Surface exposure to sunlight stimulates CO2 release from permafrost soil carbon in the Arctic
Surface exposure to sunlight stimulates CO2 release from permafrost soil carbon in the Arctic
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DOI：
10.1073/pnas.1214104110
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发表时间：
2013-02-26
影响因子：
11.1
通讯作者：
Kling, George W.
中科院分区：
文献类型：
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作者：
Cory, Rose M.;Crump, Byron C.;Kling, George W.
最近的气候变化导致北极土壤温度升高，大面积的永久冻土融化，使先前冻结的碳得以进行微生物呼吸。此外，冰融化导致土壤不稳定，导致热岩溶破坏增加，使埋藏的碳暴露出来，并将溶解的有机碳（DOC）释放到地表水中。一旦暴露，这个C的命运是未知的，但将取决于它对阳光和微生物攻击的反应，以及表面可用的光。在这项研究中，我们对热岩溶活动区域释放的水进行了处理，结果表明，与保持黑暗时相比，新暴露的 DOC 在暴露于紫外线时更容易被微生物转化为 CO2 40% 以上。当整合到接收河流的水柱上时，这种敏感性转化为浑浊河流和 DOC 颜色河流中光刺激细菌活动平均分别占总面积活动的 11% 到 40%。 DOC 对微生物的不稳定性范围似乎取决于之前的光照，这意味着阳光可能充当冷冻碳储存转化为大气中碳气体的放大因素。
Recent climate change has increased arctic soil temperatures and thawed large areas of permafrost, allowing for microbial respiration of previously frozen C. Furthermore, soil destabilization from melting ice has caused an increase in thermokarst failures that expose buried C and release dissolved organic C (DOC) to surface waters. Once exposed, the fate of this C is unknown but will depend on its reactivity to sunlight and microbial attack, and the light available at the surface. In this study we manipulated water released from areas of thermokarst activity to show that newly exposed DOC is >40% more susceptible to microbial conversion to CO2 when exposed to UV light than when kept dark. When integrated over the water column of receiving rivers, this susceptibility translates to the light-stimulated bacterial activity being on average from 11% to 40% of the total areal activity in turbid versus DOC-colored rivers, respectively. The range of DOC lability to microbes seems to depend on prior light exposure, implying that sunlight may act as an amplification factor in the conversion of frozen C stores to C gases in the atmosphere.