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

分解是一个基本的生态系统过程，通过这个过程，死亡有机物中的碳和营养物质被循环利用，但对这个过程的了解是不完整的，这一事实证明，目前的碳和营养物质循环的生物地球化学模型不能可靠地估计分解率。光降解，即有机物质在紫外线辐射下的光化学氧化，可能在决定草原系统等高度暴露地区的分解率方面发挥重要作用。该项目将解决目前对光降解对分解率的影响缺乏了解的问题。将利用一项多年期、多地点的实地分解实验和一系列实验室研究来衡量光降解对整个元素循环的直接和间接影响。这些结果将被整合到一个地球化学模型，可以更普遍地应用。本研究解决了复杂的分解过程中控制的生物和非生物因素。这些结果将使更好地估计碳和氮循环速率，以及提高预测循环速率在不同环境条件下如何变化的能力。该项目将通过三个LTER站点之间的合作以及为本科生，研究生和公众提供研究和教育机会的整合产生深远的影响。

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.