Ocean Acidification Shrinks Reef Squid Brains

The world's oceans absorb a significant portion of human-released carbon dioxide, leading to increased acidity. This process, known as ocean acidification, is a major side effect of anthropogenic climate change. The dissolved gas reacts with seawater to form carbonic acid, lowering the pH from a historical surface level of 8.2 to about 8.1 today. If climate change continues unabated, the pH could drop to 7.8 by the end of the century. While it has long been established that acidification harms calcifying organisms like mussels, lobsters, crabs, and corals—which struggle to extract calcium carbonate from more acidic water to build their shells—new research highlights a different victim: the reef squid, an animal with an unusually powerful brain. The study suggests that acidification can cause brain shrinkage in reef squid, raising questions about their survival. The findings underscore the far-reaching impacts of ocean acidification beyond shell-building, affecting neural function in cephalopods. The research was reported by Nick Reimer in the German publication 'der Freitag'.