSF-funded project awarded to Toth and collaborators at Florida Institute of Technology, and Scripps Institution of Oceanography and the USGS Coral Reef Ecosystem Studies (CREST) project. It was conducted in collaboration with researchers at the Australian Institute of Marine Science Florida Institute of Technology, Scripps Institution of Oceanography, and the Smithsonian Tropical Research Institute.

The publication can be found at  https://doi.org/10.1002/ecy.2918.