A new study concludes that the rate at which coral reefs die is two times faster than that at which rain forests are lost, urging scientists and state authorities to take action before it’s too late.
Scientists have noticed in recent years a sharp decline in the coral population, suspecting not one, but several factors for this unfortunate situation. Pollution, overfishing, auto-immune diseases and even natural events like earthquakes- all pose a threat to the rich ecosystem that forms near the reefs.
But the most enigmatic factor is the so-called white syndrome, a term coined by the Australian Institute of Marine Science in recognition of the difficulty in diagnosing a disease(s) of unknown pathology based simply on visual field characters or signs. Typically WS is expressed on a coral as a white band sharply cutting across live coral tissue with a clear area of necrosis where the dead white coral skeleton and the living coral colony meet.
A study published in May by the Public Archive of Science had found a significant link between oceans’ rising temperatures (caused by the global warming) and the incidence of the white syndrome among corals from Australia’s Great Barrier Reef.
A newer study on a similar subject warns the scientific community and the state authorities about the accelerated death rate registered for coral populations worldwide, a rate previously thought to be slower.
John Bruno and Elizabeth Selig of the University of North Carolina at Chapel Hill in the US analyzed data from 6000 studies that between them tracked the fate of 2600 reefs in the Indo-Pacific between 1968 and 2004.
Technically, a coral reef’s state of health is indicated by the presence of what is called the coral cover, which should be around 50% from the entire coral mass.
"The corals themselves build their limestone foundation, so if the surface of the reef is not covered with live tissue that is continually secreting it, the reef can erode fairly quickly," explains Selig.
"Twenty or 30 years ago reefs with a high cover of coral were fairly common," said study co-author Elizabeth Selig added.
"Today there are comparatively few reefs in the Indo-Pacific that we would traditionally think of as being pristine."
The research also revealed that the corals’ sharp decline began in the late 1960s- much earlier than had been assumed- and that in our days (year 2003 to be exact) only 20% of the coral reefs have a healthy coral cover.
Today only 2% of Indo-Pacific reefs have the same amount of live coral as they did in the 1980s.
It appears that protected coral areas and unprotected areas have small differences concerning overall health, both fairing bad."Well-managed reefs are definitely doing better in terms of fish population but not in terms of coral cover," Selig said.
"There certainly are local problems that [reef] managers can and are addressing," says Bruno. "But there are problems that are happening at regional and global scales that no single manager, or even federal authority can cope with. Managers can't manage ocean temperatures."
"The actions of people in Iowa, for example, have a big effect on people in small islands and throughout this whole Indo-Pacific region. It affects their livelihoods dramatically," Dr Bruno told the BBC.
"When corals died, there were some studies which showed how quickly the dive shops and the hotels closed down."
