Wildlife Institute of India, Dehradun, Uttarakhand, 248001, India.
Sci Rep. 2021 Nov 29;11(1):23038. doi: 10.1038/s41598-021-02199-x.
Soil respiration (SR), a natural phenomenon, emits ten times more CO from land than anthropogenic sources. It is predicted that climate warming would increase SR in most ecosystems and give rise to positive feedback. However, there are uncertainties associated with this prediction primarily due to variability in the relationship of SR with its two significant drivers, soil temperature and moisture. Accounting for the variabilities, we use a climosequence in Himalaya with a temperature gradient of ~ 2.1 °C to understand the variations in the response of SR and its temperature sensitivity to climate change. Results indicate an equilibrium in SR ranging from 1.92 to 2.42 µmol m s across an elevation gradient (3300-3900 m) despite its increased sensitivity to temperature (Q) from 0.47 to 4.97. Additionally, moisture reduction towards lower elevation weakens the temperature-SR relationship. Finally, soil organic carbon shows similarities at all the elevations, indicating a net-zero CO flux across the climosequence. The findings suggest that as the climate warms in this region, the temperature sensitivity of SR reduces drastically due to moisture reduction, limiting any change in SR and soil organic carbon to rising temperature. We introduce an equilibrium mechanism in this study which indicates the resilient nature of SR to climate change and will aid in enhancing the accuracy of climate change impact projections.
土壤呼吸(SR)是一种自然现象,其释放的 CO 量是人为源的十倍。据预测,气候变暖将增加大多数生态系统中的 SR,并引发正反馈。然而,由于 SR 与其两个重要驱动因素(土壤温度和湿度)之间关系的可变性,该预测存在不确定性。为了考虑到这些可变性,我们利用喜马拉雅山的气候序列,该序列具有约 2.1°C 的温度梯度,以了解 SR 及其对气候变化的温度敏感性的变化。结果表明,尽管 SR 对温度(Q)的敏感性从 0.47 增加到 4.97,但在海拔梯度(3300-3900 米)上,SR 的平衡范围为 1.92 至 2.42 µmol m s。此外,较低海拔处的水分减少削弱了温度-SR 关系。最后,土壤有机碳在所有海拔高度上都具有相似性,表明在整个气候序列中 CO 通量为净零。研究结果表明,随着该地区气候变暖,由于水分减少,SR 的温度敏感性会急剧降低,从而限制了 SR 和土壤有机碳对气温升高的任何变化。我们在本研究中引入了一种平衡机制,该机制表明 SR 对气候变化具有弹性,这将有助于提高气候变化影响预测的准确性。