Biotic Controls on Soil C Dynamics and N Cycling Under Elevated CO2

建议#：DEB-9708596研究员(S)：MILCHUNAS研究所：科罗拉多州立大学虽然在田间试验中广泛研究了大气二氧化碳浓度增加对初级生产力和其他地上生态系统过程的影响，但一般还没有进行地下二氧化碳影响的实验研究。本研究旨在探讨CO2浓度升高对科罗拉多草原土壤碳动态和氮素循环的影响。地下反应的主要驱动力被认为是CO2引起的植物C和N在可溶性分泌物与组织成分之间分配的变化，以及总C和N通量的变化。测量的重点是根分泌物、植物凋落物的化学成分和分解，以及土壤动物，特别是线虫的变化。结果将使用世纪模拟模型进行综合。这项研究是美国国家科学基金会环境地球化学和生物地球化学计划的一部分，得到了环境生物学、地球科学和大气科学部门的支持。

ABSTRACT PROPOSAL # : DEB-9708596 INVESTIGATOR(S) : MILCHUNAS INSTITUTION: COLORADO STATE UNIVERSITY Although the effects of increasing atmospheric CO2 concentrations on primary production and other aboveground ecosystem processes are widely studied in field experiments, experimental studies of the effects of CO2 belowground have generally not been done. The aims of this research are to investigate the effects of elevated CO2 concentrations on soil C dynamics and N cycling in Colorado grasslands. The main driver of belowground responses is assumed to be CO2-induced changes in plant C an N allocation among soluble exudates versus tissue components, in addition to changes in total C and N fluxes. The focus of the measurements is on root exudates, plant litter chemistry and litter decomposition, and changes in soil fauna, particularly nematodes. Results will be synthesized using the Century simulation model. This research is part of the NSF Environmental Geochemistry and Biogeochemistry Program, with support from the Divisions of Environmental Biology, Earth Sciences, and Atmospheric Sciences.