Speleothem biomarker evidence for a negative terrestrial feedback on climate during Holocene warm periods
Speleothem biomarker evidence for a negative terrestrial feedback on climate during Holocene warm periods
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全新世温暖时期陆地对气候负反馈的洞穴生物标志物证据
DOI：
10.1016/j.epsl.2019.115754
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发表时间：
2019
影响因子：
5.3
通讯作者：
Shucheng Xie
中科院分区：
文献类型：
--
作者：
Canfa Wang;James A.Bendle;Sarah E.Greene;Michael L.Griffiths;Junhua Huang;Heiko Moossen;Hongbin Zhang;Kate Ashley;Shucheng Xie
了解陆地碳储存如何反馈温暖的气候状态对于改善全球变暖预测至关重要。如果变暖增加土壤碳分解率，土壤可能对气候起到积极的反馈作用。相反，如果净初级生产力（NPP）的增加超过分解的增加，气候反馈将是负面的。在这里，我们利用第一个古气候应用的化合物特定的δ 13 C测量的n-脂肪酸生物标志物（从中国中部的石笋提取），以限制流域陆地碳循环反馈的响应在全新世温暖的阶段。我们解决在这些温暖/湿润的间隔在集水区的C3植物的比例增加。此外，我们推断，异养土壤呼吸是高度基板选择性，表明NPP超过分解和集水区表现为碳汇（介导和增强的相对比例的变化C3与C4植物）。因此，我们提供的古气候证据表明，亚热带土壤在温暖/潮湿的气候作为有机碳的汇，从而作为一个负的气候反馈，在温暖的气候阶段。
Understanding how terrestrial carbon storage feeds back on warm climate states is critical for improving global warming projections. Soils may act as a positive feedback on climate if warming increases soil carbon decomposition rates. Conversely, if increases in net primary production (NPP) exceed increases in decomposition, the climate feedback will be negative. Here we utilize the first palaeoclimatic application of compound-specific δ 13 C measurements on n-fatty acid biomarkers (extracted from a stalagmite from central China) to constrain the response of catchment terrestrial carbon cycle feedbacks during warmer phases of the Holocene. We resolve proportional increases in C 3 plants in the catchment area during these warmer/wetter intervals. Moreover, we infer that heterotrophic soil respiration was highly substrate selective, indicating that NPP outpaced decomposition and the catchment behaved as a carbon sink (mediated and enhanced by changes in the relative proportion of C 3 vs. C 4 plants). Thus, we provide palaeoclimate evidence that subtropical soils in a warmer/wetter climate acted as a sink for organic carbon, and thus as a negative climate feedback, during warmer climatic phases.