LAII Flux Study: CO2 and Methane Fluxes by Ecosystem Type and Long-Term Feedback Relationships with the Atmosphere

本研究的主要目的是评估土壤有机质（SOM）的数量和质量，并测试在北极生态系统中的CO2和CH 4的生产中的作用，土壤有机质的活性组分。 该项目的第一阶段涉及对通量研究地点的土壤进行取样和全面定性，这些地点是由参与这一合作提案的所有专业人员共同选定的。 土壤特性鉴定将提供数据库，用于推断地理基础上的气体通量研究结果。 第二阶段涉及土壤和土壤溶液中的非活性和活性有机组分的分离和表征;然后在受控条件下使用呼吸实验鉴定微生物活性组分，并使用碳标记实验鉴定作为气体通量（CO2和CH 4）底物的活性组分。 据推测，CO2和CH 4的产生的主要来源是活性组分的SOM。 活性有机碳和非活性有机碳组分的组成、数量及其周转速率与北极不同生态系统的气体通量密切相关。 该项目是北极系统科学计划（ARCSS）更大的陆地/大气/冰相互作用（LAII）通量综合研究的一部分。

The major objective of this research is to assess the quantity and quality of soil organic matter (SOM) and to test the roles of the active fractions of SOM in CO2 and CH4 production in the arctic ecosystem. The first phase of this project involves the sampling and full characterization of soils on the flux study sites which were jointly selected by all PIs involved in this collaborative proposal. The soil characterization will provide database for extrapolating the results of gas flux studies over a geographic base. The second phase involves the isolation and characterization of the inactive and active organic fractions in soils and soil solutions; then identification of the microbial active fractions using respiration experiments under controlled conditions and the active components as substrates for gas flux (both CO2 and CH4) using carbon labelling experiments. It is hypothesized that the major sources of CO2 and CH4 production are the active fractions in SOM. The composition, quantity of active and inactive organic carbon fraction and their turnover rate are expected to closely relate to gas flux on different arctic ecosystems. This project is part of the larger integrated Land/Atmosphere/Ice Interactions (LAII) Flux study of the Arctic System Science (ARCSS) Program.