AsianScientist (Nov. 14, 2016) – Although Singapore’s reefs have suffered extensive damage over the last 27 years, they have proven to be more resilient than expected, according to a study published in Scientific Reports.
In the past 200 years, Singapore has been transformed from a forest-covered island to a highly urbanized city-state of more than 5.4 million. Extensive coastal construction, dredge spillage and land reclamation have resulted in high sedimentation rates, turbidity and pollution, putting immense pressure on the surrounding coral reefs.
Analyzing surveys conducted between 1986 to 2012, researchers from the National University of Singapore, Nanyang Technological University, Singapore’s National Parks Board, the University of New South Wales and the Sydney Institute of Marine Science found that coral cover declined at all sites, particularly in the first decade.
In 1998, a major bleaching event occurred as the result of high water temperatures associated with an El Nino. However, corals at shallower reef sites were remarkably resilient to this event, showing signs of recovery within a decade. By 2008 coral cover had increased to about 1993 levels.
“It is remarkable that diverse shallow coral communities can persist in such adverse conditions,” says study first author Dr. James Guest, formerly of UNSW and now at the Hawai’i Institute of Marine Biology.
“Undoubtedly, Singapore’s reefs have suffered as a result of human activities, but the recovery of corals at shallow sites is really surprising given how impacted this environment is. It really shows how tough corals can be.”
However, the study also showed that corals at deeper sites were less resilient, with coral cover at these sites continuing to decline. The lack of recovery at deeper sites may be due to low light levels or a lack of unsuitable substratum for new corals to settle and survive.
Reefs in Singapore appear to have undergone substantial bleaching again this year, which is likely to test whether the resilience to bleaching observed in previous decades is still present on these reefs.
The article can be found at: Guest et al. (2016) 27 Years of Benthic and Coral Community Dynamics on Turbid, Highly Urbanized Reefs Off Singapore.
Source: University of New South Wales; Photo: Shutterstock.
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