Snails and other crustaceans may have trouble forming shells in the future as climate change intensifies, according to a new study published in Frontiers in Marine Science.
The world’s oceans absorb about 30% of the carbon dioxide released into the atmosphere, and the amount of carbon dioxide dissolving into the oceans has drastically increased over the past century as greenhouse gas emissions continue to climb through the ongoing burning of fossil fuels.
This is causing ocean waters to undergo a series of chemical reactions commonly referred to as ocean acidification, which causes carbonate ions to decrease and hydrogen ions to increase, lowering overall pH levels in the process.
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Marine animals that form shells and other hard surfaces, such as coral, depend on carbonate ions as building blocks in their calcification processes. As oceans acidify, that foundational substance is becoming scarce and the very survival of these creatures is being put in jeopardy.
The team of researchers publishing their findings wanted to see how sea snails would cope in marine conditions similar to those expected in the year 2100, so they traveled to a marine volcanic seep off the coast of Japan where carbon dioxide levels are much higher than normal.
There, they collected a number of triton shell gastropods, which are large predatory sea snails.
After conducting tests, the researchers discovered that these sea snails were much smaller than their peers in other regions of the world and their shells were much weaker.
"Ocean acidification is a clear threat to marine life, acting as a stressor for many marine animals,” said Dr. Ben Harvey, assistant professor at the University of Tsukuba's Shimoda Marine Research Center and co-author of the report, in a press release. “Here 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.”
“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,” he added.
As marine conditions around the world approach acidify at similar rates, snails, crabs, lobsters, coral, and many more creatures could decline.
Sometimes sea animals disintegrate in these extreme conditions. Scientists have already found that pteropods, or sea butterflies, dissolve within 45 days of being placed within pH levels similar to those predicted for 2100. Pteropods are a crucial source of food for plankton, whales, salmon, and other creatures.
Coral reefs, meanwhile, are already being wiped out around the world as the oceans warm and acidify.