Carbon Uptake Upswing in the Southern Ocean Removes Human-Caused CO2 (VIDEO)

First Posted: Sep 11, 2015 06:42 AM EDT

The Southern Ocean is apparently absorbing more and more CO2 over time. Scientists have found that the carbon sink reinvigorated during the past decade and that there's an upswing in carbon dioxide absorption.

The Southern Ocean seasonally absorbs vast amounts of carbon dioxide (CO2) from the atmosphere and releases it back later in the year. But on an annual average the sea surrounding Antarctica absorb significantly more CO2 than they release. In fact, these seas remove a large part of the CO2 that human activities emit into the atmosphere.

In 2005, though, researchers found that the Southern Ocean carbon sink might have begun to "saturate." Based on models, the scientists suggested that the uptake in carbon had not increased since the late 1980s. This was unexpected since scientists once assumed that there was a direct relationship between the magnitude of the carbon sink and the concentrations of atmospheric CO2.

In this latest study, though, the researchers found that this may not be the case. The scientists analyzed measurements of the concentration of CO2 in the surface waters of the Southern Ocean, from which the flux of CO2 across the air-sea surface could be computed. They also compared the resulting fluxes with estimates based on measurements of atmospheric CO2.

The researchers then used a statistical model of the oceanic CO2 concentrations and then used this model to fill in the gaps.

The researchers found that the Southern Ocean carbon sink began to revive around 2002. Around 2010, its carbon uptake was once again comparable to the level expected on the basis of atmospheric CO2 alone.

The researchers believe that this upswing is due to the air pressure gradient between regions of high and low pressure that caused wind patterns to change.

The findings reveal a bit more about the Southern Ocean, and show how this ocean plays an important role in taking up CO2. With that said, this can change when weather patterns change, which is important to note when thinking of the amount of CO2 in our atmosphere.

The findings are published in the journal Science.