Decline of soil respiration in northeastern Tibet through the transition into the Oligocene icehouse-猫眼课题宝

DOI：

10.1016/j.palaeo.2020.110016

发表时间：

2020-12

期刊：

Palaeogeography, Palaeoclimatology, Palaeoecology

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

A. Licht;G. Dupont‐Nivet;N. Meijer;J. Rugenstein;A. Schauer;J. Fiebig;A. Mulch;C. Hoorn;Natasha Barbolini;Zhaojie Guo

土壤呼吸(Rs)，即土壤中二氧化碳的产生，从沙漠到森林生态系统都急剧增加。因此，如果记录在沉积档案中，RsValue为识别过去的生态系统提供了一个潜在的工具。在这里，我们提出了一种从古土壤中重建过去Rs值的定量方法。这种方法逆转了土壤古生物量计，这是一种替代方法，可以从古土壤中估计过去的大气二氧化碳浓度值(CO2atm)，同时考虑Rs的小范围变化。我们利用来自海洋替代物的过去的CO2atm值，从西藏东北部长达2000万年的同位素记录中重建土壤呼吸，该记录涵盖了从始新世温室到渐新世冰库的过渡。我们发现，在过渡到渐新世冰库的过程中，RS至少下降了4倍，标志着中亚北部沙漠草原的扩张。结果表明，干旱加剧和季风降水减少，伴随着全球变冷，导致了土壤呼吸的下降。这些高度动态的研究表明，在使用土壤古生物量计重建CO2atm之前，需要对古土壤同位素数据进行系统的筛选

Soil respiration (Rs), the production of carbon dioxide in soils, increases dramatically from deserts to forested ecosystems. Rsvalues thus provide a potential tool to identify past ecosystems if recorded in sedimentary archives. Here, we propose a quantitative method to reconstruct past Rsvalues from paleosols. This method reverses the soil paleobarometer, a proxy that estimates past atmospheric CO2concentration values (CO2atm) from paleosols while considering a narrow range of variation for Rs. We use past CO2atmvalues from marine proxies to reconstruct soil respiration from a 20 million year-long isotopic record from northeastern Tibet covering the transition from the Eocene greenhouse to the Oligocene icehouse. We show that Rsdropped at least 4-fold through the transition into the Oligocene icehouse, marking the spread of boreal desert-steppes of Central Asia. We show that increasing aridity and the decline of monsoonal rainfall, in parallel with global cooling, caused the fall of soil respiration. These highly dynamic Rsemphasize the need for a systematic screening of paleosol isotopic data before using the soil paleobarometer to reconstruct CO2atm

Decline of soil respiration in northeastern Tibet through the transition into the Oligocene icehouse

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