DISSERTATION RESEARCH:Will CO2-mediated Increases in Fine-root Litter Progressively Decrease Forest N Availability by Increasing N Immobilization in Soil Organic Matter?

土壤具有长期储存碳的能力。 植物残骸在土壤剖面中免受分解的程度将决定土壤中储存的碳和氮的量，以响应大气中二氧化碳浓度的上升。 本研究的目的是将细根凋落物的分解与土壤有机质中碳和氮的固定联系起来。 具有贫化碳 13 同位素特征的细根和土壤有机质将从落叶林中的 CO2 富集实验中获取，并在相互移植实验中分解。分解的细根中的碳将被量化，因为它被转移到具有不同寿命的土壤有机质部分。该项目的结果将增进对调节森林生态系统地上和地下碳储存的陆地过程的理解，并为用于预测生态系统对气候变化反应的模型提供信息。

Soils have the capacity to store carbon for a long time. The degree to which plant remains are protected from decomposition in the soil profile will determine the amount of carbon and nitrogen stored in soils in response to rising atmospheric concentrations of carbon dioxide. The objective of this research is to mechanistically link the decomposition of fine-root litter to carbon and nitrogen immobilization in soil organic matter. Fine roots and soil organic matter with a depleted carbon-13 isotope signature will be taken from a CO2-enrichment experiment in a deciduous forest stand and decomposed in a reciprocal transplant experiment. Carbon from the decomposing fine roots will be quantified as it is transferred to fractions of soil organic matter with different longevities. Results of this project will advance the understanding of terrestrial processes that regulate above- and belowground carbon storage in forested ecosystems, and inform models used to predict ecosystem responses to climatic change.