Heating rate and symbiont productivity are key factors determining thermal stress in the reef-building coral Acropora formosa

Middlebrook, Rachael, Anthony, Kenneth R.N., Hoegh-Guldberg, Ove and Dove, Sophie (2010) Heating rate and symbiont productivity are key factors determining thermal stress in the reef-building coral Acropora formosa. Journal of Experimental Biology, 213 7: 1026-1034. doi:10.1242/jeb.031633

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Author Middlebrook, Rachael
Anthony, Kenneth R.N.
Hoegh-Guldberg, Ove
Dove, Sophie
Title Heating rate and symbiont productivity are key factors determining thermal stress in the reef-building coral Acropora formosa
Formatted title
Heating rate and symbiont productivity are key factors determining thermal stress in the reef-building coral Acropora formosa
Journal name Journal of Experimental Biology   Check publisher's open access policy
ISSN 0022-0949
1477-9145
Publication date 2010-04-01
Sub-type Article (original research)
DOI 10.1242/jeb.031633
Open Access Status File (Publisher version)
Volume 213
Issue 7
Start page 1026
End page 1034
Total pages 9
Place of publication Cambridge, United Kingdom
Publisher The Company of Biologists
Collection year 2011
Language eng
Subject C1
Formatted abstract
The onset of large-scale coral bleaching events is routinely estimated on the basis of the duration and intensity of thermal
anomalies determined as degree heating weeks. Degree heating weeks, however, do not account for differential rates of heating.
This study aimed to explore the relationship between different rates of heating above the documented regional winter threshold,
and resultant bleaching of the reef-building coral Acropora formosa. Under a relatively low light field, rapid heating of 1°C day–1
from 29°C to 32°C lead to a 17.6% decline in Fv/Fm, concurrent with a rapid increase in xanthophyll de-epoxidation sustained into
the dark, whereas slower heating rates of 0.5°C day–1 lead to no decline in Fv/Fm and no change in dark-adapted xanthophyll
cycling. At the winter bleaching threshold of 30°C, areal net O2 evolution exceeded the control values for rapidly heated corals,
but was lower than the controls for slowly heated corals. At the maximum temperature of 33°C, however, both treatments had net
O2 fluxes that were 50% of control values. At 30°C, only symbiont densities in the slowly heated controls were reduced relative to
controls values. By 33°C, however, symbiont densities were 55% less than the controls in both treatments. The rate of heat
accumulation was found to be an important variable, with rapidly heated corals attaining the same bleaching status and loss of
areal O2 production for half the degree heating week exposure as slowly heated corals. The study revealed that it is incorrect to
assume that significant dark acclimation disables non-photochemical quenching, because 75% of an increased xanthophyll pool
was found to be in the de-epoxidated state following rapid heat accumulation. This has important ramifications for the
interpretation of chlorophyll fluorescence data such as dark adapted Fv/Fm.
Keyword Acclimation
Coral bleaching
Heating rate
Photosynthetic productivity
Symbiodinium sp.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Global Change Institute Publications
Official 2011 Collection
Centre for Marine Studies Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 24 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 26 times in Scopus Article | Citations
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Created: Sun, 04 Apr 2010, 10:03:40 EST