Does Microbial Ecophysiological Response to Long-Term Environmental Change Control Ecosystem Carbon Storage?

该提案旨在增加我们对土壤生物在不断变化的环境条件下碳循环中所起作用的理解。我们对生态系统功能理解的最大差距之一在于我们对土壤群落如何受到环境变化的影响以及这些影响如何反馈改变植物群落动态的理解。很少有研究明确调查了多种全球变化驱动因素对微生物群落的影响及其对碳动力学的控制。在这项研究中，我们建议量化的长期响应的微生物群落的一套全球变化的驱动程序，并测试一个概念模型，预测土壤中的碳流量和命运下的CO2浓度升高的碧玉岭全球变化实验（JRGCE）设施。我们将使用微生物脂质的化合物特异性13 C同位素特征直接将碳利用和土壤群落组成联系起来，并将评估微生物功能潜力的长期变化。通过增加我们对土壤生物成分的了解，这项工作的结果将提高我们预测生态系统对全球范围人为变化的反应的能力。特别是，它将增加我们对控制土壤碳固存的因素的理解。此外，这一项目对于在研究全球范围的变化对陆地生态系统的影响的研究小组之间建立综合和协同作用将是重要的。这种类型的跨学科的相互作用在人类全球变化的研究中变得越来越重要。

This proposal is designed to increase our understanding of the role played by soil organisms in carbon cycling under changing environmental conditions. One of the largest gaps in our understanding of ecosystem functioning lies in our understanding of how soil communities are impacted by environmental changes, and how these impacts feedback to alter plant community dynamics. Few studies have explicitly investigated the impact of multiple global change drivers on microbial communities and their control over carbon dynamics. In this study, we propose to quantify the long-term response of the microbial community to a suite of global change drivers, and test a conceptual model predicting carbon flow and fate in soil under elevated CO2 at the Jasper Ridge Global Change Experiment (JRGCE) facility. We will directly link carbon utilization and soil community composition using compound-specific 13C isotope signatures of microbial lipids, and will assess long-term changes in microbial functional potential. By increasing our understanding of the soil biological component, the results of this work will enhance our ability to predict ecosystem response to global-scale anthropogenic changes. In particular, it will increase our understanding of what controls soil carbon sequestration. Further, this project will be important in creating synthesis and synergy among research groups studying the effects of global-scale changes on terrestrial ecosystems. This type of interdisciplinary interaction is becoming increasingly important in studies of anthropogenic global changes.