Carbon Dioxide Loading Leading to Unexpected Plankton Growth in Oceans

Plankton is spreading in the North Atlantic much faster than global warming models have predicted. This appears to be due to a much faster than expected "loading" of carbon dioxide into ocean waters from the CO2-laden atmosphere. Normally, carbon dioxide is absorbed into the oceans, which has been reducing the amount in the atmosphere.

When this loading stops, the amount in the atmosphere could rise quickly, but it’s not yet clear whether the plankton growth is good or bad for the planet. Published Thursday in the journal Science, a new study details a tenfold increase in the abundance of a type of floating phytoplankton between 1965 and 2010, and a particularly sharp spike since the late 1990s.

“Something strange is happening here, and it’s happening much more quickly than we thought it should,” said Anand Gnanadesikan, associate professor in the Morton K. Blaustein Department of Earth and Planetary Sciences at Johns Hopkins and one of the study’s five authors. “What is worrisome,” he said, “is that our result points out how little we know about how complex ecosystems function.”

The result highlights the possibility of rapid ecosystem change, suggesting that prevalent models of how these systems respond to climate change may be too conservative, he said. Over the short term, the proliferation of the particular type of phytoplanktons involved, called coccolithophores, may make it harder to remove carbon dioxide from the atmosphere, which is increasingly coming to seem important if we are going to reduce global warming. Over the long term, however, from tens to thousands of years, they help to confine CO2 and confine it in the deep ocean.

The White Cliffs of Dover are made up of the fossils of trillions of coccolithophore skeletons.

The image shows a coccolithophores that has appeared in the Bering Sea.