Food availability promotes rapid recovery from thermal stress in a scleractinian coral

Connolly, S.R., Lopez-Yglesias, M.A., and Anthony, K.R.N. (2012) Food availability promotes rapid recovery from thermal stress in a scleractinian coral. Coral Reefs, 31 (4). pp. 951-960.

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Abstract

Bleaching in corals due to environmental stress represents a loss of energy intake often leading to an increase in mortality risk. Successful coral recovery from severe bleaching events may depend on the rate of replenishment of algal symbiont populations following the period of thermal stress, the supply of an alternative food source, or both. Here, we explore the role of food availability in promoting the survival and recovery of a common coral (Acropora intermedia) following acute experimentally induced thermal stress. Fed corals were provided with live rotifers daily, to maintain densities of zooplankton in tanks that are typical of coral reefs. After a 6-week acclimation phase, heated corals were subjected to a +4 °C thermal anomaly for a 7-day period (bleaching phase) then temperatures were returned to normal for a further 2 weeks (recovery phase). Results demonstrated that heated corals had higher survival when they were provided with heterotrophic food. Fed corals experienced reduced loss of chlorophyll a, relative to unfed corals. During the recovery phase, both fed and unfed corals recovered within a few days; however, fed corals recovered to pre-bleaching phase levels of chlorophyll a, whereas unfed corals stabilized approximately one-third below this level. Protein levels of fed corals declined markedly during the bleaching phase, but recovered all of their losses by the end of the recovery phase. In contrast, unfed corals had low protein levels that were maintained throughout the experiment. To the extent that these results are representative of corals' responses to thermal anomalies in nature, the findings imply that availability of particulate food matter has the potential to increase corals' capacity to survive thermally induced bleaching and to ameliorate its sub-lethal effects. They also support the hypothesis that different rates of heterotrophy are an important determinant of variation in resilience to thermal stress among reef environments.

Item ID: 24405
Item Type: Article (Refereed Research - C1)
Keywords: coral bleaching, recovery, heterotrophy, phototrophy, nutrients
ISSN: 1432-0975
Date Deposited: 07 Jan 2013 04:46
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 50%
06 BIOLOGICAL SCIENCES > 0699 Other Biological Sciences > 069902 Global Change Biology @ 50%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960808 Marine Flora, Fauna and Biodiversity @ 50%
96 ENVIRONMENT > 9603 Climate and Climate Change > 960307 Effects of Climate Change and Variability on Australia (excl. Social Impacts) @ 50%
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