Increased dominance of heat-tolerant symbionts creates resilient coral reefs in near-term ocean warming.
Ana M Palacio-Castro, Tyler B Smith, Viktor Brandtneris, Grace A Snyder, Ruben van Hooidonk, Juan L Maté, Derek Manzello, Peter W Glynn, Peggy Fong, Andrew C Baker
Author Information
Ana M Palacio-Castro: Department of Marine Biology and Ecology, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL 33149. ORCID
Tyler B Smith: Coral Reefs Research, Reefs Unknown, Saint Thomas, US Virgin Islands 00802. ORCID
Viktor Brandtneris: Coral Reefs Research, Reefs Unknown, Saint Thomas, US Virgin Islands 00802.
Grace A Snyder: Department of Marine Biology and Ecology, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL 33149. ORCID
Ruben van Hooidonk: Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149. ORCID
Juan L Maté: Smithsonian Tropical Research Institute, Balboa, Ancon 0843-03092, Panama. ORCID
Derek Manzello: Coral Reef Watch, Center for Satellite Applications and Research, Satellite Oceanography & Climatology Division, U.S. National Oceanic and Atmospheric Administration, MD 20740.
Peter W Glynn: Department of Marine Biology and Ecology, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL 33149.
Peggy Fong: Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095.
Andrew C Baker: Department of Marine Biology and Ecology, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL 33149. ORCID
Climate change is radically altering coral reef ecosystems, mainly through increasingly frequent and severe bleaching events. Yet, some reefs have exhibited higher thermal tolerance after bleaching severely the first time. To understand changes in thermal tolerance in the eastern tropical Pacific (ETP), we compiled four decades of temperature, coral cover, coral bleaching, and mortality data, including three mass bleaching events during the 1982 to 1983, 1997 to 1998 and 2015 to 2016 El Niño heatwaves. Higher heat resistance in later bleaching events was detected in the dominant framework-building genus, while other coral taxa exhibited similar susceptibility across events. Genetic analyses of spp colonies and their algal symbionts (2014 to 2016) revealed that one of two lineages present in the region (type 1") increased its association with thermotolerant algal symbionts () during the 2015 to 2016 heat stress event. This lineage experienced lower bleaching and mortality compared with "type 3", which did not acquire . Under projected thermal stress, ETP reefs may be able to preserve high coral cover through the 2060s or later, mainly composed of colonies that associate with . However, although the low-diversity, high-cover reefs of the ETP could illustrate a potential functional state for some future reefs, this state may only be temporary unless global greenhouse gas emissions and resultant global warming are curtailed.
