Shelled pteropods, microscopic free-swimming sea snails, are widely regarded as indicators for ocean acidification because research has shown that their fragile shells are vulnerable to increasing ocean acidity.
A new study, published in the journal Scientific Reports, shows that pteropods sampled off the coasts of Washington and Oregon made thinner shells than those in offshore waters. Along the coast, upwelling from deeper water layers brings cold, carbon dioxide-rich waters of relatively low pH to the surface. The research, by a team of Dutch and American scientists, found that the shells of pteropods collected in this upwelling region were 37 percent thinner than ones collected offshore.
Sometimes called sea butterflies because of how they appear to flap their “wings” as they swim through the water column, fat-rich pteropods are an important food source for organisms ranging from other plankton to juvenile salmon to whales. They make shells by fixing calcium carbonate in ocean water to form an exoskeleton.
Read more at: NOAA
This close-up image of two pteropods of the species Limacina helicina provides a sense of how fragile the carbonate shells of the tiny sea snails are. (Photo Credit: NOAA Ocean Acidification Program)