Publisher :
Place of publication :
Publication year : 2009
Thematic : Coral Reef
Language : English
Note
This study tested the effects of acclimatization
on the response of corals to elevated temperature, using
juvenile massive Porites spp. and branching P. irregularis
from Moorea (W149500, S17300). During April and
May 2006, corals were acclimatized for 15 days to cool
(25.7C) or ambient (27.7C) temperature, under shaded
(352 lmol photons m-2 s-1) or ambient (554 lmol photons
m-2 s-1) natural light, and then incubated for 7 days
at ambient or high temperature (31.1C), under ambient
light (659 lmol photons m-2 s-1). The response to
acclimatization was assessed as biomass, maximum darkadapted
quantum yield of PSII (Fv/Fm), and growth, and
the effect of the subsequent treatment was assessed as
Fv/Fm and growth. Relative to the controls (i.e., ambient
temperature/ambient light), massive Porites spp. responded
to acclimatization through increases in biomass
under ambient temperature/shade, and low temperature/
ambient light, whereas P. irregularis responded through
reduced growth under ambient temperature/shade, and
low temperature/ambient light. Acclimatization affected
the response to thermal stress for massive Porites spp.
(but not P. irregularis), with an interaction between the
acclimatization and subsequent treatments for growth.
This interaction resulted from a lessening of the negative
effects of high temperature after acclimatizing to ambient
temperature/shade, but an accentuation of the effect after
acclimatizing to low temperature/shade. It is possible that
changes in biomass for massive Porites spp. are important
in modulating the response to high temperature, with the
taxonomic variation in this effect potentially resulting
from differences in morphology. These results demonstrate
that corals can acclimatize during short exposures
to downward excursions in temperature and light, which
subsequently affects their response to thermal stress.
Moreover, even con-generic taxa differ in this capacity,
which could affect coral community structure.
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Keywords : Luperosaurus joloensis
Encoded by : Pauline Carmel Joy Eje