Nitrogen pollution interacts with heat stress to increase coral bleaching across the seascape.

Autor:	Donovan MK; Marine Science Institute, University of California, Santa Barbara, CA 93106; donovan.maryk@gmail.com dburkepile@ucsb.edu., Adam TC; Marine Science Institute, University of California, Santa Barbara, CA 93106., Shantz AA; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106.; Department of Biology, Pennsylvania State University, University Park, PA 16802., Speare KE; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106., Munsterman KS; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106., Rice MM; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106., Schmitt RJ; Marine Science Institute, University of California, Santa Barbara, CA 93106.; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106., Holbrook SJ; Marine Science Institute, University of California, Santa Barbara, CA 93106.; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106., Burkepile DE; Marine Science Institute, University of California, Santa Barbara, CA 93106; donovan.maryk@gmail.com dburkepile@ucsb.edu.; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2020 Mar 10; Vol. 117 (10), pp. 5351-5357. Date of Electronic Publication: 2020 Feb 24.
DOI:	10.1073/pnas.1915395117
Abstrakt:	Climate change is increasing the frequency and magnitude of temperature anomalies that cause coral bleaching, leading to widespread mortality of stony corals that can fundamentally alter reef structure and function. However, bleaching often is spatially variable for a given heat stress event, and drivers of this heterogeneity are not well resolved. While small-scale experiments have shown that excess nitrogen can increase the susceptibility of a coral colony to bleaching, we lack evidence that heterogeneity in nitrogen pollution can shape spatial patterns of coral bleaching across a seascape. Using island-wide surveys of coral bleaching and nitrogen availability within a Bayesian hierarchical modeling framework, we tested the hypothesis that excess nitrogen interacts with temperature anomalies to alter coral bleaching for the two dominant genera of branching corals in Moorea, French Polynesia. For both coral genera, Pocillopora and Acropora , heat stress primarily drove bleaching prevalence (i.e., the proportion of colonies on a reef that bleached). In contrast, the severity of bleaching (i.e., the proportion of an individual colony that bleached) was positively associated with both heat stress and nitrogen availability for both genera. Importantly, nitrogen interacted with heat stress to increase bleaching severity up to twofold when nitrogen was high and heat stress was relatively low. Our finding that excess nitrogen can trigger severe bleaching even under relatively low heat stress implies that mitigating nutrient pollution may enhance the resilience of coral communities in the face of mounting stresses from global climate change. Competing Interests: The authors declare no competing interest.
Databáze:	MEDLINE
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