Glacier tongue calving reduced dense water formation and enhanced carbon uptake
Glacier tongue calving reduced dense water formation and enhanced carbon uptake
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DOI：
10.1002/grl.50178
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发表时间：
2013-03
影响因子：
5.2
通讯作者：
E. Shadwick;S. Rintoul;B. Tilbrook;G. Williams;N. Young;A. Fraser;H. Marchant;Jodie Smith;T. Tamura
中科院分区：
文献类型：
--
作者：
E. Shadwick;S. Rintoul;B. Tilbrook;G. Williams;N. Young;A. Fraser;H. Marchant;Jodie Smith;T. Tamura
形成于Mertz Polynya的密集陆架水供应全球翻转环流的下肢，使深海印度洋和太平洋通风。2010年2月默茨冰川舌（MGT）的崩解改变了冰的区域分布，并减少了冰穴的大小和活动。密集的陆架水的盐度和密度在产犊后突然下降，这与冰间湖海冰形成的减少是一致的。冰山B9 B和MGT的运动释放了多年的厚海冰的破裂和融化，使近地表沃茨清新。融水的输入可能增强了光和铁的可用性，支持硅藻水华，使碳吸收量相对于预分解条件增加了一倍。增强生物碳下降增加碳酸盐饱和状态，超过稀释融水输入。这些观测结果突出了密集水形成、生物生产力和碳输出对南极冰盖变化的敏感性。
Dense shelf water formed in the Mertz Polynya supplies the lower limb of the global overturning circulation, ventilating the abyssal Indian and Pacific Oceans. Calving of the Mertz Glacier Tongue (MGT) in February 2010 altered the regional distribution of ice and reduced the size and activity of the polynya. The salinity and density of dense shelf water declined abruptly after calving, consistent with a reduction of sea ice formation in the polynya. Breakout and melt of thick multiyear sea ice released by the movement of iceberg B9B and the MGT freshened near‐surface waters. The input of meltwater likely enhanced the availability of light and iron, supporting a diatom bloom that doubled carbon uptake relative to precalving conditions. The enhanced biological carbon drawdown increased the carbonate saturation state, outweighing dilution by meltwater input. These observations highlight the sensitivity of dense water formation, biological productivity, and carbon export to changes in the Antarctic icescape.