Coral community response to bleaching on a highly disturbed reef

Abstract

While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress.

Marked annual coral bleaching resilience of an inshore patch reef in the Florida Keys: A nugget of hope, aberrance, or last man standing?

“…Oliver and Palumbi (2011) showed that conspecifics that originate in environments with larger annual temperature fluctuations have greater heat tolerance than corals that originate from less fluctuating environments regardless of symbiont type. The higher turbidity may also be a key characteristic of Cheeca Rocks as a turbid reef site in Singapore was shown to be highly resilient to bleaching (Guest et al 2016). A similar pattern occurred in Palau, where coral bleaching and mortality were lower in sheltered bays that experience higher temperatures and lower irradiance due to high suspended particulate matter (van Woesik et al 2012).…”

“…Suboptimal environmental conditions appear to lend some degree of resistance and resilience to bleaching as has been shown in Singapore and Palau (van Woesik et al 2012;Guest et al 2016) and suggest that these reef sites likely deserve special attention. The next research step is to try and unravel the biological versus environmental factors that are leading to the resilience of the coral community at Cheeca Rocks and compare/contrast the key attributes with other sites around the globe.…”

Baseline reef health surveys at Bangka Island (North Sulawesi, Indonesia) reveal new threats

“…Observing high levels of bleaching at any given time is often a worrying trend. However, the lack of major diseases in this region is a promising sign, as studies have shown that bleaching events on their own do not necessarily change the coral taxonomic community structure despite often resulting in a reduced amount of total coral cover (Guest et al, 2016). …”

Large fluctuations but constant mean temperatures allow corals to persist in intertidal rock pools on the east coast of South Africa

“…Corals of these genera are widespread, hardy and abundant in most reef habitats [24], often being referred to as 'weedy' or 'tramp' species. However, they are not regarded as being particularly resilient to thermal stress [25,26]. Anomastrea irregualris, to our knowledge, has only been previously reported at a high latitude reef in the Arabian Gulf [23], but since its distribution is limited to the Western Indian Ocean region and the Gulf [24], there are limited possible locations for its occurrence.…”