A study that analyzed data from the Continuous Plankton Recorder (CPR) survey of the North Atlantic Ocean and North Sea since the mid-1960s revealed a tenfold increase in single-cell coccolithophores between the years 1965 and 2010, as well as a large increase in pale-shelled floating phytoplankton in the later half of the 1990s. These results fly in the face of scientific predictions, and the John Hopkins University scientists that carried out the study believe that the findings stem from an increase in the ocean's carbon dioxide levels.
"Something strange is happening here, and it's happening much more quickly than we thought it should," Anand Gnanadesikan, co-author of the study, said in a press release. "What is worrisome, is that our result points out how little we know about how complex ecosystems function."
The results could mean that many of our current ecosystem models may not accurately reflect the rapid changes that are taking place on our planet.
The researchers believe that the rapid spike in the coccolithophore population is due to an increase in carbon dioxide in the ocean, which is supported by various other laboratory studies. Carbon dioxide is believed to be on of the biggest contributors to global warming.
"Our statistical analyses on field data from the CPR point to carbon dioxide as the best predictor of the increase in coccolithophores," said Sara Rivero-Calle, lead author of the study. "The consequences of releasing tons of CO2 over the years are already here and this is just the tip of the iceberg."
Although carbon dioxide is the best contender for the cause of the increase, further research still needs to be conducted until this is certain.
"These clearly represent major shifts in ecosystem type," said Gnanadesikan. "But unless we understand what drives coccolithophore abundance, we can't understand what is driving such shifts. Is it carbon dioxide?"