Uptake and sequestration of atmospheric CO2 in the Labrador Sea deep convection region

The Labrador Sea is an important area of deep water formation and is hypothesized to be a significant sink for atmospheric CO2 to the deep ocean. Here we examine the dynamics of the CO2 system in the Labrador Sea using time-series data obtained from instrumentation deployed on a mooring near the former Ocean Weather Station Bravo. A 1-D model is used to determine the air-sea CO2 uptake and penetration of the CO2 into intermediate waters. The results support that mixed-layer pCO(2) remained undersaturated throughout most of the year, ranging from 220 mu atm in midsummer to 375 matm in the late spring. Net community production in the summer offset the increase in pCO(2) expected from heating and air-sea uptake. In the fall and winter, cooling counterbalanced a predicted increase in pCO(2) from vertical convection and air-sea uptake. The predicted annual mean air to sea flux was 4.6 mol m(-2) yr(-1) resulting in an annual uptake of 0.011 +/- 0.005 Pg C from the atmosphere within the convection region. In 2001, approximately half of the atmospheric CO2 penetrated below 500 m due to deep convection.