CAREER: A Novel Approach to Understanding Microbial Metabolism and Soil Carbon Dynamics

土壤碳储量在很大程度上取决于植物生产力和有机质衰变之间的平衡。土壤微生物是有机物的主要分解者，它们的新陈代谢控制着从土壤中流失并以二氧化碳的形式返回大气的碳量。决定土壤碳命运的关键因素之一是土壤微生物将有机质转化为微生物生物量的效率。尽管微生物效率在确定土壤碳动态方面很重要，但人们对微生物效率如何响应环境变化知之甚少。在这个项目中，一种新的技术，热肺量测法将被用于原位测量暴露于长期增温和氮肥土壤中的微生物效率。全球变化正在改变陆地生态系统的功能。该项目将重点关注全球变化的两个方面，这两个方面对美国东北部具有特别重要的意义，即变暖和氮沉积。该项目将为气候变暖和氮肥如何相互作用影响土壤微生物代谢和碳损失提供证据，并将为全球碳和土壤有机质模型的输入提供有价值的数据。此外，将为新罕布什尔州制定一项为期五年的外展计划，向公众提供有关生态系统提供的服务（例如空气和水质）的可访问信息，以及全球变化如何影响生态系统维持这些服务的能力。这一目标将通过网站、当地国家公共广播电台的公共服务公告、公共交通系统的海报以及新罕布什尔项目学习树的生态系统服务模块来实现，这是一个全州范围的环境教育计划。

Soil carbon storage is determined to a large degree by the balance between plant productivity and organic matter decay. Soil microorganisms are the primary decomposers of organic matter and their metabolism controls how much carbon is lost from the soil and returned to the atmosphere as carbon dioxide. One of the key factors determining the fate of soil carbon is the efficiency with which soil microorganisms convert organic matter to microbial biomass. Despite its importance in determining soil carbon dynamics, little is known about how microbial efficiency responds to environmental change. In this project, a new technique, calorespirometry will be used to make in situ measurements of microbial efficiency in soils exposed to chronic warming and nitrogen fertilization.Global change is altering the functioning of terrestrial ecosystems. This project will focus on two aspects of global change that have particular significance for the northeastern U.S., warming and nitrogen deposition. This project will provide evidence for how warming and nitrogen fertilization interact to influence microbial metabolism and carbon loss from soils, and will provide valuable data for input into global carbon and soil organic matter models. Additionally, a five-year outreach program will be developed for the State of New Hampshire to provide accessible information to the general public on the services that ecosystems provide (e.g., air and water quality), and how global change is impacting the ability of ecosystems to maintain these services. This objective will be accomplished via a website, public service announcements on local National Public Radio stations, posters on public transport systems, and an ecosystems services module for New Hampshire Project Learning Tree, a statewide environmental education program.