Rising carbon dioxide levels in the ocean may have negative effects on the ecosystems that inhabit them. Researchers from the Scripps Institution of Oceanography, USA exposed fish to high levels of carbon dioxide causing them to experience an abnormally large growth of their ear bones or otoliths. Ear bones are vital to fish orientation and general movement.
“At this point one doesn’t know what the effects are in terms of anything damaging to the behaviour or the survival of the fish with larger otoliths,” said David Checkley, a Scripps Oceanography professor. “The assumption is that if you tweak them in a certain way it’s going to change the dynamics of how the otolith helps the fish stay upright, navigate and survive.”
With carbon dioxide levels rising due to fossil fuel burning and other human activities, the oceans have become more acidic in recent years. Further research will focus on whether other fish are similarly affected, if the large otoliths cause any long-term negative damage and effects on other shell-forming creatures and corals.
In addition to aiding movement, otoliths determine the age of fish, because they grow in increments similar to tree rings. The research was published in Science last week.
