Though climate scientists have long debated the reasons behind the variation in atmospheric levels of carbon dioxide that occur over lengthy periods in Earth's history, the Princeton team may have found a clue to where the answer can be found. In a new research paper, the team reveals that the waters in the Southern Ocean below 60 degrees south latitude, the region that hugs the continent of Antarctica, play a far more significant role than was previously thought in regulating atmospheric carbon, and -- in contrast to past theories -- the waters north of this region do comparably little to regulate it.
"Cold water that wells up regularly from the depths of the Southern Ocean spreads out on the ocean's surface along both sides of this dividing line, and we have found that the water performs two very different functions depending on which side of the line it flows toward," said Irina Marinov, the study's lead author. "While the water north of the line generally spreads nutrients throughout the world's oceans, the second, southward-flowing stream soaks up carbon dioxide, a greenhouse gas, from the air. Such a sharply-defined difference in function has surprised us. It could mean that a change to one side of the cycle might not affect the other as much as we once suspected."
The research team, which also includes Princeton's Jorge Sarmiento as well as the National Oceanic and Atmospheric Administration's Anand Gnanadesikan and Robbie Toggweiler, will publish their results in today's (June 22) issue of the scientific journal, Nature. Marinov, who led the study while working in Sarmiento's lab, is currently pursuing postdoctoral research at the Massachusetts Institute of Technology as a NOAA Fellow in Climate and Global Change.