Jellyfish may be secretly affecting the climate of the oceans: Their movements appear to help change the balance of carbon in the atmosphere, NPR reports. Many jellyfish hide from predators deep underwater during the day and head to the surface at night for a snack, says an oceanographer. When they return, a study in Nature says, they may be carrying carbon dioxide dissolved in surface water down with them.
Ocean mixing—warm surface water mingling with the cold below—plays a big role in the Earth’s temperature. The study is reigniting debate over whether animals can affect the process. But more research is needed to determine whether jellyfish are really climate agents. “What I think we can say at the moment is that it's a plausible idea," says a scientist.