Temperature Driven Decoupling of Carbon Cycling in Freshwater Sediments and the Relative Production and Flux of Methane Versus Carbon Dioxide

甲烷是一种大气温室气体，是全球碳循环的组成部分。大部分甲烷是生物产生的，在全球范围内，每年转移到大气中的甲烷有20%-40%来自淡水湿地沉积物。然而，控制淡水湿地甲烷产生和释放的因素的关键方面仍然知之甚少。这项工作将在佛罗里达州、佐治亚州和马萨诸塞州的沉积物碳循环背景下研究甲烷动力学。研究人员将评估温度、有机碳有效性和微生物种群如何相互作用来调节复杂有机物的分解和甲烷的产生。温度是现代全球变化的一个重要方面。该研究计划强调野外采样和实验室实验，并围绕温度变化影响淡水沉积物中有机碳分解的速度和效率以及甲烷的产生这一工作假设进行组织。作为一种温室气体，甲烷在捕捉大气热量方面的效率是二氧化碳的二十多倍。因此，了解控制甲烷产生的因素对于理解和预测气候变化至关重要。该项目将促进我们对淡水生境中甲烷循环的理解，并将补充和扩大佛罗里达州、佐治亚州和马萨诸塞州正在进行的长期生态研究中的碳循环部分。它将跨学科领域课程与建模相结合，将涉及博士后、研究生和本科生，包括代表不足的少数群体的成员。

Methane is an atmospheric greenhouse gas that is an integral part of the global carbon cycle. Much of the methane is produced biologically, and globally, between 20-40% of the annual methane transfer to the atmosphere originates from freshwater wetland sediments. However, critical aspects of the factors regulating methane production and release from freshwater wetlands remain poorly understood. This work will examine methane dynamics within the context of the sediment carbon cycle at sites in Florida, Georgia and Massachusetts. The investigators will evaluate how temperature, an important aspect of modern global change, organic carbon availability and microbial populations interact to regulate breakdown of complex organic matter and production of methane. The research program emphasizes field sampling and laboratory experimentation and is organized around the working hypothesis that changes in temperature influence the rate and efficiency of organic carbon breakdown and the production of methane in freshwater sediments. As a greenhouse gas, methane is over twenty times as effective as carbon dioxide in trapping heat in the atmosphere. Thus, understanding the factors that control methane production is critical to understanding and predicting climate change. This project will advance our understanding of methane cycling in freshwater habitats, and will complement and expand the carbon cycling component of on-going long-term ecological research studies in Florida, Georgia and Massachusetts. It combines an interdisciplinary field program with modeling and will involve postdoctoral, graduate and undergraduate students, including members of underrepresented minority groups.