Mussel shells are getting thinner over the centuries, discover University of Chicago researchers. Comparing shells of live mussels from the Pacific coast with historical mussel shells, almost a millennium old, they realised that these creatures' shells have become excessively thin.
The researchers have stated in Proceedings of the Royal Society B that historical shells more than 1,000 years old are 27 percent thicker than shells today. Thick shells were common till the 1970s, they were 32 percent thicker than today's shells. However, the shells started thinning mysteriously fast after that.
Shells are thinning rapidly due to the speedy acidification of Pacific Ocean. Shockingly, the live mussels that swim through the waters are slowly dissolving into the seawater, which is only the start of "bad news" for the shellfish.
Scientists have collected some shells from other Native American sites in Sand Point, Washington, that were 2150 to 2420 years old. They were found to 94 percent thicker than shells today.
The reason is probably due to the rise in acid levels in the oceans, which may lead to the brittleness of mussels that can even lead to their death, reports Gizmodo Australia.
Mussels, oysters, and certain species of algae are finding it extremely difficult to manufacture calcium carbonate shells and skeletons in an environment of acidification. It gives early signs of ocean acidification affecting marine life.
"Archival material provided by past researchers, the Makah Tribal Nation, and the Olympic National Park allowed us to document this intriguing and concerning pattern in shell thickness," lead author of the study and professor of ecology and evolution, Cathy Pfister, said in a University of Chicago statement.
Another reason could be the alteration of the food supply in the oceans.
Earlier, Pfister and her colleagues recorded that the dipping pH levels in waters around Tatoosh Island, near Washington coast, has led to the thinning of shells. They analysed the oxygen and carbon isotopes extracted from modern mussel shells collected by a local Makah tribe between 668 and 1008 A.D. as well as those gathered in the 1970s.
