羊草和大针茅群落土壤微生物对CO2浓度升高的响应及其对土壤碳库的反馈影响

项目名称： 羊草和大针茅群落土壤微生物对CO2浓度升高的响应及其对土壤碳库的反馈影响

项目编号： No.31200374

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 生态学

项目作者： 张琳

作者单位： 中国科学院植物研究所

项目金额： 24万元

中文摘要： 根系和凋落物是土壤有机碳的主要来源。CO2浓度升高改变了输入土壤有机质的量和质从而影响土壤碳库和碳循环，土壤微生物的响应和适应调控了碳库和碳循环响应和反馈。CO2浓度升高导致的草地生态系统有机碳输入改变对土壤碳库和碳循环的影响已有一些研究，但关注其对土壤微生物群落结构的影响及微生物对碳循环的反馈调控机制研究很少，限制了深入研究我国草地生态系统碳循环对全球气候变化的响应与适应机制。本项目以我国温带典型草原的羊草和大针茅群落为对象，研究高CO2浓度下有机质输入（量、质、途径）改变对土壤微生物群落结构和功能多样性的影响，区分和量化有机物输入改变对土壤碳库和碳循环的贡献，以及土壤微生物的响应与土壤有机碳库的关系。对揭示在全球变化背景下草地生态系统土壤碳库和碳循环的变化规律有重要科学意义，为预测未来全球气候变化对土壤碳贮存的影响提供科学依据。

中文关键词： CO2浓度增加；差异性响应；全球变化；草原；土壤微生物

英文摘要： As plant roots and aboveground litters are the main sources of the soil organic C, elevated CO2 has an impact on both the quality and quantity of fresh soil C inputs and potential to affect soil C sequestration and efflux. The decomposition and soil C release processes were regulated by the responses and feedbacks of soil microbe which lead to a positive or negative feedback to elevated CO2. Although many studies indicate that the increasing atmospheric CO2 may hold more C in the vegetation, few data are available about how changes in the composition of the soil microbial community affect decomposition rates and its feedbacks to elevated CO2 and eventually to soil C sequestration. The research aimed to understand soil C dynamics and feedbacks of changes in microbial traits to increased soil C inputs in temperate grassland. The study objectives were achieved by conducting a field experiment in which different qualities, quantities or sources of plant litters and root were added to the two different plant communities (Leymus chinensis and Stipa grandis communities) in temperate grassland, and the litter decomposition, soil microbial community composition, soil respiration and the component of soil C were measured to distinguish and quantify the contribution of soil carbon pool and carbon cycle, as well as the soil

英文关键词： co2 enrichment；different responses；global change；grassland；soil microorganism