Photodegradation of Plant Litter in Grassland Ecosystems: A Mechanism for Uncoupling C and N Biogeochemistry

草原生态系统中植物凋落物的光降解：C 和 N 生物地球化学解偶联的机制

• 批准号: 0542935
• 负责人: Jennifer King
• 金额: --
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0542935&HistoricalAwards=false
• 关键词: Photodegradation; Plant; Litter; Grassland; Ecosystems

Decomposition is the basic ecosystem process by which carbon and nutrients in dead organic matter are recycled, yet knowledge of this process is incomplete, as evidenced by the fact that current biogeochemical models of carbon and nutrient cycling cannot reliably estimate rates of decomposition. Photodegradation, the photochemical oxidation of organic matter by ultraviolet radiation, may play an important role in determining rates of decomposition in highly exposed areas such as grassland systems. This project will address the current lack of understanding about the contribution of photodegradation to decomposition rates. A multi-year, multi-site field decomposition experiment and a series of laboratory studies will be used to measure the direct and indirect effects of photodegradation on overall element cycling. These results will be integrated into a biogeochemical model that can be applied more generally. This study addresses the complexity of decomposition as a process controlled by both biological and non-biological factors. The results will enable better estimates of carbon and nitrogen cycling rates as well as improved ability to predict how cycling rates may change under differing environmental conditions. The project will have far-reaching impact through collaboration between three LTER sites and integration of research and educational opportunities for undergraduates, graduate students, and the general public.

分解是基本的生态系统过程，死亡有机物中的碳和营养物质被循环利用，但对这一过程的了解尚不完整，目前的碳和营养循环生物地球化学模型不能可靠地估计分解速率。光降解，即有机物在紫外线照射下的光化学氧化，可能在确定高暴露区域（如草地系统）的分解速率方面发挥重要作用。该项目将解决目前对光降解对分解速率的贡献缺乏了解的问题。一项多年、多地点的现场分解实验和一系列实验室研究将用于测量光降解对整体元素循环的直接和间接影响。这些结果将被整合到一个可以更广泛应用的生物地球化学模型中。这项研究解决了复杂的分解作为一个过程控制的生物和非生物因素。研究结果将有助于更好地估计碳和氮的循环速率，并提高预测循环速率在不同环境条件下如何变化的能力。通过三个LTER站点之间的合作，以及对本科生、研究生和公众的研究和教育机会的整合，该项目将产生深远的影响。