DISSERTATION RESEARCH: Photodegradation as an Abiotic Mechanism in the Decomposition of Surface Litter

分解是陆地生态系统中碳和营养物质再循环的主要过程，通常是由微生物进行的。光降解，即化合物在阳光下的化学分解，可能在很大程度上有助于暴露在地表的凋落物的分解，例如在草原或冻土带。然而，陆地生态系统中很少有研究量化光降解对总分解率的贡献，或研究光降解可能影响碳和氮循环的机制。这项工作将使用一系列的实验室实验，旨在分离光降解的直接和间接影响，并了解光降解如何与微生物活动相互作用以影响整体分解速率。该项目的结果可能会被整合到分解模型中，并将对理解光降解幅度随气候、大气成分和土地利用变化的变化具有重要意义。

Decomposition is a primary process by which carbon and nutrients are re-cycled in terrestrial ecosystems, generally by microbes. Photodegradation, the chemical breakdown of compounds by sunlight, may contribute substantially to decomposition of surface litter where it is exposed, such as in grasslands or tundra. However, few studies in terrestrial ecosystems have quantified the contribution of photodegradation to overall decomposition rates or have investigated the mechanisms by which photodegradation may affect the cycling of carbon and nitrogen. The proposed work will use a series of laboratory experiments aimed at separating direct and indirect effects of photodegradation and understanding how photodegradation may interact with microbial activity to affect overall decomposition rates. Results of this project may be integrated into models of decomposition and will have important implications for understanding changes in the magnitude of photodegradation in response to changes in climate, atmospheric composition, and land use.