DISSERTATION RESEARCH: Altered Rainfall Impacts on Carbon and Nitrogen Cycling in California Grassland

土壤中的碳储量超过了活植物、大气或化石燃料排放中的碳。 这项研究测试了未来气候变化，降雨量增加，对土壤碳质量的影响，在加州一年生草原。 在这个生态系统中，降雨量增加的一个可能结果是土壤微生物呼吸作用增加（土壤微生物将土壤碳转化为二氧化碳），留下的碳更难降解。 在实验室和现场应用的两种技术将跟踪这一过程。 首先，土壤碳将被分级：根据密度分为轻组分或重组分。 其次，放射性碳分析将用于确定每一部分的周转率（土壤碳转化为二氧化碳的速度）。 这些技术可以检测土壤碳质量的变化，即使没有变化，在总土壤碳量。 这项研究将加强我们对降雨对碳循环和预算的影响的理解。

The soil carbon reservoir outweighs the carbon in living plants, the atmosphere, or fossil fuel emissions. This study tests the effects of a future climate change, increased rainfall, on soil carbon quality in a California annual grassland. One possible outcome of increased rainfall in this ecosystem is increased soil microbial respiration (conversion of soil carbon to carbon dioxide by soil microorganisms), leaving behind carbon more resistant to degradation. Two techniques, applied in the laboratory and the field, will track this process. First, soil carbon will be fractionated: separated into light or heavy fractions based on density. Second, radiocarbon analysis will be used to determine a turnover rate (how fast soil carbon is converted to carbon dioxide) for each fraction. These techniques may detect changes in soil carbon quality even if no changes are seen in total soil carbon quantity. This study will enhance our understanding of rainfall effects on carbon cycling and budgets.