Oysters could hold key to ocean acidification

July 6, 2010 7:53:56 PM PDT
When we hear about global warming we usually think about rising seas and melting ice caps. But it's not only our atmosphere that is experiencing climate change, the chemistry of the ocean is actually changing as well.

It should come as no surprise that scientific research requires strenuous mental exercise. But physical? Just take a look at the trudge through the sludge in Tomales Bay.

Asked if she ever thought sludge work was part of getting a Ph.D., Annalise Hettinger says, "No, that's why I used to scuba dive for my research."

Not anymore. Instead, Hettinger digs for data, literally, with Dr. Eric Sanford. They are collecting native Olympia oysters in beds owned by Todd Friend of the Tomales Bay Oyster Company along Highway 1.

"Apparently there is a real problem on the horizon," says Friend.

From ocean acidification.

"These organisms are real foundations in the ecosystem," says Hettinger. "So if they're not healthy, then the ecosystems aren't healthy."

Ocean acidification is the other part of the climate change equation. It deals not so much with the carbon dioxide in the atmosphere, but carbon dioxide from the atmosphere that settles in the oceans and makes them more acidic.

"The worst case scenario is that under severe conditions of ocean acidification, the shells of things like clams, sea urchins and oysters actually start to dissolve," says Sanford.

But how severe? And how fast? At the UC Davis Bodega Marine Lab, Sanford and his team have launched an elaborate experiment to find out. Tanks simulate future oceans with rising levels of carbon dioxide. They place oyster larvae inside and watch them grow.

"We're seeing really large effects on their shells at these early life history stages," says Hettinger.

Under a microscope, these samples are smaller, less hearty, and probably not capable of evolving as fast as the oceans appear to be changing. Acidification levels have not yet reached a crisis stage, but they could double in the next 100 years.

For oysters and hard-shelled creatures, there would be no escape, not even in an area as remote and pristine area as Tomales Bay.

"It's the loss of an industry, it's a loss of a way of life, really," says Friend.

The loss of a signature delicacy in this place where they lived and thrived, for eons.


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