Our oceans, teaming with life and a rich source of food, are changing.
Absorbing half of the world’s carbon emissions — in excess of hundreds of millions of tons — is enough to potentially change marine life as we know it.
And what may seem like a subtle shift in chemistry to the average person could spell disaster. A lab here is providing clues about what’s in store, using king crabs, which are the ocean’s equivalent of a canary in the coal mine.
“If they are impacted by ocean acidification, we are talking about the entire food chain being impacted from the bottom up,” said Dr. Bob Foy with the Kodiak Fisheries Research Center.
In addition to the carbon dioxide pumped into the atmosphere by humans, oceans have soaked up carbon naturally over eons. The question is at what point does the ocean’s chemistry become dangerously unbalanced?
Carbon-loaded water is more acidic, which is also more corrosive. And for animals that make shells, that’s potentially a huge problem.
“If you were to take a shell and stick it in a can of Coke it will dissolve because of the carbon dioxide that’s forced into the can. It’s the same thing that’s happening in the environment right now,” Foy said.
Researchers are raising crabs in different carbon-infused environments and taking note of the effects.
“What we’re looking for is both the thickness of that shell and then when she molts we’ll be looking at her ability to form the new shell,” Foy said.
Scientists already know ocean acidification impacts the way the crabs grow and molt, but what else does it do?
“The question is what happens before it completely dissolves — does it become available to predation?” Foy said. “You know there is a reason they have these shells. If the shell starts to dissolve and gets weak, does that make them easier food for a big cod or a flat fish or something?”
With ocean life so delicately intertwined, scientists say changes in just one animal can trigger a cascade of effects across the entire chain of life, and they’re hoping Alaska’s king crabs will help decode what’s yet to come.
By the end of this century the oceans are predicted to be 150 times more acidic than pre-industrial levels. Right now they’re 30 percent higher.
The work at Kodiak is to determine where the tipping point for species survivability may be, in hopes of giving people time to prepare for the changes ahead.
This could also impact salmon and the fishing industry in serious ways. One lawmaker called it global warming’s “evil twin.”
Similar carbon dioxide tests performed on small snails showed that when exposed to the levels expected by the end of the century their shells dissolved within 48 hours.
Pink salmon eat those snails, so it really has the potential to have a huge ripple effect across the balance of life in the ocean.
Jill Burke, KTUU.COM, 27 April 2009. Article.
