Coral Distress: Prospects for the long-term survival of coral around the world are grim, said a top government scientist
Image: Photo by Samuel Chow, courtesy Flickr
Unusually warm ocean temperatures this year have led to mass devastation of the world's corals, and prospects for their long-term survival are grim, a top government scientist said yesterday.
"Right now, coral reefs around the world are either bleached, dead from bleaching or trying to recover from bleaching," said C. Mark Eakin, who coordinates the National Oceanic and Atmospheric Administration's Coral Reef Watch. "2010 has been a major, major year of coral bleaching in all of the oceans around the world."
Bleaching occurs when corals expel the microscopic algae that normally live inside their hard skeletons, providing them with food and their bright coloration. Changes in ocean salinity, nutrient runoff and other pollution can cause small-scale bleaching, but scientists say the widespread global bleaching this year is a symptom of unusual ocean warming.
A similar global bleaching event in 1998-1999 destroyed 15 percent of the world's coral reefs. 2010 may not be far behind, Eakin said.
"In 2010, we've been seeing the second global-scale series of bleaching events. They're not as severe as what happened in the late '90s, but it's one of those things -- how bad does it have to be?" he said. "These are both big events. They are really severe."
Scientists have observed reefs bleaching this year in Kuwait, the Maldives, Southeast Asia, the Philippines, central Pacific islands and now the Caribbean, where corals also suffered severe bleaching in 2005.
"Places like the Maldives and reefs in Southeast Asia that were just recovering from '98 are now bleached again," Eakin said. "In Thailand this June, it was frightening. It was hard to find corals that were not bleached."
Rising temperatures are the cause
The question now for scientists is whether the world's reefs will be able to recover from this year's bleaching event, and how they will fare as the world warms.
The 1998-1999 bleaching event was driven by a strong El Niño weather pattern, but El Niño wasn't a major factor in the widespread Caribbean bleaching in 2005 or in the development of this year's bleaching event.
"As temperatures are rising, as the baseline is going up, it doesn't take much of a climate event to push these reefs over the edge," Eakin said.
Two Atlantic Ocean coral species -- elkhorn and staghorn -- are listed as "threatened" under the Endangered Species Act, and NOAA is considering whether an additional 82 coral species also warrant some level of protection under the law because of threats from warming water, ocean acidification and pollution.
Ultimately, creating a safe environment for the world's reefs may require efforts to cut the level of carbon dioxide in the atmosphere to just 350 parts per million, well below the current level of 390 parts per million.
"Even once we stop CO2 emissions, we're looking at another century of warming temperatures and another degree Centigrade rise," Eakin said. "This is something that will be hard on corals even if we start acting now."
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500
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5 Comments
Add CommentThis is not good news. It's very unfortunate because coral reefs are among the most beautiful things on Earth.
Reply | Report Abuse | Link to thisYes we are causing this to happen, yes, it matters, and yes, we can do something about it.
We have affected the natural balance of heat energy on the planet and less of it radiates away because of greenhouse gasses.
If the oceans continue to warm, some things may thrive, but overall we as humans are going to be very unhappy with the results.
". . . even if we start acting now."
Reply | Report Abuse | Link to thisFurther bad news is that we are NOT going to start acting now - despite all evidence that we should have begun years ago.
The presumption that coral reefs are dying due to warming has not been determined as factual. While there has been warming in the last 150 years, it is not been shown to be unprecedented when compared to what we know about previous climate conditions over the last few thousand years.
Reply | Report Abuse | Link to thisIt would be good to keep in mind that one human impact that is unprecedented, and unrelated to warming, and which does correlate quite closely with some coral die-backs is the amount of industrial run-off from the land into the near shore waters where corals are found. Nitrogen rich sediments, as well as increased silt which has been shown to interfer with corals continue at unprecedented rates, unlike the warming we are recording, and even that fails to mention the unprecedented pressures on marine systems that our world's insatiable demand for fish has had on the oceans living realms. Curiously the rise of eco-resorts in the tropic, particularly those near off-shore coral colonies convenient to scuba diving toursists, are introducing frequent incursions of morotized craft into areas rarely visited until now, as well as the introduction of nice grassy (fertilized) lawns around these resorts. If warming alone was the cause one might have expected corals to have died-off long ago and repeatedly and refelcted in the geological/archaeological records.
The article concludes with a statement by Mark Eakin, who coordinates the National Oceanic and Atmospheric Administration's Coral Reef Watch:
Reply | Report Abuse | Link to this"Even once we stop CO2 emissions, we're looking at another century of warming temperatures and another degree Centigrade rise. This is something that will be hard on corals even if we start acting now."
Has anyone suggested we will actually stop co2 emissions any time soon? I suggest we'll have empirical evidence of the relationship between atmospheric co2 and global temperatures over the next few decades if we simply collect the necessary data.
I thought that the reason that warmer waters were killing the coral was well accepted.
Reply | Report Abuse | Link to thisAt a certain temperature point, the corals expel the algae they require to survive in a symbiotic relationship, and once the coral polyps die they take a real long time to grow back relative to human lifespans.
I'm sure corals have died from warm waters many times in the past, and may have survived many ways. They can slowly migrate to cooler areas, maybe some other algae can colonize and perform the same function. I'm sure there are other ways as well, but I'd like to point out that human caused warming seems to be happening too rapidly for the regular ecological mechanisms to cope.