One of the main, and overlooked, aspects of
pumping over 30 billion tons of CO2 into the atmosphere is ocean acidification. As CO2 levels go up in the atmosphere, greater amounts of CO2 are absorbed by the ocean. The CO2 combines with H2O and a Carbonate ion (CO3) to make 2 bicarbonate ions (2 HCO3), pushing the acidity of the ocean down and threatening to destroy the shells of many organisms as the picture above shows.
While this is certainly dire news for oysters, clams and pretty much any hard shelled critter in the seas, corals were seen as the biggest losers of ocean acidification. No only would their shells dissolve, their algae symbiotes would die off or leave the host.
Then again, maybe not:
Cohen says this raucous coral ecosystem shouldn’t even exist. The water is way too acidic.
“We started taking water samples,” she says, casting back to an earlier visit here. “We analyzed them, and we couldn’t believe it. Of the 17 coral reef systems (around the world) that we’ve been monitoring, this is the most acidic site that we’ve found.”
The higher acidity of the water here is natural, but it defies all expectations. Conventional wisdom is that corals don’t like acidic water, and the water in Nikko Bay is acidic enough that it should dissolve the animals’ calcium carbonate skeletons.
Even weirder, Cohen says, is that the acidity goes up as you move from the barrier reefs offshore into Palau’s island bays, and that as that happens, the coral cover and the coral diversity increase as well.
This suggests that the corals may have an ability to to calcify in more acidic waters, or that they have adapted to low carbonate levels.
This backs up research showing corals can adapt to higher temperature and levels of CO2.
Kathryn Shamberger of the Woods Hole Oceanographic Institution in Massachusetts and her colleagues were surprised to find that coral reefs around the Palau archipelago in the west Pacific were dense and diverse – even though the pH of the water and the amount of carbonate were unusually low (Geophysical Research Letters, doi.org/qnj).
This suggests that the corals have a way to calcify in more acidic waters, says Philip Munday at James Cook University in Brisbane, Australia, or that they have adapted to low carbonate levels.
Of Note: I originally linked/quoted the above to CO2science.org, a climate skeptic site. The update below explains my error.
These reefs should move to the top of the global coral conservation list, not just for conservation purposes, but to find out how these corals are able to thrive in acidic waters. By the end of the century, the world's oceans are likely to be as acidic as Palau's Nikko Bay. Start by lobbying your Congressional Representative, especially if they are part of the Ocean Caucus as Sen. Cardin of MD is, to push for larger marine sanctuaries.
Fri Jan 03, 2014 at 7:53 AM PT: afisher, in the comments, pointed out that I used a link to a climate skeptic site, CO2 Science.org. I originally heard the story on PRI, and other sites had similar info.
So to make amends, here's other sites to check out for the same info:
Geophysical Research Letters - Diverse Coral Communities in Naturally Acidified Waters of a Western Pacific Reef - "[In the] Palau's Rock Island bays, where acidification levels approach those projected for the western tropical Pacific open ocean by 2100. Nevertheless, coral diversity, cover and calcification rates are maintained across this natural acidification gradient. Identifying the combination of biological and environmental factors that enable these communities to persist could provide important insights into the future of coral reefs under anthropogenic acidification."
Nature.com - Partial offsets in ocean acidification from changing coral reef biogeochemistry -
"[W]e show that a range of projected biogeochemical responses of coral reef communities to ocean acidification by the end of this century could partially offset changes in seawater pH and Ωa by an average of 12–24% and 15–31%, respectively."
Sorry for the initial error. The skeptic site likely saw research of corals adapting to excess CO2 and used it as the usual "oh look, climate change is no biggie to life", the same way we've heard that plants and crops will do great under excess CO2 (after exceeding a certain level, they don't).