Coral community bleaching response on a highly urbanised reef
- Published
- Accepted
- Subject Areas
- Ecology, Marine Biology
- Keywords
- Coral bleaching, thermal tolerance, Singapore, Bleaching susceptibility
- Copyright
- © 2014 Guest et al.
- Licence
- 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
- 2014. Coral community bleaching response on a highly urbanised reef. PeerJ PrePrints 2:e760v1 https://doi.org/10.7287/peerj.preprints.760v1
Abstract
Projected increases in the magnitude and frequency of sea surface temperature anomalies present a significant threat to the persistence of tropical coral reefs, however, detailed studies of community level responses to thermal stress are needed if its effect on reef resilience are to be understood. While many studies report on broad, regional scale responses to thermal stress (e.g., proportion of corals bleached), far fewer examine variation in susceptibility among taxa and change in coral community structure, before, during and after bleaching on individual reefs. Furthermore, relatively few studies of bleaching response come from highly urbanised reefs that experience chronic disturbances such as elevated sedimentation and turbidity. Here we report in detail on the bleaching response of corals at a highly urbanised reef site south of mainland Singapore during (June, July) and immediately after (October) a major thermal coral bleaching event in 2010. To estimate the capacity for resistance and resilience to thermal stress, we report on a) the overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event and c) the response of the reef in terms of taxonomic community structure before (2009) and after (2012) bleaching. Despite severe bleaching in 2010 (66% of colonies bleached), post-bleaching recovery appeared to be relatively rapid and coral taxa that are usually highly susceptible (e.g., Acropora and Pocillopora) were relatively unaffected, i.e., either they did not bleach or they bleached and recovered. Although there was no significant change in coral taxonomic community structure among years, taxa that bleached most severely tended to have the greatest reductions in relative cover. Several factors may have contributed to the overall high resistance of this site to bleaching including turbidity, symbiont affiliation and heterotrophy. A parsimonious explanation for the reversed pattern of bleaching susceptibility among taxa is that these coral populations have adapted and/or acclimatised to thermal stress. Despite ongoing chronic anthropogenic impacts, we suggest that this site has potential for rapid recovery of coral cover due to the dominant coral taxa and growth forms being capable of rapid regrowth from remnant colonies.
Author Comment
This study documents the response of an assemblage of corals to thermal stress during 2010 an a highly urbanised Indo-Pacific reef.
Supplemental Information
Proportion of colonies with different bleaching responses
Table S1. Proportion (%) of colonies not bleached, moderately bleached, severely bleached and bleaching indices for all genera that had at least 5 colonies surveyed on all three survey occasions.
Change in relative coral cover
Table S2. Change in relative cover (%) of coral genera at Pulau Satumu between 2009 (before bleaching), 2010 (during bleaching) and 2012 (after bleaching). Genera are in order from the greatest reduction in relative cover to the greatest increase in relative cover between 2009 and 2012.