This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Putchim L, Phongsuwan N, Yaemarunpattana C, Thongtham N, Richter C.2017. Long-term changes in the susceptibility of corals to thermal stress around Phuket, Thailand. PeerJ Preprints5:e2979v1https://doi.org/10.7287/peerj.preprints.2979v1
The bleaching susceptibility of 28 coral taxa around southern Phuket was examined in four natural major bleaching events, in 1991, 1995, 2010, and 2016. Surveys were conducted by line intercept and belt transect methods. All coral colonies were identified to genus or species-level and their pigmentation status was assessed as: (1) fully pigmented (i.e. no bleaching), (2) pale (loss of colour), (3) fully bleached, and (4) recently dead as a result of bleaching-induced mortality. Bleaching and mortality indices were calculated to compare bleaching susceptibility among coral taxa. In 2016 some of the formerly bleaching susceptible coral taxa (e.g. Acropora, Montipora,Echinopora, and Pocillopora damicornis) showed far greater tolerance to elevated sea water temperature than in previous years. In P. damicornis the higher bleaching resistance encompassed all sizes from juveniles (<5cm) to adults (>30cm). In contrast, some of the formerly bleaching-resistant corals (e.g. the massive Porites, Goniastrea, Dipsastraea, and Favites) became more susceptible to bleaching over repeated thermal stressevents. Our results support the hypothesis that some of the fast-growing branching corals (Acropora, Montipora, and Pocillopora) may have life-history traits that lead to more rapid adaptation to a changed environment than certain growing massive species.
This is a submission to PeerJ for review.
Coral composition (by genus) at sites around the southern Phuket sea region regardless of bleaching status in the bleaching years 1991, 1995, 2010, and 2016
Differential mortality led to the near disappearance of branching species (e.g. Acropora), and increased dominance of massive Porites over this 25y period.