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Coral Immune Response to Physical Damage in Warmed Seawater

Paper Reviewed
van de Water, J.A.J.M., Leggat, W., Bourne, D.G., van Oppen, M.J.H., Willis, B.L. and Ainsworth, T.D. 2015. Elevated seawater temperatures have a limited impact on the coral immune response following physical damage. Hydrobiologia 759: 201-214.

Writing as introduction to their work, van de Water et al. (2015) state that -- in order to evaluate how elevated seawater temperatures affect coral immune responses following injuries caused by such things as predation and storm damage -- they collected fragments of Acropora aspera from the reef flat of Heron Island on Australia's Great Barrier Reef, which they brought to a nearby laboratory and maintained in seawater of either ambient (27-29°C) or elevated (32-33.5°C) for eight days, after which they experimentally injured the coral fragments and assessed what subsequently happened in terms of their immune responses. And what did they thereby learn?

The six scientists report that (1) "the immune response of A. aspera exhibited 24 hours post-injury was not significantly affected by mild temperature stress," that (2) "responses to injury under heat stress were as strong as those of non-heat-stressed corals," that (3) "gene expression levels of both the toll-like receptor pathway components and other immune effectors were largely unaffected at 24 hours post-injury," that (4) "genes potentially involved in wound repair and tissue regeneration were upregulated," that (5) "upregulation of components of the lectin-complement system, which is involved in the coral-Symbiodinium symbiosis, under heat stress suggests that corals were attempting to maintain the endosymbiosis," and that (6) "normal expression levels of immune genes in the initial response following injury may be sufficient to ward off invading microbes, enabling the coral to invest more heavily in tissue repair."

Consequently, and in light of these several observations, van de Water et al. conclude that (7) "this study provides evidence that some corals are capable of withstanding the adverse effects of physical damage under elevated temperatures."

Posted 24 December 2015