Dissertation Research: Does The Impact of Climate Change On Rates of Soil N Processing Result in Part From Changes in Microbial community composition?

论文研究：气候变化对土壤N处理速率的影响是否部分源于微生物群落组成的变化？加州大学伯克利分校的达蒙·布拉德伯里和玛丽·费尔斯通预测，全球变化将改变大陆的温度和降水模式，进而影响土壤微生物活动。本文主要研究模拟气候变化对土壤微生物群落组成和土壤氮循环的影响。微生物催化土壤中氮的主要转化，包括树叶、木材和其他有机物的分解。在分解过程中，氮等必需营养物质以植物可利用的无机形式释放出来。由于氮在温带系统中可能是植物的限制性养分，因此了解控制土壤中氮有效性的微生物过程对于了解森林中植物生产力和碳保持非常重要。微生物对氮的利用也产生一氧化二氮，一种温室气体和平流层臭氧消耗的媒介。了解氮循环速率与土壤微生物群落组成和生理响应特征之间的关系，将有助于更好地预测陆地生态系统对全球环境变化的响应，并在理解陆地生态系统功能的微生物基础方面取得重大进展。博士论文改进基金将允许加州大学伯克利分校的博士候选人Damon Bradbury使用新型DNA微阵列技术分析红木林土壤中的细菌群落，并进行化学分析，以表征由于湿度和温度变化而发生的N循环动态变化的群落生理控制。

DEB-0508953 Dissertation Research: Does the impact of climate change on rates of soil N processing result in part from changes in microbial community composition?Damon Bradbury and Mary Firestone, University of California, Berkeley Global change is predicted to alter continental patterns of temperature and precipitation which will in turn impact soil microbial activity. This dissertation research project examines the impact of simulated climate change on microbial community composition and soil nitrogen (N) cycling. Microorganisms catalyze the major transformations of N in soils including the decomposition of leaves, wood and other organic matter. During decomposition processes, essential nutrients such as N are released as inorganic forms that are available to plants. Since N can be a limiting nutrient to plants in temperate systems, an understanding of the microbial processes that control availability of N in soils is important for understanding plant productivity and carbon retention in forests. Microbial N utilization also produces nitrous oxide, a greenhouse gas and a mediator of stratospheric ozone depletion. Understanding the relationship between the rates of N-cycling and the composition and physiological response characteristics of soil microbial communities will allow improved prediction of terrestrial ecosystem response to global environmental change as well as constituting a significant advancement in understanding the microbial basis of terrestrial ecosystem function. Doctoral Dissertation Improvement Grant funds will allow Damon Bradbury, a PhD candidate at University California at Berkeley, to use novel DNA microarray technology to analyze bacterial communities in Redwood Forest soils and perform chemical analyses to characterize the community physiological control over changes in N cycling dynamics that occur due to changes in moisture and temperature.