Activation of old carbon by erosion of coastal and subsea permafrost in Arctic Siberia-猫眼课题宝

DOI：

10.1038/nature11392

发表时间：

2012-08

期刊：

Nature

影响因子：

64.8

通讯作者：

中科院分区：

综合性期刊1区

文献类型：

作者：

J. Vonk;J. Vonk;L. Sánchez-García;L. Sánchez-García;B. Dongen;B. Dongen;V. Alling;V. Alling;D. Kosmach;A. Charkin;I. Semiletov;I. Semiletov;O. Dudarev;N. Shakhova;N. Shakhova;P. Roos;T. Eglinton;A. Andersson;Ö. Gustafsson

温室气体浓度的未来轨迹取决于气候和大气圈之间的相互作用。北极永久冻土的融化可能会在本世纪向大气中释放大量的碳。沿东西伯利亚北极大陆架（ESAS）约7,000千米长的海岸线露出沿着的古冰复合体沉积物，以及相关的浅海底永久冻土，是两个大型永久冻土碳库，但其解冻和分解的脆弱性在很大程度上尚不清楚。最近的北极变暖比预测的要强烈几度，在ESAS沿海地区尤为明显。因此，迫切需要提高我们对这一相对难以进入的地区的永久冻土碳与气候之间联系的认识。在这里，我们表明，这些冰复合体沉积物中的碳的广泛释放主导了ESAS（世界上最大的大陆架）的沉积碳预算（57 ± 2%），压倒了海洋和表土陆地成分。ESAS表层沉积物中积累的有机碳的双碳同位素组成的逆模型，使用蒙特卡罗模拟来解释不确定性，表明每年有44 ± 10太克的旧碳从冰复合体永久冻土中被激活，比以前的研究所提出的数量级要高。我们估计，大约三分之二（66% ± 16%）的旧碳以二氧化碳的形式逃逸到大气中，其余的则被重新埋藏在陆架沉积物中。随着北极气候变暖的加剧，这些富含碳的更新世海岸线和海底沉积物的热崩塌和侵蚀可能会加速。

The future trajectory of greenhouse gas concentrations depends on interactions between climate and the biogeosphere,. Thawing of Arctic permafrost could release significant amounts of carbon into the atmosphere in this century. Ancient Ice Complex deposits outcropping along the ∼7,000-kilometre-long coastline of the East Siberian Arctic Shelf (ESAS),, and associated shallow subsea permafrost,, are two large pools of permafrost carbon, yet their vulnerabilities towards thawing and decomposition are largely unknown,,. Recent Arctic warming is stronger than has been predicted by several degrees, and is particularly pronounced over the coastal ESAS region,. There is thus a pressing need to improve our understanding of the links between permafrost carbon and climate in this relatively inaccessible region. Here we show that extensive release of carbon from these Ice Complex deposits dominates (57 ± 2 per cent) the sedimentary carbon budget of the ESAS, the world’s largest continental shelf, overwhelming the marine and topsoil terrestrial components. Inverse modelling of the dual-carbon isotope composition of organic carbon accumulating in ESAS surface sediments, using Monte Carlo simulations to account for uncertainties, suggests that 44 ± 10 teragrams of old carbon is activated annually from Ice Complex permafrost, an order of magnitude more than has been suggested by previous studies. We estimate that about two-thirds (66 ± 16 per cent) of this old carbon escapes to the atmosphere as carbon dioxide, with the remainder being re-buried in shelf sediments. Thermal collapse and erosion of these carbon-rich Pleistocene coastline and seafloor deposits may accelerate with Arctic amplification of climate warming,.

Activation of old carbon by erosion of coastal and subsea permafrost in Arctic Siberia

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