"Sea ice contribution to the air-sea CO2 exchange in the Arctic and Southern Oceans," by SØREN RYSGAARD et al., Tellus B,

Sea ice contribution to the air-sea CO₂ exchange in the Arctic and Southern Oceans

1. SØREN RYSGAARD^1,9,*, 
2. JØRGEN BENDTSEN^1,2, 
3. BRUNO DELILLE³, 
4. GERHARD S. DIECKMANN⁴, 
5. RONNIE N. GLUD^1,5, 
6. HILARY KENNEDY⁶, 
7. JOHN MORTENSEN¹, 
8. STATHYS PAPADIMITRIOU⁶, 
9. DAVID N. THOMAS^6,8, and 
10. JEAN-LOUIS TISON⁷

DOI: 10.1111/j.1600-0889.2011.00571.x

Abstract

Although salt rejection from sea ice is a key process in deep-water formation in ice-covered seas, the concurrent rejection of CO₂ and the subsequent effect on air-sea CO₂ exchange have received little attention. We review the mechanisms by which sea ice directly and indirectly controls the air-sea CO₂ exchange and use recent measurements of inorganic carbon compounds in bulk sea ice to estimate that oceanic CO₂ uptake during the seasonal cycle of sea-ice growth and decay in ice-covered oceanic regions equals almost half of the net atmospheric CO₂ uptake in ice-free polar seas. This sea-ice-driven CO₂ uptake has not been considered so far in estimates of global oceanic CO₂ uptake. Net CO₂ uptake in sea-ice-covered oceans can be driven by: (i) rejection during sea-ice formation and sinking of CO₂-rich brine into intermediate and abyssal oceanic water masses, (ii) blocking of air-sea CO₂ exchange during winter, and (iii) release of CO₂-depleted melt water with excess total alkalinity during sea-ice decay and (iv) biological CO₂ drawdown during primary production in sea ice and surface oceanic waters.

http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0889.2011.00571.x/abstract