Rapid onsets of warming events trigger mass mortality of coral reef fish

Amatzia Genin, Liraz Levy, Galit Sharon, Dionysios E. Raitsos, Arik Diamant

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Our study reveals a hitherto overlooked ecological threat of climate change. Studies of warming events in the ocean have typically focused on the events' maximum temperature and duration as the cause of devastating disturbances in coral reefs, kelp forests, and rocky shores. In this study, however, we found that the rate of onset (Ronset), rather than the peak, was the likely trigger of mass mortality of coral reef fishes in the Red Sea. Following a steep rise in water temperature (4.2 °C in 2.5 d), thermally stressed fish belonging to dozens of species became fatally infected by Streptococcus iniae. Piscivores and benthivores were disproportionately impacted whereas zooplanktivores were spared. Mortality rates peaked 2 wk later, coinciding with a second warming event with extreme Ronset. The epizootic lasted ~2 mo, extending beyond the warming events through the consumption of pathogen-laden carcasses by uninfected fish. The warming was widespread, with an evident decline in wind speed, barometric pressure, and latent heat flux. A reassessment of past reports suggests that steep Ronsetwas also the probable trigger of mass mortalities of wild fish elsewhere. If the ongoing increase in the frequency and intensity of marine heat waves is associated with a corresponding increase in the frequency of extreme Ronset, calamities inflicted on coral reefs by the warming oceans may extend far beyond coral bleaching.

    Original languageEnglish
    Pages (from-to)25378-25385
    Number of pages8
    JournalProceedings of the National Academy of Sciences of the United States of America
    Volume117
    Issue number41
    DOIs
    StatePublished - 13 Oct 2020

    Bibliographical note

    Funding Information:
    ACKNOWLEDGMENTS. We thank the Israel NMP in the Gulf of Eilat for providing the invaluable environmental data. We thank members of the NMP, IUI, and Nature and Park Authority in Eilat; and Orie Legum and the many divers, snorkelers, and residents of Eilat for their contribution to the campaign of recording and collecting carcasses. We thank local dive centers, editors of local and national newspapers, and social media administrators for their contribution to the call for this citizen-science campaign. We thank Roberto Ehrlich for his help with the necropsy and its analysis. We thank the Israel Meteorological Service for wind data from their station “Elat” and the GHRSST from the NASA EOSDIS PO.DAAC at the Jet Propulsion Laboratory (Pasadena, CA) for the satellite-derived SST products. Parts of the study were supported by grants from the Israel Science Foundation (1211/14) and Israel Ministry of Science and Technology (3-16729) (to A.G.). The NMP is funded by the Israel Ministry of Environmental Protection. We thank Sophie Dove, Ove Hoegh-Guldberg, Margarita Zarubin, and Daniela Genin for insightful discussions on the ecology of the warming event, and L. G. C. Genevier and G. Krokos for helping with the analysis of remote sensing and atmospheric circulation. We thank Prof. Steve Brenner (Bar Ilan University) for the calculations and interpretation of the heat flux dynamics. Comments and suggestions made by two anonymous reviewers greatly improved the manuscript.

    Funding Information:
    We thank the Israel NMP in the Gulf of Eilat for providing the invaluable environmental data. We thank members of the NMP, IUI, and Nature and Park Authority in Eilat; and Orie Legum and the many divers, snorkelers, and residents of Eilat for their contribution to the campaign of recording and collecting carcasses. We thank local dive centers, editors of local and national newspapers, and social media administrators for their contribution to the call for this citizen-science campaign. We thank Roberto Ehrlich for his help with the necropsy and its analysis. We thank the Israel Meteorological Service for wind data from their station "Elat" and the GHRSST from the NASA EOSDIS PO.DAAC at the Jet Propulsion Laboratory (Pasadena, CA) for the satellite-derived SST products. Parts of the study were supported by grants from the Israel Science Foundation (1211/14) and Israel Ministry of Science and Technology (3-16729) (to A.G.). The NMP is funded by the Israel Ministry of Environmental Protection. We thank Sophie Dove, Ove Hoegh-Guldberg, Margarita Zarubin, and Daniela Genin for insightful discussions on the ecology of the warming event, and L. G. C. Genevier and G. Krokos for helping with the analysis of remote sensing and atmospheric circulation. We thank Prof. Steve Brenner (Bar Ilan University) for the calculations and interpretation of the heat flux dynamics. Comments and suggestions made by two anonymous reviewers greatly improved the manuscript.

    Publisher Copyright:
    © 2020 National Academy of Sciences. All rights reserved.

    Keywords

    • Epizootic
    • Heat flux
    • Red Sea
    • Streptococcus
    • Warming rate

    ASJC Scopus subject areas

    • General

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