The research team collects several samples from each stop along the route to measure the chemical composition of the ocean water. (Photo by Ann Dornfeld)
We hear a lot about carbon dioxide in the atmosphere. But half of all man-made CO2 is stored in the world’s oceans. When CO2 mixes with water, it increases the oceans’ acidity. As Ann Dornfeld reports, that acidification is moving closer toward the oceans’ fragile coastal areas:
Transcript
We hear a lot about carbon dioxide in the atmosphere. But half of all man-made CO2 is stored in the world’s oceans. When CO2 mixes with water, it increases the oceans’ acidity. As Ann Dornfeld reports, that acidification is moving closer toward the oceans’ fragile coastal areas:
If you’ve ever wondered why sparkling water tastes tangy, instead of just bubbly – it’s because of carbonic acid. That’s what’s produced when carbon dioxide is added to water. Some of the CO2 in the world’s oceans is natural, from things like decaying algae. But the oceans also soak up CO2 produced by cars and factories. Once CO2 is absorbed into the ocean, it sinks to the coldest, deepest water for long-term storage.
Chemical oceanographers at Oregon State University are monitoring the chemical composition of the Pacific Ocean to see where the carbon is being stored. On a research vessel several miles off the coast, they lower a series of bottles down to the ocean floor on a winch.
(sound of winches)
Scientists have expected that upwellings would eventually bring some of that CO2 to the coastal zones that are home to a huge array of marine life. They thought it would take a century or more. But a recent study, published in the journal Science, found acidic water fewer than 20 miles off the Pacific Coast.
Grad student Rachel Holzer says that’s alarming.
“The ocean is normally at a very stable pH. It is a buffered system, which means it is not very easy for the pH to change. But recently there’s been evidence that ocean acidification is happening, meaning that the pH is dropping. And that can be very harmful to biological life of all different types.”
Corrosive water can dissolve the calcium carbonate shells of barnacles, mussels, oysters and clams. Coral reefs are also calcium carbonate. So are a lot of planktonic species, including terrapods. Those make up about half of the diet of young salmon.
Burke Hales co-authored the latest study. He’s an Associate Professor of Chemical Oceanography at Oregon State.
“The question is how are these organisms going to respond, you know? Do their shells dissolve, do they just not grow as quickly? If their shells are negatively impacted, are the organisms themselves negatively impacted? And if the organisms are negatively impacted, how does that cascade through the food web?”
Hales says stopping ocean acidification would be extremely difficult, if not impossible.
“There are people who have talked about going out in the ocean and spraying sodium carbonate pellets into the water, which would dissolve and neutralize some of the carbonic acid. Sort of like when you take a Tums, that’s the active ingredient in Tums is calcium carbonate. That’s one idea that’s been proposed. It’s really, really speculative that that would work.”
What’s more, Hales says the process of hauling all of that ocean antacid out to sea and dispersing it could produce as much CO2 as it would neutralize.
“It is depressing. We wish things weren’t this way and moving sort of irreversibly towards worse conditions. But we also know that the oceans do have a lot of ability to adapt. And what we don’t know yet is exactly how this is gonna play out.”
One thing scientists do know is that the acidification has just begun. The corrosive water they found right off the Pacific Coast was from carbon dioxide released about 50 years ago. And over the last half century, CO2 production has only increased.
For the Environment Report, I’m Ann Dornfeld.
