Heat budget and thermal microenvironment of shallow-water corals: Do massive corals get warmer than branching corals?

Jimenez, IM; Kühl, M; Larkum, AWD; Ralph, PJ

Heat budget and thermal microenvironment of shallow-water corals: Do massive corals get warmer than branching corals?

Jimenez, IM Kühl, M

Larkum, AWD

Ralph, PJ

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Publication Type:: Journal Article
Citation:: Limnology and Oceanography, 2008, 53 (4), pp. 1548 - 1561
Issue Date:: 2008-01-01

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Field	Value	Language
dc.contributor.author	Jimenez, IM	en_US
dc.contributor.author	Kühl, M https://orcid.org/0000-0002-1792-4790	en_US
dc.contributor.author	Larkum, AWD https://orcid.org/0000-0002-0420-134X	en_US
dc.contributor.author	Ralph, PJ https://orcid.org/0000-0002-3103-7346	en_US
dc.date.issued	2008-01-01	en_US
dc.identifier.citation	Limnology and Oceanography, 2008, 53 (4), pp. 1548 - 1561	en_US
dc.identifier.issn	0024-3590	en_US
dc.identifier.uri	http://hdl.handle.net/10453/12778
dc.description.abstract	Coral surface temperature was investigated with multiple temperature sensors mounted on hemispherical and branching corals under (a) artificial lighting and controlled flow; (b) natural sunlight and controlled flow; and (c) in situ conditions in a shallow lagoon, under naturally fluctuating irradiance, water flow, and temperature. Under high irradiance and low flow conditions, hemispherical corals were 0.6°C warmer than the surrounding water. Hemispherical corals reached higher temperatures than branching corals, by a measure of 0.2°C to 0.4°C. Microsensor temperature measurements showed the presence of a thermal boundary layer (TBL). The TBL thickness was flow dependent, and under low flow conditions, a TBL up to 3 mm thick limited heat transfer to the ambient water. Combined microsensor measurements of temperature and oxygen showed that the TBL was approximately four times thicker than the diffusive boundary layer, as predicted from heat and mass transfer theory. A simple conceptual model describes coral surface temperature as a function of heat fluxes between coral tissue, skeleton, and surroundings. The slope of the predicted linear relationship between coral temperature and solar irradiance is fixed by the efficiencies of light absorption and the heat losses to the skeleton and the water. Although spectral absorptivity may play a significant role in coral warming, shape-related differences in thermal properties can cause hemispherical corals to reach higher temperatures than branching corals. Shape-related differences in thermal histories may thus help explain differences in susceptibility to coral bleaching between branching and hemispherical coral species. © 2008, by the American Society of Limnology and Oceanography, Inc.	en_US
dc.relation.ispartof	Limnology and Oceanography	en_US
dc.relation.isbasedon	10.4319/lo.2008.53.4.1548	en_US
dc.subject.classification	Marine Biology & Hydrobiology	en_US
dc.title	Heat budget and thermal microenvironment of shallow-water corals: Do massive corals get warmer than branching corals?	en_US
dc.type	Journal Article
utslib.citation.volume	4	en_US
utslib.citation.volume	53	en_US
utslib.for	0602 Ecology	en_US
utslib.for	04 Earth Sciences	en_US
utslib.for	05 Environmental Sciences	en_US
utslib.for	06 Biological Sciences	en_US
dc.location.activity	ISI:000257773700032	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	4	en_US
pubs.publication-status	Published	en_US
pubs.volume	53	en_US

Abstract:

Coral surface temperature was investigated with multiple temperature sensors mounted on hemispherical and branching corals under (a) artificial lighting and controlled flow; (b) natural sunlight and controlled flow; and (c) in situ conditions in a shallow lagoon, under naturally fluctuating irradiance, water flow, and temperature. Under high irradiance and low flow conditions, hemispherical corals were 0.6°C warmer than the surrounding water. Hemispherical corals reached higher temperatures than branching corals, by a measure of 0.2°C to 0.4°C. Microsensor temperature measurements showed the presence of a thermal boundary layer (TBL). The TBL thickness was flow dependent, and under low flow conditions, a TBL up to 3 mm thick limited heat transfer to the ambient water. Combined microsensor measurements of temperature and oxygen showed that the TBL was approximately four times thicker than the diffusive boundary layer, as predicted from heat and mass transfer theory. A simple conceptual model describes coral surface temperature as a function of heat fluxes between coral tissue, skeleton, and surroundings. The slope of the predicted linear relationship between coral temperature and solar irradiance is fixed by the efficiencies of light absorption and the heat losses to the skeleton and the water. Although spectral absorptivity may play a significant role in coral warming, shape-related differences in thermal properties can cause hemispherical corals to reach higher temperatures than branching corals. Shape-related differences in thermal histories may thus help explain differences in susceptibility to coral bleaching between branching and hemispherical coral species. © 2008, by the American Society of Limnology and Oceanography, Inc.

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http://hdl.handle.net/10453/12778