Wildlife Conservation Society and partners document large-scale coral bleaching and death in wake of sea surface temperature rise
The Wildlife Conservation Society today released initial field observations that indicate that a dramatic rise in the surface temperature in Indonesian waters has resulted in a large-scale bleaching event that has devastated coral populations.
WCS's Indonesia Program "Rapid Response Unit" of marine biologists was dispatched to investigate coral bleaching reported in May in Aceh – a province of Indonesia – located on the northern tip of the island of Sumatra. The initial survey carried out by the team revealed that over 60 percent of corals were bleached."Bleaching"– a whitening of corals that occurs when algae living within coral tissues are expelled – is an indication of stress caused by environmental triggers such as sea surface temperature fluctuations. Depending on many factors, bleached coral may recover over time or die.
Subsequent monitoring conducted by marine ecologists from WCS, James Cook University (Australia), and Syiah Kuala University (Indonesia) were completed in early August and revealed one of the most rapid and severe coral mortality events ever recorded. The scientists found that 80 percent of some species have died since the initial assessment and more colonies are expected to die within the next few months.
The event is the result of a rise in sea surface temperatures in the Andaman Sea – an area that includes the coasts of Myanmar, Thailand, the Andaman and Nicobar Island, and northwestern Indonesia. According to the National Oceanic and Atmospheric Administration's Coral Hotspots website, temperatures in the region peaked in late May of 2010, when the temperature reached 34 degrees Celsius—4 degrees Celsius higher than long term averages for the area.
"It's a disappointing development particularly in light of the fact that these same corals proved resilient to other disruptions to this ecosystem, including the Indian Ocean Tsunami of 2004," said WCS Indonesia Marine Program Director Dr. Stuart Campbell.
WCS and JCU have been working in the region since March 2005. Surveys conducted in the wake of the Indian Ocean Tsunami in 2004 revealed that the many reefs of Aceh were largely unaffected by this massive disturbance. Indeed, reefs severely damaged by poor land use and destructive fishing prior to the tsunami had recovered dramatically in the intervening years due to improved management. Government and community-managed areas in the region have been remarkably successful at maintaining fish biomass despite ongoing access to the reefs. But the bleaching and mortality in 2010 have rapidly reversed this recovery and will have a profound effect on reef fisheries.
Of particular concern is the scale of the sea surface temperature anomaly which the NOAA website indicates has affected the entire Andaman Sea and beyond. Similar mass bleaching events in 2010 have now been recorded in Sri Lanka, Thailand, Malaysia and many parts of Indonesia.
"If a similar degree of mortality is apparent at other sites in the Andaman Sea this will be the worst bleaching event ever recorded in the region," according to Dr. Andrew Baird of the ARC Centre of Excellence for Coral Reef Studies at JCU. "The destruction of these upstream reefs means recovery is likely to take much longer than before".
"This is a tragedy not only for some of the world's most biodiverse coral reefs, but also for people in the region, many of whom are extremely impoverished and depend on these reefs for their food and livelihoods," said WCS Marine Program Director Dr. Caleb McClennen. "Immediate and intensive management will be required to try and help these reefs, their fisheries and the entire ecosystem recover and adapt. However, coral reefs cannot be protected from the warming ocean temperatures brought on by a changing climate by local actions alone. This is another unfortunate reminder that international efforts to curb the causes and effects of climate change must be made if these sensitive ecosystems and the vulnerable human communities around the world that depend on them are to adapt and endure."
Corals Bleached and Dying in Overheated South Asian Waters
Environmental News Service 16 Aug 10;
BANDA ACEH, Indonesia, August 16, 2010 (ENS) - The rapidly rising temperature of south Asia's Andaman Sea has triggered coral bleaching and die-off that scientists working in Indonesia are calling one of the most rapid and severe coral mortality events ever recorded.
The coral die-off was indentified though monitoring by marine ecologists from the Wildlife Conservation Society based at New York's Bronx Zoo, Australia's James Cook University and Indonesia's Syiah Kuala University in Banda Aceh.
Following up on local reports of coral bleaching in the waters off the northern tip of the Indonesian island of Sumatra, the scientists determined from field studies completed in early August that 80 percent of some species have bleached and died since the initial assessment in May and more colonies are expected to die within the next few months.
Bleaching is a whitening of corals that occurs when colorful algae living within coral tissues are expelled. It is an indication of stress caused by environmental triggers such as sea surface temperature fluctuations.
The scientists say this event is the result of a rise in sea surface temperatures in the Andaman Sea - an area that includes the coasts of Myanmar, Thailand, the Andaman and Nicobar islands, and northwestern Indonesia.
The U.S. National Oceanic and Atmospheric Administration's Coral Hotspots website shows temperatures in the region peaked in late May, when the temperature reached 34 degrees Celsius (93 degrees Fahrenheit) - four degrees Celsius (7.2 degrees F.) higher than long term averages for the area.
"This is a tragedy not only for some of the world's most biodiverse coral reefs, but also for people in the region, many of whom are extremely impoverished and depend on these reefs for their food and livelihoods," said WCS Marine Program Director Dr. Caleb McClennen.
"Immediate and intensive management will be required to try and help these reefs, their fisheries and the entire ecosystem recover and adapt. However, coral reefs cannot be protected from the warming ocean temperatures brought on by a changing climate by local actions alone," said Dr. McClennen.
On Friday NOAA reported that global sea surface temperatures are still climbing. The combined global land and ocean surface temperature made this July the second warmest on record, behind 1998, and the warmest averaged January - July on record, the U.S. agency said.
The worldwide ocean surface temperature was 0.54 degrees C (0.97 degrees F) above the 20th century average of 61.5 degrees F (16.4 degrees C) and the fifth warmest July on record. Although the warmth was most pronounced in the Atlantic Ocean, the general trend affects the corals of the Andaman Sea.
"It's a disappointing development particularly in light of the fact that these same corals proved resilient to other disruptions to this ecosystem, including the Indian Ocean tsunami of 2004," said WCS Indonesia Marine Program Director Dr. Stuart Campbell.
Surveys conducted in the wake of the Indian Ocean tsunami revealed that the many reefs surrounding Aceh were largely unaffected by this massive disturbance.
Scientists found that reefs damaged by poor land use and destructive fishing prior to the tsunami had recovered due to improved management. Government and community-managed areas in the region have been remarkably successful at maintaining fish biomass despite ongoing access to the reefs.
But the bleaching and mortality this year have reversed this recovery and will have a profound effect on reef fisheries, the researchers say.
NOAA indicates warming has affected the entire Andaman Sea and beyond. Similar mass bleaching events in 2010 have now been recorded in Sri Lanka, Thailand, Malaysia and many parts of Indonesia.
"If a similar degree of mortality is apparent at other sites in the Andaman Sea this will be the worst bleaching event ever recorded in the region," said Dr. Andrew Baird of the ARC Centre of Excellence for Coral Reef Studies at James Cook University. "The destruction of these upstream reefs means recovery is likely to take much longer than before."
NOAA reported Friday that the combined global land and ocean surface temperature made this July the second warmest on record, behind 1998, and the warmest averaged January-July on record.
The global average land surface temperature for July and January - July was warmest on record.
The global ocean surface temperature for July was the fifth warmest, and for January - July 2010 was the second warmest on record, behind 1998.
Dr. McClennan warned, "This is another unfortunate reminder that international efforts to curb the causes and effects of climate change must be made if these sensitive ecosystems and the vulnerable human communities around the world that depend on them are to adapt and endure."
Soaring temps cause mass coral killing in Indonesia-study
* Scientists stunned by scale, speed of Aceh coral bleaching
* Coral die-off blow to locals dependent on reefs for income
* Global warming might have played a role -- researcher
David Fogarty, Reuters AlertNet 17 Aug 10;
SINGAPORE, Aug 17 (Reuters) - A dramatic spike in ocean temperatures off Indonesia's Aceh province has killed large areas of coral and scientists fear the event could be much larger than first thought and one of the worst in the region's history.
The coral bleaching -- whitening due to heat driving out the algae living within the coral tissues -- was first reported in May after a surge in temperatures across the Andaman Sea from the northern tip of Sumatra island to Thailand and Myanmar.
An international team of scientists studying the bleaching event found that 80 percent of some species have died since the initial assessment in May.
More coral colonies were expected to die within the next few months and that could spell disaster for local communities reliant on the reefs for food and money from tourism.
"I would predict that what we're seeing in Aceh, which is extraordinary, that similar mortality rates are occurring right the way through the Andaman Sea," said Andrew Baird of James Cook University in Townsville, in the Australian state of Queensland.
If so, that would make it the worst bleaching recorded in the region, said Baird.
Scientists from the Wildlife Conservation Society and Syiah Kuala University in Aceh have also been assessing the damage.
"This one of the most rapid and severe coral mortality events ever recorded," the U.S.-based WCS said in a statement.
It also fits a pattern of climate extremes, from heatwaves to flooding, that have hit many areas of the globe this year.
Between April and late May, sea surface temperatures in the Andaman Sea rose to 34 degrees Celsius or about 4 degrees C above the long-term average, according to the U.S. National Oceanic and Atmospheric Administration's Coral Hotspots website. (See: http://www.osdpd.noaa.gov/ml/ocean/cb/hotspots.html )
SLOW RECOVERY
"Similar mass bleaching events in 2010 have now been recorded in Sri Lanka, Thailand, Malaysia and many parts of Indonesia," the WCS statement said.
Baird, of James Cook University's ARC Centre of Excellence for Coral Reef Studies, told Reuters that climate change could have played a role in the extreme ocean temperatures around Aceh.
"There might be one of these cyclic climate phenomena driving it but it's much more severe than you would predict unless there was something else forcing it, which is almost certainly global warming," he told Reuters on Tuesday.
The bleaching is a blow to local communities in Aceh still recovering from the 2004 tsunami. That disaster caused relatively little damage to reefs and Baird said some areas had showed a dramatic recovery.
Baird said reefs in Indonesia would normally take 5 to 10 years to recover from localised bleaching. But if the event was spread across a much wider area, recovery would take longer.
"I suspect the scale of this event is so large there is unlikely to be many healthy reefs in the rest of Aceh." (Editing by Nick Macfie)