Thaw Depth Determines Dissolved Organic Carbon Concentration and Biodegradability on the Northern Qinghai-Tibetan Plateau
Thaw Depth Determines Dissolved Organic Carbon Concentration and Biodegradability on the Northern Qinghai-Tibetan Plateau
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解冻深度决定青藏高原北部溶解有机碳浓度和生物降解性
DOI：
10.1002/2017gl075067
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发表时间：
2017-09-28
影响因子：
5.2
通讯作者：
Zhang, T. J.
中科院分区：
文献类型：
--
作者：
Mu, C. C.;Abbott, B. W.;Zhang, T. J.
溶解有机碳（DOC）通量对冻土退化的响应是冻土碳反馈预测的主要不确定性来源之一。对青藏高原北方一个小流域两个完整的水季DOC的输出和性质进行了研究。溶解有机碳浓度和生物降解性下降系统解冻深度增加，通过季节，由于不断变化的碳源和微生物处理的程度。增加DOC的芳香性和C-13-DOC表示转向更多的柠檬酸碳源和更大的停留时间在土壤中到达流网络之前。这些强大的和一致的季节性趋势表明，逐渐活跃层加深可能会减少DOC出口和生物降解性从冻土集水区。由于这些模式是相反的意见，从经历突然的冻土塌陷（热岩溶）的地区，永久冻土降解DOC通量和生物降解性的整体影响可能取决于比例的景观经历逐渐解冻与热岩溶。
The response of dissolved organic carbon (DOC) flux to permafrost degradation is one of the major sources of uncertainty in predicting the permafrost carbon feedback. We investigated DOC export and properties over two complete flow seasons in a catchment on the northern Qinghai-Tibetan Plateau. DOC concentration and biodegradability decreased systematically as thaw depth increased through the season, attributable to changing carbon sources and degree of microbial processing. Increasing DOC aromaticity and C-13-DOC indicated shifts toward more recalcitrant carbon sources and greater residence time in soils prior to reaching the stream network. These strong and consistent seasonal trends suggest that gradual active layer deepening may decrease DOC export and biodegradability from permafrost catchments. Because these patterns are opposite observations from areas experiencing abrupt permafrost collapse (thermokarst), the overall impact of permafrost degradation on DOC flux and biodegradability may depend on the proportion of the landscape experiencing gradual thaw versus thermokarst.