Deep Yedoma permafrost: A synthesis of depositional characteristics and carbon vulnerability
Deep Yedoma permafrost: A synthesis of depositional characteristics and carbon vulnerability
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DOI：
10.1016/j.earscirev.2017.07.007
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发表时间：
2017-09-01
影响因子：
12.1
通讯作者：
Veremeeva, Alexandra
中科院分区：
文献类型：
--
作者：
Strauss, Jens;Schirrmeister, Lutz;Veremeeva, Alexandra
永久冻土是北极陆地的一个显著特征，易受气候变暖的影响。多年冻土以不同的方式退化，包括季节性解冻表面的加深和局部但快速发展的深融特征。更新世富含冰的永久冻土带同生冰楔，称为Yedoma沉积物，广泛分布于西伯利亚、阿拉斯加和加拿大育空地区，可能特别容易发生快速解冻过程。这种沉积物中的冻结有机物可以在短时间内重新动员，并有助于碳循环的气候反馈。在这里，我们综合的特点和脆弱性的Yedoma存款综合研究Yedoma的起源和相关的有机碳库。我们认为，Yedoma存款积累冰缘风化，运输和沉积动力学在非冰川地区在晚更新世，直到晚冰期变暖的开始。沉积物的形成是由于风成、崩积、不稳定和冲积沉积以及同时的地面冰堆积的组合。我们在Yedoma中发现了高达130亿吨的有机碳，其中部分保存完好，解冻后可快速分解。根据孵化实验，高达10%的Yedoma碳被认为是特别可分解的，并可能在解冻时释放。Yedoma的大量地面冰使其非常容易受到热岩溶和热侵蚀过程等干扰。预计在未来气候变暖的情况下，永久冻土碳的动员将增加。我们的综合结果强调，需要在下一代地球系统模型中核算Yedoma碳储量，以更完整地表示冻土碳反馈。
Permafrost is a distinct feature of the terrestrial Arctic and is vulnerable to climate warming. Permafrost degrades in different ways, including deepening of a seasonally unfrozen surface and localized but rapid development of deep thaw features. Pleistocene ice-rich permafrost with syngenetic ice-wedges, termed Yedoma deposits, are widespread in Siberia, Alaska, and Yukon, Canada and may be especially prone to rapid-thaw processes. Freeze-locked organic matter in such deposits can be re-mobilized on short time-scales and contribute to a carbon-cycle climate feedback. Here we synthesize the characteristics and vulnerability of Yedoma deposits by synthesizing studies on the Yedoma origin and the associated organic carbon pool. We suggest that Yedoma deposits accumulated under periglacial weathering, transport, and deposition dynamics in non-glaciated regions during the late Pleistocene until the beginning of late glacial warming. The deposits formed due to a combination of aeolian, colluvial, nival, and alluvial deposition and simultaneous ground ice accumulation. We found up to 130 gigatons organic carbon in Yedoma, parts of which are well-preserved and available for fast decomposition after thaw. Based on incubation experiments, up to 10% of the Yedoma carbon is considered especially decomposable and may be released upon thaw. The substantial amount of ground ice in Yedoma makes it highly vulnerable to disturbances such as thermokarst and thermo-erosion processes. Mobilization of permafrost carbon is expected to increase under future climate warming. Our synthesis results underline the need of accounting for Yedoma carbon stocks in next generation Earth-System-Models for a more complete representation of the permafrost-carbon feedback.