Belowground C Sources and Sinks in Arctic Tundra Ecosystems

摘要 N9615942 Nadelhoffer海洋生物实验室 该项目的目的是描述气候和环境控制的碳输入苔原土壤从地下来源和苔原土壤中的碳平衡。 该项目的具体目标包括：1）量化湿莎草苔原的根生产和根源固碳，2）评估全球变化如何影响地下来源的碳输入到土壤的速率以及这些碳输入在北极生态系统中的命运，以及3）表征当前和预测气候条件下土壤-水-大气界面的根源碳通量。 这里提出的碳标记实验将允许测量植物碳分配到地下生产，细根周转率，从植物到土壤和大气池的碳转移率，以及土壤碳周转率在几天到几年的时间尺度。 如果不对地下碳动力学进行研究，就很难对北极生态系统对气候和环境变化的反应做出现实的预测。

ABSTRACT OPP 9615942 NADELHOFFER MARINE BIOLOGICAL LABORATORY This project is designed to characterize climatic and environmental controls on carbon inputs to tundra soils from belowground sources and on carbon balances in tundra soils. Specific objectives of this project include 1) quantifying root production and root-derived carbon fixation in wet sedge tundra, 2) assessing how global change influences both rates of carbon inputs from belowground sources to soils and the fate of these carbon inputs in arctic ecosystems, and 3) characterizing the fluxes of root-derived carbon across the soil-water-atmosphere interface under current and projected climatic conditions. The carbon-labeled experiments proposed here will permit measurements of plant carbon allocation to belowground production, fine root turnover, rates of carbon transfer from plants to soil and atmospheric pools, and rates of soil carbon turnover over timescales of days to years. Without such research on belowground carbon dynamics, it will be difficult to develop realistic predictions of arctic ecosystem responses to climate and environmental change.