A recent study has uncovered the first evidence that chemical changes in the world’s oceans due to an influx of CO2 is causing the shells of some sea animals to dissolve. The study was conducted by the British Antarctic Survey (BAS) in the Southern Ocean, where researchers found “severe dissolution” of the shells of living marine snails. The survey attributes this phenomenon to a decline in the alkalinity of the water—a decline that, spurred by carbon emissions, is happening faster now than at any point in the last 300 million years.
Photo (cc) Liam Quinn
The British Antarctic Survey’s research, published in the journal Nature Geoscience notes that the marine snails, or pteropods, are a vital part of the Southern Ocean’s ecosystem. Forming a key source of nutrition for fish and birds, as well as a part of the ocean’s carbon cycle, a decline in their population could have a “significant” impact on the food availability and ecosystems of the region.
As the BAS explains this “[o]cean acidification is caused by the uptake of carbon dioxide from the atmosphere emitted as a result of fossil fuel burning,” as the CO2 dissolves into the ocean, it forms carbonic acidic, which causes the water’s alkalinity to decrease. Laboratory tests have previously demonstrated that rapidly increasing ocean acidity could cause damage to animals such as the marine snails, whose shells are comprised of a particular form of calcium carbonate—or aragonite—which is especially sensitive to acidity.
Co-author of the report Dr Geraint Tarling summarized the importance of these groundbreaking findings: “[a]s one of only a few oceanic creatures that build their shells out of aragonite in the polar regions, pteropods are… a good indicator of ecosystem health. The tiny snails do not necessarily die as a result of their shells dissolving, however it may increase their vulnerability to predation and infection consequently having an impact to other parts of the food web.”
Lead image courtesy the British Antarctic Survey