Temperature-associated increases in the global soil respiration record
Temperature-associated increases in the global soil respiration record
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DOI：
10.1038/nature08930
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发表时间：
2010-03-25
期刊：
影响因子：
64.8
通讯作者：
Thomson, Allison
中科院分区：
文献类型：
--
作者：
Bond-Lamberty, Ben;Thomson, Allison
土壤呼吸（R-S）是微生物和植物呼吸的二氧化碳（CO2）从土壤表面到大气的通量，是第二大陆地碳通量（1-3）。然而，人们对R-S的动力学还没有很好地了解，全球通量仍然没有得到很好的约束（4,5）。生态系统变暖实验（6,7）、模型分析（8,9）和基础生物动力学（10）都表明，R-S应该随着气候变化而变化。由于R-S的空间变异性大，土壤介质难以接近，遥感仪器无法在大尺度上测量R-S，因此很难在观测上证实这一点。尽管存在这些限制，但仍有可能在现有的40年R-S室测量记录中辨别气候驱动的区域或全球R-S值变化。本文构建了一个与高分辨率历史气候数据相匹配的全球R-S观测数据库，在考虑了年平均气候、叶面积、氮沉降和CO2测量技术变化等因素后，发现了一个以前未知的R-S记录的时间趋势。气温异常（与1961-1990年平均值的偏差）与R-S变化呈显著正相关。我们估计2008年全球R-S（即2008年地球陆地表面的通量）为98 +/- 12 Pg C，并且在1989年至2008年期间增加了0.1 Pg C /年（-1），这意味着全球R-S对气温（Q(10)）的响应为1.5。全球R-S值的增加并不一定构成对大气的正反馈，因为它可能是由更高的土壤碳输入驱动的，而不是由储存的旧碳的动员驱动的。然而，现有的数据与响应全球气候变化的陆地碳循环加速是一致的。
Soil respiration, R-S, the flux of microbially and plant-respired carbon dioxide (CO2) from the soil surface to the atmosphere, is the second-largest terrestrial carbon flux(1-3). However, the dynamics of R-S are not well understood and the global flux remains poorly constrained(4,5). Ecosystem warming experiments(6,7), modelling analyses(8,9) and fundamental biokinetics(10) all suggest that R-S should change with climate. This has been difficult to confirm observationally because of the high spatial variability of R-S, inaccessibility of the soil medium and the inability of remote-sensing instruments to measure R-S on large scales. Despite these constraints, it may be possible to discern climate-driven changes in regional or global R-S values in the extant four-decade record of R-S chamber measurements. Here we construct a database of worldwide R-S observations matched with high-resolution historical climate data and find a previously unknown temporal trend in the R-S record after accounting for mean annual climate, leaf area, nitrogen deposition and changes in CO2 measurement technique. We find that the air temperature anomaly (the deviation from the 1961-1990 mean) is significantly and positively correlated with changes in R-S. We estimate that the global R-S in 2008 (that is, the flux integrated over the Earth's land surface over 2008) was 98 +/- 12 Pg C and that it increased by 0.1 Pg C yr(-1) between 1989 and 2008, implying a global R-S response to air temperature (Q(10)) of 1.5. An increasing global R-S value does not necessarily constitute a positive feedback to the atmosphere, as it could be driven by higher carbon inputs to soil rather than by mobilization of stored older carbon. The available data are, however, consistent with an acceleration of the terrestrial carbon cycle in response to global climate change.