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

分解是死有机物中碳和养分循环的基本生态系统过程，但对这一过程的认识并不完整，现有的碳和养分循环生物地球化学模型不能可靠地估计分解速度。光降解，即有机物在紫外线辐射下的光化学氧化，可能在确定草原系统等高暴露地区的分解速度方面发挥重要作用。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。将利用多年、多地点的野外分解实验和一系列实验室研究来衡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普遍应用的生物地球化学模型中。这项研究探讨了分解的复杂性，它是一个由生物和非生物因素控制的过程。这一结果将使人们能够更好地估计碳和氮的循环速率，并提高预测不同环境条件下循环速率可能发生变化的能力。该项目将通过三个LTER站点之间的合作以及为本科生、研究生和普通公众整合研究和教育机会而产生深远的影响。

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.