Climate change blamed for Caribbean coral deaths

Chew Bakar SG

LONDON (Reuters) – Climate change has contributed to a flattening of the complex, multi-layered architecture of Caribbean coral reefs, compromising their role as a nursery for fish stocks and a buffer against tropical storms, a study shows.

The analysis of 500 surveys of 200 reefs, conducted between 1969 and 2008, showed the most complex types of reef had been virtually wiped out across the entire Caribbean.

Such reefs -- typified by Table Corals of over 1 meter across and huge antler-shaped Staghorn Corals -- act as a sanctuary for local fish stocks and a hunting ground for larger, commercially fished species.

Many have been replaced with the flattest types of rubble-strewn reef, which now cover about three quarters of the Caribbean's reef area, up from about a fifth in the 1970s, said the study, published in the Royal Society journal Biology Letters.

The biggest impact has occurred in the last decade, said the report by researchers from Britain's University of East Anglia and Canada's Simon Fraser University.

"Lack of ... refuges for species with commercial importance, such as lobsters and large fishes may compromise the long-term sustainability of fisheries and fishing communities," the report said.

Flatter reefs are also less effective in protecting coastal homes and villages from storm swells and tidal surges.

"The importance of this is going to increase," said Lorenzo Alvarez of the University of East Anglia, who led the study. "Many scientists think there will be more hurricanes in the future."

The degradation of Caribbean reefs is not entirely linked to climate change, with disease killing about 90 percent of Elkhorn and Staghorn Corals in the 1970s, but a second period of coral destruction is now under way.

New damage is typified by "coral bleaching," which occurs when the tiny organisms that build coral reefs become stressed and abandon their colonies.

"We suggest that the last period of decline is partly due to climate change, but also due to several other human impacts such as over-fishing and coastal development," Alvarez said. "In future, we'll need to change our behavior and reduce the stress on the reefs."

(Writing by Pete Harrison; Editing by Jon Hemming)

lianamaster SG

Didn't have the chance to see corals upclose in the sea other than looking at some random exhibits on land...

Chew Bakar SG

Didn't have the chance to see corals upclose in the sea other than looking at some random exhibits on land...

Didn't need to go far, just a mask and snorkel or wait for a good lowtide, you will see them.

lianamaster SG

Didn't need to go far, just a mask and snorkel or wait for a good lowtide, you will see them.

Where can see? Ubin?

Chew Bakar SG

Where can see? Ubin?

At the southern islands; you can see some around the Fort Siloso or Kusu or St John lsland. Ubin is sand flat or mangrove.

lianamaster SG

Oic...

MyNameisNas SG

Less polar cap>lesser solar ray reflector>oceans absorb solar ray> ocean temp increase>ocean absorb more C02>ocean acidification. tadaa!

Bangulzai SG

Wednesday, June 10, 2009

Coral reefs throughout the Caribbean have been comprehensively 'flattened' over the last 40 years, according to a disturbing new study by the University of East Anglia (UEA).

The collapse of reef structure has serious implications for biodiversity and coastal defences – a double whammy for fragile coastal communities in the region.

It was already known that coral cover in the Caribbean was in decline, but this is the first large scale study showing exactly what this means for the architecture of the region's reefs.

Published online on Wednesday June 10 by the peer-reviewed journal Proceedings of the Royal Society B, the researchers found that the vast majority of reefs have lost their complex structure and become significantly flatter and more uniform. The most complex reefs have been virtually wiped out.

The researchers, working with colleagues at Simon Fraser University in Canada, analysed changes in the structure of reefs using 500 surveys across 200 reefs conducted between 1969 and 2008. They found that 75 per cent of the reefs are now largely flat, compared with 20 per cent in the 1970s.

There have been two major periods of reef flattening. The first occurred when a widespread disease killed about 90 per cent of the Elkhorn and Staghorn corals in the late 1970s. The second period has been underway more recently and is thought to have been caused by an increase in the intensity and frequency of coral bleaching events, as a consequence of human-induced climate change increasing sea surface temperatures.

Lead researcher Lorenzo Alvarez-Filip, of UEA's School of Biological Sciences, said: "For many organisms, the complex structure of reefs provides refuge from predators. This drastic loss of architectural complexity is clearly driving substantial declines in biodiversity, which will in turn affect coastal fishing communities.

"The loss of structure also vastly reduces the Caribbean's natural coastal defences, significantly increasing the risk of coastal erosion and flooding."

Reversing declines in reef architecture now poses a major challenge for scientists and policy-makers concerned with maintaining reef ecosystems and the security and well-being of Caribbean coastal communities.

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University of East Anglia

Thanks to University of East Anglia for this article.