Carbon export from mountain forests enhanced by earthquake-triggered landslides over millennia
Carbon export from mountain forests enhanced by earthquake-triggered landslides over millennia
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DOI：
10.1038/s41561-018-0216-3
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发表时间：
2018-10-01
影响因子：
18.3
通讯作者：
Densmore, Alexander L.
中科院分区：
文献类型：
--
作者：
Frith, Nicole, V;Hilton, Robert G.;Densmore, Alexander L.
地震期间地面的快速加速度可能引发山体滑坡，破坏山林，并从土壤和植被中收集碳。虽然在人类的时间尺度上并不常见，但这些同震滑坡可以确定几个世纪到几千年的地貌过程。然而，地震和山体滑坡对生物圈碳输出的长期影响仍然没有得到很好的限制。在这里，我们研究了沉积填充的帕林加湖，新西兰，这是由一条河流排水陡峭的山脉近阿尔卑斯断层。碳同位素显示，在过去类似1,100年的四次大地震之后，生物圈碳的积累率增加，这可能反映了深层滑坡侵蚀的土壤来源的碳的输送。累积起来，这些地震动员的碳脉冲占记录长度的23 +/- 5%，但占核心生物圈碳的43 +/- 5%。滑坡模拟表明，每次地震可能会侵蚀1400 +/-500万吨碳（MtC）。我们的研究结果支持活动构造与地表碳循环之间的联系，并表明大地震可以显着促进数千年来山林的碳输出。
Rapid ground accelerations during earthquakes can trigger landslides that disturb mountain forests and harvest carbon from soils and vegetation. Although infrequent over human timescales, these co-seismic landslides can set the rates of geomorphic processes over centuries to millennia. However, the long-term impacts of earthquakes and landslides on carbon export from the biosphere remain poorly constrained. Here, we examine the sedimentary fill of Lake Paringa, New Zealand, which is fed by a river draining steep mountains proximal to the Alpine Fault. Carbon isotopes reveal enhanced accumulation rates of biospheric carbon after four large earthquakes over the past similar to 1,100 years, probably reflecting delivery of soil-derived carbon eroded by deep-seated landslides. Cumulatively these pulses of earthquake-mobilized carbon represent 23 +/- 5% of the record length, but account for 43 +/- 5% of the biospheric carbon in the core. Landslide simulations suggest that 14 +/- 5 million tonnes of carbon (MtC) could be eroded in each earthquake. Our findings support a link between active tectonics and the surface carbon cycle and suggest that large earthquakes can significantly contribute to carbon export from mountain forests over millennia.