Ocean Acidification Already Impacting Snails on West Coast by Dissolving Shells

Ocean acidity is a growing problem as greenhouse gases build up in our atmosphere. Now, the NOAA has discovered the first evidence that acidic waters off of the West Coast are dissolving the shells of tiny free-swimming marine snails. The findings show that ocean acidity could be a huge issue in the future.

The marine snails are called pteropods, and act as a food source for pink salmon, mackerel and herring. This makes the snails an important part of the ecosystem. If fewer pteropods survive, then there's less food for fish higher up the food chain.

Ocean acidification occurs when water absorbs carbon dioxide. As more carbon dioxide enters our atmosphere in the form of greenhouse gases, more of it ends up in the ocean. This change in ocean chemistry can impact sea-dwelling creatures-especially those with calcium carbonate shells. The acidic waters can dissolve shells, which can lower survival rates.

In this case, the researchers tracked the movement of corrosive waters onto the continental shelf form April to September during the upwelling season, when winds bring water rich in carbon dioxide up from depths of about 400 to 600 feet to the surface and onto the continental shelf. They found that the percentage of pteropods in this area with dissolving shells due to ocean acidification has doubled since the pre-industrial era. The scientists also estimated that by 2050, this number may even triple.

"Our findings are the first evidence that a large fraction of the West Coast pteropod population is being affected by ocean acidification," said Nina Bednarsek, one of the researchers, in a news release. "Dissolving coastal pteropod shells point to the need to study how acidification may be affecting the larger marine ecosystem. These nearshore waters provide essential habitat to a great diversity of marine species, including many economically important fish that support coastal economies and provide us with food."

Currently, more research needs to be conducted to assess the extent of ocean acidity and how it might impact other species. As our climate continues to change, it's crucial to understand the possible impacts.