Wednesday, October 17, 2007

Hope that Corals Will Withstand Global Warming's Impact

Besides global warming, burning fossil fuels also cause CO2 levels in the ocean to become higher which causes them to be more acidic. This rising ocean acidity has a negative effect on the ability of corals to build their calcium carbonate skeletons. So much so that it could cause coral reefs to waste away.

But it did make me wonder, how did coral exist millions of years ago when CO2 levels were much higher? And here is my answer:

Jaroslaw Stolarski and his colleagues found that ancient corals were able to alter the way they built their aragonite skeletons to adjust to their increasingly acidic surroundings - opening the door to the possibility that modern corals could do the same under similar conditions.

The fossilized corals they studied - belonging to the genus Coelosmilia, which were commonly found during the Cretaceous period - had calcite skeletons, a form of calcium carbonate less susceptible to the corrosive effects of a lower pH (as opposed to aragonite). "We now have many different arguments to prove that these corals were actually made originally out of calcite—and not just aragonite that was transformed after the coral died and become fossilized ... There was great biological variability among the corals, and some of them adjusted perfectly to the prevailing geochemical situation," said Stolarski.

If calcite skeletons were more effective at dealing with an increasingly acidic ocean, why were there still so many aragonite skeletons? According to Stephen Cairns, a research zoologist at the Smithsonian's National Museum of Natural History, it may be because corals evolved the ability to switch their skeletons from one form to the other: "This study has opened the door to the possibility that coral skeletons can potentially change back and forth from aragonite to calcite."
Interesting. Now we just need to toss these corals in the Biosphere, pump in the additional CO2 and see if they can replicate the behavior.

via TreeHugger


Audacious Epigone said...

The implication is a lot wider than just for corals. If warming trends continue, expect not only countless adaptations to occur, but also the emergence of new species. The idea that the black bear might (already is?) split into multiple species due to increasing differences in habitat between say, New Hampshire and the Rockies, is rarely considered, while the loss of polar bear habitat is brought up ad nauseum.

Fat Knowledge said...

Yes, interesting point. When I get a chance I am going to write a post "Why this extinction is different", hitting on a similar concept. The previous mass extinctions of species all went along with massive losses of living organisms. When the asteroid wiped out the dinosaurs, it vastly reduced the livability of the planet.

With global warming and the impact of humans, it appears that the net primary productivity of the land isn't decreasing. So, it isn't so much that we are losing life on earth as much as we are consolidating it into fewer species. A few species grow to enormous populations (humans, cows, chickens and pigs), while many other ones die out. A good example of this is Hawaii, where they lead the country in extinctions, but it is still bustling with life.

But, that all assumes that global warming doesn't occur too fast for species to adapt. I don't know for sure on that, and unfortunately I think we will have to play it out before we know for sure.

Audacious Epigone said...


Right, but we never acknowledge the emergence of new species. I'm not scientically literate to know why exactly, since we keep coming up with new 'sub species'. Is it partly political?

Fat Knowledge said...


My guess is that it isn't political as much as just takes a long time before you would consider a species to be new. I would think it would be on the order of 50 generations of isolation before you could really call them a different species.

But, the definition of a species is kind of vague, and whether it is a new species or a new sub-species, I don't know how you determine that.

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