Modeling photoinhibition-driven bleaching in Scleractinian coral as a function of light, temperature, and heterotrophy

Gustafsson, MSM; Baird, ME; Ralph, PJ

Modeling photoinhibition-driven bleaching in Scleractinian coral as a function of light, temperature, and heterotrophy

Gustafsson, MSM Baird, ME

Ralph, PJ

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Publication Type:: Journal Article
Citation:: Limnology and Oceanography, 2014, 59 (2), pp. 603 - 622
Issue Date:: 2014-01-01

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Field	Value	Language
dc.contributor.author	Gustafsson, MSM	en_US
dc.contributor.author	Baird, ME https://orcid.org/0000-0003-4955-2298	en_US
dc.contributor.author	Ralph, PJ https://orcid.org/0000-0002-3103-7346	en_US
dc.date.issued	2014-01-01	en_US
dc.identifier.citation	Limnology and Oceanography, 2014, 59 (2), pp. 603 - 622	en_US
dc.identifier.issn	0024-3590	en_US
dc.identifier.uri	http://hdl.handle.net/10453/34498
dc.description.abstract	It has been proposed that corals with symbiotic algae (Symbiodinium) bleach under thermal stress due to temperature-dependent inactivation of the Rubisco protein that impairs CO2 uptake, causing a backlog of electrons that result in the formation of damaging Reactive Oxygen Species. We present a numerical model of this mechanism of photoinhibition for symbiotic algae residing within coral tissue. The resulting rate of bleaching depended on temperature, light intensity, and the rate of heterotrophic feeding. The model was validated using three independently published experimental data sets. The model was capable of capturing both the diurnal change in the state of the photosystem, as well as changes in the symbiont population and the coral host caused by different temperature, light, and feeding treatments. Elevated temperatures and light led to a degradation of the photosystem and the expulsion of symbiont cells. If the coral fed heterotrophically, this degradation of the photosynthetic apparatus was reduced, but still a clear decrease in maximum quantum yield (Fv: Fm) and cell numbers was observed when the coral was exposed to elevated temperature. The reduction in chlorophyll content of cells at elevated temperatures and light was compared with the observational bleaching index Degree Heating Days (DHD). As quantified by DHD, the model was found to bleach under similar thermal stress regimes as field studies, except under elevated heterotrophic feeding conditions, which resulted in reduced severity of bleaching over a 90 d period. © 2014, by the Association for the Sciences of Limnology and Oceanography, Inc.	en_US
dc.relation.ispartof	Limnology and Oceanography	en_US
dc.relation.isbasedon	10.4319/lo.2014.59.2.0603	en_US
dc.subject.classification	Marine Biology & Hydrobiology	en_US
dc.title	Modeling photoinhibition-driven bleaching in Scleractinian coral as a function of light, temperature, and heterotrophy	en_US
dc.type	Journal Article
utslib.citation.volume	2	en_US
utslib.citation.volume	59	en_US
utslib.for	0607 Plant Biology	en_US
utslib.for	04 Earth Sciences	en_US
utslib.for	05 Environmental Sciences	en_US
utslib.for	06 Biological Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - C3 - Climate Change Cluster
utslib.copyright.status	open_access
pubs.issue	2	en_US
pubs.publication-status	Published	en_US
pubs.volume	59	en_US

Abstract:

It has been proposed that corals with symbiotic algae (Symbiodinium) bleach under thermal stress due to temperature-dependent inactivation of the Rubisco protein that impairs CO2 uptake, causing a backlog of electrons that result in the formation of damaging Reactive Oxygen Species. We present a numerical model of this mechanism of photoinhibition for symbiotic algae residing within coral tissue. The resulting rate of bleaching depended on temperature, light intensity, and the rate of heterotrophic feeding. The model was validated using three independently published experimental data sets. The model was capable of capturing both the diurnal change in the state of the photosystem, as well as changes in the symbiont population and the coral host caused by different temperature, light, and feeding treatments. Elevated temperatures and light led to a degradation of the photosystem and the expulsion of symbiont cells. If the coral fed heterotrophically, this degradation of the photosynthetic apparatus was reduced, but still a clear decrease in maximum quantum yield (Fv: Fm) and cell numbers was observed when the coral was exposed to elevated temperature. The reduction in chlorophyll content of cells at elevated temperatures and light was compared with the observational bleaching index Degree Heating Days (DHD). As quantified by DHD, the model was found to bleach under similar thermal stress regimes as field studies, except under elevated heterotrophic feeding conditions, which resulted in reduced severity of bleaching over a 90 d period. © 2014, by the Association for the Sciences of Limnology and Oceanography, Inc.

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http://hdl.handle.net/10453/34498