Belowground C Sources and Sinks in Arctic Tundra Ecosystems

摘要OPP 9615942纳德尔霍夫海洋生物实验室该项目旨在研究气候和环境对地下碳源输入冻土的控制以及冻土中碳平衡的影响。该项目的具体目标包括：1)量化湿莎草冻土带的根部生产和根源碳固定；2)评估全球变化如何影响从地下来源到土壤的碳输入速率和这些碳输入在北极生态系统中的去向；3)描述当前和预计气候条件下土壤-水-大气界面上根源碳通量的特征。这里提出的碳标记实验将允许测量植物对地下生产的碳分配、细根周转、从植物到土壤和大气池的碳转移速率，以及从几天到几年的时间尺度上的土壤碳周转速率。如果不对地下碳动态进行这样的研究，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.