By Chase Martin
A recent study published in Science found a tenfold increase in coccolithophore plankton in the North Atlantic and North Sea. Between the years 1965-2010, these organisms experienced a boom in growth, with a curious sharp spike since the late 1990s.
The paper is the result of an analysis of an ongoing study of Continuous Plankton Recorder survey data that started in the early 1930s, in which commercial ships tow plankton-catching devices as they travel their normal routes.
Coccolithophores are single-celled phytoplankton that are distinguished by their shell-like cluster of chalk disks, and the surprising increase in their numbers defies previous scientific predictions. Scientists might have originally speculated that ocean acidification from higher carbon dioxide levels would suppress coccolithophores, whose shells are made of chalk. These results seem to disagree.
“Something strange is happening here, and it’s happening much more quickly than we thought it should,” said Anand Gnanadesikan of Johns Hopkins, one of the study’s authors, in a news release.
The result is a sign of possible rapid ecosystem change, and suggests that previous predictions of change related to increased carbon dioxide levels may be too moderate. This is worrying, because it shows how little we actually know about the way ecosystems, especially complex ones, operate.
“The consequences of releasing tons of CO2 over the years are already here and this is just the tip of the iceberg,” said Sara Rivero-Calle, lead author of the study. She also said that the analysis of the recorder data suggests that current levels of CO2 in the ocean are the main predictor of the thriving plankton.
Historically, coccolithophores have been more abundant during Earth’s warmer periods with high carbon dioxide levels. Massive deposits of these organisms, such as the White Cliffs of Dover, give clues to past climate cycles and environmental shifts. Based on the science at hand, the data seems to suggest where the Earth’s climate is headed, with the coccolithophores as the metaphorical canary in the coalmine.
“These clearly represent major shifts in ecosystem type,” Gnanadesikan said. “But unless we understand what drives coccolithophore abundance, we can’t understand what is driving such shifts. Is it carbon dioxide?”
To learn more:
- Read the JHU news release: Rapid Plankton Growth in Ocean Seen as Sign of Carbon Dioxide Loading
- Read the study abstract: Multidecadal increase in North Atlantic coccolithophores and the potential role of rising CO2
Chase Martin is a science communicator and graduate of Scripps Institution of Oceanography who lives and works in Washington, D.C.
Copyright © 2015 by Marine Science Today, a publication of Marine Science Today LLC.