Coral Reefs Putting Up a Good Fight Against Climate Change

Published on December 22nd, 2009 | by

Coral reefs may be more resilient that scientist previously thought, according to Marine scientist Ray Berkelmans, senior marine research scientist with the Australian Institute of Marine Science who has spent  27 years diving along the Keppels, a group of islands off the coast of Queensland, Australia. The coral reefs there can be viewed as a microcosm of and perhaps litmus test for the future of the Great Barrier Reef as a whole.

Photo Credit: LightworksCoral reefs may be more resilient than science had originally thought
Coral reefs may be more resilient than science had originally thought

Berkelman talks about the amazing adaptations of the reef:

“In 2006, we basically saw the [Keppel] corals acclimatise before our eyes. About 95 per cent of the corals were affected, and we think just over a third died, which was a lot more than we had seen before. What surprised us — stunned us, really — is how strongly they have come back. It’s not everywhere . . . we’ve still got reefs struggling. But, generally, you would have to say the coral cover is as good, if not better in places, [as] it was prior to bleaching in 2006, and that has caused us to do a lot of thinking and work on how the corals in the Keppels have coped with bleaching events.”

Coral is very localized and starts to bleach or die if the water temperature changes much. The Keppel coral is said to tolerate water temperatures between 18 and 28.5 degrees Celcius. Essentially there are two opinion camps around the fate of the Great Barrier Reef and coral reefs in general: one side says that a rise to 450ppm of CO2 equals death for coral reefs due to the temperature rise, the other side says that as coral grows in much warmer water elsewhere and is proving resilient in areas like the Keppels, bleaching really means change and adaptation, not death.

Berkelman remains optimistic about the GBR’s survival overall and skeptical of total doomsday:

“There are some areas that are naturally more resilient than others, there are some areas that see warmer temperatures less frequently because of favourable oceanography or other factors . . . we might lose species, and we might lose them at many reefs. The reef would look vastly different, but the reef would still be there. I don’t think there is any doubt about that.”

Peter Ridd, a professor of physics at James Cook University, and fellow reef-resiliency optimist agrees, generally pooh-poohing modern science’s version of reef health:

“Ten years ago, I was told that the coral was going to die from sediment, and we have proved that is complete rubbish,” Ridd says. “They are saying that pesticides are a problem, but when you look at the latest data that is a load of rubbish. They are saying that bleaching is the end of the world, but when you look into it, that is a highly dubious proposition.”

The reef also experienced high percentage bleachings in 1998, 2002 and 2006. In all cases the coral has been largely resilient once temperature rises abated. Will this translate to eventual adaptation? That remains to be seen.

I keep seeing headlines on both sides of every climate change issue- this new study says our models aren’t even close to how bad it will be and this other one says the Earth will be fine. We just don’t know- which is both comforting and, somehow, even more frightening.

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