Accelerated microbial turnover but constant growth efficiency with warming in soil
Accelerated microbial turnover but constant growth efficiency with warming in soil
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DOI：
10.1038/nclimate2361
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发表时间：
2014-10-01
影响因子：
30.7
通讯作者：
Dijkstra, Paul
中科院分区：
文献类型：
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作者：
Hagerty, Shannon B.;van Groenigen, Kees Jan;Dijkstra, Paul
预计气温上升将减少全球土壤碳（C）储量，推动对气候变化的积极反馈（1-3）。然而，这一预测的机制尚未得到很好的理解，包括温度如何影响微生物酶动力学，生长效率（MGE）和营业额（4，5）。在这里，在一个实验室研究中，我们表明，微生物营业额加速变暖，沿着酶动力学，确定微生物呼吸温度变化的反应。相比之下，MGE通常被认为会随着变暖而下降（6-8），没有显示出温度敏感性。微生物-酶模型表明，这种温度敏感的微生物营业额将促进土壤C积累与变暖，在传统的土壤地球化学模型预测的减少土壤C相反。此外，增加微生物周转的影响不同于减少MGE的影响，导致土壤碳储量的较大增加。我们的研究结果表明，土壤碳变暖的反应是受微生物周转的变化。这种控制应包括在下一代模型，以提高预测土壤碳反馈变暖。
Rising temperatures are expected to reduce global soil carbon (C) stocks, driving a positive feedback to climate change(1-3). However, the mechanisms underlying this prediction are not well understood, including how temperature affects microbial enzyme kinetics, growth efficiency (MGE), and turnover(4,5). Here, in a laboratory study, we show that microbial turnover accelerates with warming and, along with enzyme kinetics, determines the response of microbial respiration to temperature change. In contrast, MGE, which is generally thought to decline with warming(6-8), showed no temperature sensitivity. A microbial-enzyme model suggests that such temperature sensitive microbial turnover would promote soil C accumulation with warming, in contrast to reduced soil C predicted by traditional biogeochemical models. Furthermore, the effect of increased microbial turnover differs from the effects of reduced MGE, causing larger increases in soil C stocks. Our results demonstrate that the response of soil C to warming is affected by changes in microbial turnover. This control should be included in the next generation of models to improve prediction of soil C feedbacks to warming.