Effects of permafrost thawing on vegetation and soil carbon pool losses on the Qinghai-Tibet Plateau, China
Effects of permafrost thawing on vegetation and soil carbon pool losses on the Qinghai-Tibet Plateau, China
复制标题
青藏高原多年冻土融化对植被和土壤碳库损失的影响
DOI：
10.1016/j.geoderma.2007.10.023
复制
发表时间：
2008-01-15
期刊：
影响因子：
6.1
通讯作者：
Wu Qingbo
中科院分区：
文献类型：
--
作者：
Wang Genxu;Li Yuanshou;Wu Qingbo
青藏高原多年冻土区高寒草地土壤有机碳含量为9.3-10.7 kg c/m2，比中国其它地区的草地土壤和热带萨凡纳草原土壤有机碳库含量高。易释放的轻组分有机碳（LFOC）占TOC的34-54%，特别是在表土（0-0.10英寸）中富集。高寒草甸和高寒草原土壤有机碳库中的LFOC随植被覆盖度的降低分别以指数和二次方的速率降低。当高寒草甸植被覆盖度从> 80 dm 2/m2降至60 dm 2/m2时，表层土壤TOC和LFOC分别下降20.4%和38.4%。高寒草甸植被覆盖度从50 dm 2/m2降低到30 dm 2/m2和< 15 dm 2/m2时，表层土壤LFOC含量分别下降60%和86.7%。在气候变暖的背景下，冻土和植被的退化导致了土壤有机碳库的严重流失。1986年至2000年期间发生的土地覆盖变化估计已导致1.8千兆克C（120毫克C/年）的SOC损失，并伴随着65%的LFOC减少，在0-0.30在青藏高原的多年冻土区的土壤层。由于该地区的生态系统对全球气候变化相当敏感，如果全球变暖持续下去，预计高寒草原生态系统将进一步退化。因此，全球气候变化对高寒草地土壤碳排放的影响应受到更多关注。(C)2007 Elsevier B. V.保留所有权利。
Bearing a total organic carbon (TOC) content of 9.3-10.7 kg c/m(2), alpine grassland soils of the Qinghai-Tibet plateau's permafrost region bear a greater organic carbon pool than do grassland soils in other regions of China or than tropical savannah soils. The easily released light fraction organic carbon (LFOC) accounts for 34-54% of the TOC and is particularly enriched in the topsoil (0-0.10 in). The LFOC in the organic carbon pool of alpine cold meadow and alpine cold steppe soils decreased at exponential and quadratic rates, respectively, as the vegetative cover decreased. When the vegetative cover of alpine cold meadows decreased from > 80 dm(2)/m(2) to 60 dm(2)/m(2), the topsoil TOC and LFOC dropped by 20.4% and 38.4%, respectively. Similarly, when the vegetative cover of alpine cold meadow decreased from 50 dm(2)/m(2) to 30 dm(2)/m(2) and < 15 dm(2)/m(2), the topsoil LFOC content dropped by 60% and 86.7%, respectively. Under climatic warming, the degradation of permafrost and vegetation have resulted in serious soil organic carbon (SOC) loss from the carbon pool. Land cover changes that occurred between 1986 and 2000 are estimated to have resulted in a 1.8 Gg C (120 Mg C/yr) loss in SOC, and a concomitant 65% decrease in the LFOC, in the 0-0.30 in soil layer in the Qinghai-Tibet plateau's permafrost regions. Since the region's ecosystems are quite sensitive to global climate changes, if global warming persists, alpine cold grassland ecosystems are expected to further degrade. Hence, the influence of global climatic change on soil carbon emissions from alpine grasslands should receive more attention. (C) 2007 Elsevier B.V. All rights reserved.