Droste Elise S, Bakker Dorothee C E, Venables Hugh J, Jones Elizabeth M, Meredith Michael P, Dall'Olmo Giorgio, Hoppema Mario, Legge Oliver J, Lee Gareth A, Queste Bastien Y
School of Environmental Sciences, University of East Anglia, Norwich, UK.
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.
Commun Earth Environ. 2025;6(1):457. doi: 10.1038/s43247-025-02395-x. Epub 2025 Jun 18.
Sea-air exchange of carbon dioxide in the Southern Ocean is strongly seasonal, with ocean uptake in summer, which is partly offset by carbon dioxide outgassing in winter. This seasonal balance can shift due to sea ice conditions, inducing interannual variability in the Southern Ocean carbon sink. A decade (2010-2020) of unique, year-round marine carbonate chemistry observations from the Rothera Time Series (West Antarctic Peninsula) reveals that interannual variability in seawater fugacity of carbon dioxide depends on wintertime processes. Sea ice duration controls ocean stratification, which acts as a gateway to the carbon-rich ocean interior. Consequently, years with persistent sea ice cover and high mean winter stratification absorb, on average, 20% more carbon dioxide than years with less sea ice and weaker stratification in winter. Wintertime marine observations are therefore essential to resolve critical processes and reliably quantify interannual variability of the sea-air carbon dioxide flux in seasonally sea ice-covered regions.
南大洋中二氧化碳的海气交换具有强烈的季节性，夏季海洋吸收二氧化碳，而冬季二氧化碳的排放会部分抵消夏季的吸收量。这种季节性平衡可能会因海冰状况而发生变化，从而导致南大洋碳汇的年际变化。罗瑟拉时间序列（南极半岛西部）十年（2010 - 2020年）独特的全年海洋碳酸盐化学观测结果表明，海水中二氧化碳逸度的年际变化取决于冬季过程。海冰持续时间控制着海洋分层，而海洋分层是通往富含碳的海洋内部的通道。因此，与冬季海冰较少且分层较弱的年份相比，海冰持续覆盖且冬季平均分层较高的年份平均吸收的二氧化碳多20%。因此，冬季海洋观测对于解决关键过程以及可靠地量化季节性海冰覆盖区域海气二氧化碳通量的年际变化至关重要。
