Dissertation Research: Global Warming and Soil Organic Matter Dynamics: An Experimental Investigation of the Effects of Climate on Soil Carbon Pool Structure

9623433哈特全球变暖和土壤有机质动态：气候对土壤碳库结构影响的实验研究。在高海拔草甸生态系统中进行的变暖操作的结果表明，变暖可能会减少大量土壤有机质中的碳储量。由于这种影响将构成一个积极的反馈机制，全球变暖预测从目前的温室气体排放量，理解这是重要的，以充分了解全球变暖本身的资金要求本提案将提供进一步调查的土壤碳库的结构在研究生态系统。其目的是更好地量化土壤碳损失的幅度，确定土壤碳的来源，并了解潜在的动态，这将决定它可能运行的时间尺度。 具体而言，PI建议应用：1）土壤有机质分级技术的最新进展，2）正在开发的新方法来量化微生物分解群落的结构，从升温操作的土壤。有机质分馏根据周转时间将土壤碳分成库（从而揭示预测对变暖的长期反应所必需的结构）;确定微生物分解者群落中可能与土壤碳结构变化相关的任何潜在变化将有助于阐明生态系统对变暖反应的重要生物机制。

9623433 Harte Global warming and soil organic matter dynamics: an experimental investigation of the effects of climate on soil carbon pool structure. Results from an ongoing warming manipulation in a high-altitude meadow ecosystem indicate that warming may be reducing the stock of carbon in the bulk soil organic matter. Since such an effect would constitute a positive feedback mechanism to the global warming predicted to follow from current greenhouse gas emissions, understanding it is important to fully understanding global warming itself The funds requested by this proposal will provide for a further investigation of the structure of the soil carbon pool in the study ecosystem. The aim is to better quantify the magnitude of the soil carbon loss, identify the pools of soil carbon from which it comes, and understand the underlying dynamics that will determine the timescale over which it might operate. Specifically, the PIs propose to apply: 1) recent advances in soil organic matter fractionation techniques, and 2) new methods being developed to quantify the structure of microbial decomposer communities, to soils from the warming manipulation. Organic matter fractionation divides soil carbon into pools according to turnover time (thereby revealing structure essential to predicting the long-term response to warming); identifying any potential shifts in the microbial decomposer community that might be associated with changes in the soil carbon structure will help illuminate biological mechanisms important in ecosystem response to warming.