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Mussels Lose Out As Carbon Dioxide Changes Ocean
The eroded and gaping shells on these mussels may be signs of stress from increasing ocean acidity. Courtesy C. A. Pfister hide caption
The eroded and gaping shells on these mussels may be signs of stress from increasing ocean acidity.
Courtesy C. A. Pfister
The waters around Tatoosh Island, Wash., are becoming acidic 10 times faster than expected, according to a new study. The increasing acidity is changing the ecosystem around the island, with 10 to 20 percent of its mussels replaced by acid-tolerant algae. Courtesy C. A. Pfister hide caption
The waters around Tatoosh Island, Wash., are becoming acidic 10 times faster than expected, according to a new study. The increasing acidity is changing the ecosystem around the island, with 10 to 20 percent of its mussels replaced by acid-tolerant algae.
Courtesy C. A. PfisterIs The Planet's Carbon Sink Getting Too Full?
You can't talk about climate change without talking about the ocean. Seas dominate life on Earth. Dropping a person into the ocean is the size equivalent of an ant being on Mount Everest.
But the ocean's role in keeping the Earth habitable is often overlooked. It absorbs about half of all carbon dioxide that is released into the air by burning fossil fuels. But as the Earth warms up, the ocean is losing this ability.
All the carbon dioxide pouring into the atmosphere is making the oceans more acidic — and those effects appear to be striking very close to home.
Scientists have been fretting about what ocean acid will do to coral reefs and certain species of plankton. And a new study now documents a startling and rapid change in ocean acid on an island just off the coast of Washington state.
Ocean chemistry measured from Tatoosh Island found that the ocean there is becoming acidic 10 times faster than expected, according to a study published in the Proceedings of the National Academy of Sciences. And the study's author J. Timothy Wootton says the island's ecosystem is changing rapidly as a result.
During an eight-year period, he says, 10 to 20 percent of the mussels on the island have been replaced by acid-tolerant algae.
"When we project where these shifts are going in the long run, they're actually pretty alarming," Wootton says.
Given this trend, he expects 60 to 70 percent of the mussels on the island to disappear in the coming decades.
"The demise of mussels as a dominant species is potentially a pretty big deal," Wootton says. Mussels provide shelter for many animals that live along the tide line. They form a key part of the food web that includes the fish we eat.
Wootton isn't sure why the acidity changed so rapidly on this island. One lesson, though, is that ocean chemistry doesn't change uniformly over the entire planet — there are hot spots. No other studies along the Pacific coast have been monitoring acidity regularly, as this study did, so it's not clear how widespread the phenomenon is.
It's also not clear what we can do about it. Marine scientist Jane Lubchenco at Oregon State University says that even if the world abruptly shifts away from fossil fuels — and stops emitting billions of tons of carbon dioxide into the atmosphere every year — the oceans will continue to soak up carbon dioxide from the air and become more acidic.
Lubchenco says that means other ways must be found to help marine organisms survive this global threat. She recommends protecting marine life by reducing overfishing, cutting back on nutrient runoff, and creating marine reserves to protect the most valuable and vulnerable marine ecosystems.