The photograph shows the effects of lower pH levels, or increased acidity, on the shells of triton shell sea snails. Shells formed near oceanic vents, where acidity levels are elevated, were smaller, thinner and less dense. Photo by Ben Harvey/University of Tsukuba
Oct. 15 (UPI) -- Rising acidity levels in the world's oceans are disrupting the shell-making abilities of the marine gastropods. According to a new study, the shells of triton shell sea snails are smaller, thinner and less dense in regions where acidity levels are accelerating.
Several studies have detailed the impacts of rising acidity levels of the calcification process. As pH levels decrease, bivalves, gastropods and other marine shell-makers struggle to control calcification.
When scientists in England and Japan surveyed triton shell sea snails exposed to increased acidity levels, they found specimens were a third of the size of their relatives elsewhere. The shells of the normally large sea snail predators were also thinner and less dense.
Acidity levels are greater near ocean floor volcanic vents off the coast of Japan. As carbon dioxide bubbles up through the vents, pH levels decrease. Models suggest much of Earth's oceans will experience acidity levels comparable to those measured near the vents in the future.
Scientists used CT scans to precisely measure the shells of sea snails raised near the vents. Researchers compared the compromised shells to the shells of healthy snails raised elsewhere.
"We found that the ability of the triton shells to produce and maintain their shells was hindered by ocean acidification, with the corrosive seawater making them smoother, thinner, and less dense," Ben Harvey, an assistant professor at the University of Tsukuba's Shimoda Marine Research Center, said in a news release.
As the CT scans revealed, some thinning shells left portions of the sea snail's flesh exposed. The discovery suggests the sea snail's shells are actively dissolving as a result of elevated acidity levels.
Scientists warn the problem will become more widespread as Earth's oceans takes up more excess carbon.
"The extensive dissolution of their shells has profound consequences for calcified animals into the future as it is not something they can biologically control, suggesting that some calcified species might be unable to adapt to the acidified seawater if carbon dioxide emissions continue to rise unchecked," Harvey said.
Researchers detailed their survey of triton shell sea snails in the journal Frontiers in Marine Science.