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IMPACT OF NUTRIENT ENRICHMENT ON CORAL BLEACHING, MORTALITY, AND RECOVERY DURING THE 2015-16 EL NINO

The worldwide coral bleaching event during the 2015-16 El Nino provided an unparalleled opportunity to test the influence of human- versus fish-derived nutrients in altering the susceptibility of corals to bleaching and subsequent mortality. Based on differences in how nitrate versus urea enrichment affects the physiology of corals, it has been hypothesized that under stress, nutrient enrichment from anthropogenic sources (nitrate) could weaken the coral-dinoflagellate symbiosis, whereas recycled nitrogen excreted by reef fishes (urea/ammonium) may not be harmful. In a year-long in situ nutrient enrichment experiment on the fore reef of Moorea, French Polynesia done during the peak warm water period of the 2015-16 El Nino, we tested the impact of nitrate vs. urea on bleaching prevalence and severity for corals in the genera Pocillopora, Acropora, and Porites. Both Acropora and Pocillopora corals were more likely to bleach when they were enriched with nitrate or urea as compared to controls. Importantly, nitrate-enriched Pocillopora remained bleached whereas urea-enriched and control corals recovered. This difference in duration of bleaching resulted in far greater Pocillopora mortality under nitrate enrichment than under urea enrichment or control conditions. Our findings suggest that more human-derived forms of nitrogen can interact with El Nino-associated warm water events to exacerbate both bleaching and mortality of a prominent group of branching corals.

Authors

Holbrook, S. J., Univ. California Santa Barbara, USA, holbrook@lifesci.ucsb.edu

Burkepile, D. E., Univ. California Santa Barbara, USA, deron.burkepile@lifesci.ucsb.edu

Adam, T. C., Univ. California Santa Barbara, USA, thomas.adam@lifesci.ucsb.edu

Brooks, A. J., Univ. California Santa Barbara, USA, ajbrooks@ucsb.edu

Schmitt, R. J., Univ. California Santa Barbara, USA, schmitt@lifesci.ucsb.edu

Shantz, A. A., Univ. California Santa Barbara, USA, shantz@gmail.com

Details

Poster presentation

Session #:059
Date: 03/03/2017
Time: 15:30 - 16:30
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: 490