北方泥炭地不同发育阶段铁碳结合特征及其微生物驱动机制

Peatlands store one-third of global soil carbon, which is sensitive to climate change. The fluctuation of the peatlands make it be the hotspot of the iron, carbon and nitrogen biogeochemistry. Soil microbial communities couple iron and carbon biogeochemistry has been focused internationally, but the microbial regulation in the iron and iron bound organic should be focused during development of peatlands. So we will study the characteristics of the iron , iron oxidize and iron bound organic matter on different development stage through different temporal and spatial scales(depositional process, hydrogeography, regional hydrothermal pattern, etc.), and demonstrate iron bounding organic carbon accumulation by 14C ages of bulk soil organic matter and 2G model; Based on the method of enrichment cultivation and high-throughput sequencing, we will explore the distribution of iron-oxidizing /reducing bacteria and its succession characteristics. We will also explain the mechanisms that how iron-reducing bacteria affects soil organic carbon mineralization and how iron-oxidizing bacteria affects the organic carbon acumullation. Finally, the coupling mechanism and the connections among the development of peatlands, the iron variables, the microorganism and the organic carbon accumulation are studied by structural equation modeling, revealing that how microorganism affects iron and organic carbon accumulation during the development. The research, not only will enrich the basic theories of the development of peatlands and global change, but also will promote the development of the studies of peatlands and wetlands.

泥炭地是全球重要的碳库，对全球气候变化极为敏感；独特的氧化还原交替过程使其成为铁、碳、氮等元素生物地球化学循环热点研究区域。目前微生物驱动的铁碳耦合是国际研究热点，而泥炭地发育过程中铁及其结合碳如何变化，微生物驱动机制都是亟待解决的科学问题。因此本项目从沉积历史过程、水文地貌类型及区域水热格局等不同尺度，阐明不同发育阶段泥炭地铁赋存状态、铁氧化物类型及结合碳含量，利用14C定年及2G模型探究泥炭形成发育过程中铁对有机碳累积效应；通过富集培养及高通量测序手段，开展泥炭地铁微生物功能类群的时空分布特征及演变规律研究；揭示铁还原菌对有机碳矿化及铁氧化菌对铁碳结合的作用机制，利用结构方程模型探究泥炭地发育-铁形态-微生物-碳累积之间耦合机制及互馈过程，揭示泥炭发育过程中铁对有机碳累积的微生物驱动机制。本成果将进一步丰富泥炭地形成发育及全球变化研究的基础理论知识，促进泥炭地学及湿地学的发展。

泥炭地是全球重要的碳库，对全球气候变化极为敏感，独特的氧化还原交替过程使其成为铁、碳、氮等元素生物地球化学循环热点研究区域。目前微生物驱动的铁碳耦合是国际研究热点，而泥炭地发育过程中铁及其结合碳如何变化，微生物驱动机制都是亟待解决的科学问题。本课题以北方泥炭沼泽为研究对象，以湿地科学、环境科学和微生物生态学为基础，完成了不同发育阶段泥炭地土壤铁碳结合特征及其驱动因子解析。利用高通量测序方法解析泥炭地土壤铁氧化/还原菌时空分布及演变规律。同时，通过营养添加、增温和氧气控制实验阐明了微生物对有机碳吸附-分解的驱动机制。本课题对我国东北四个主要湿地分布区中典型的泥炭地进行多次野外考察，并收集泥炭地土壤、土壤水和植物样品等，总共获得土壤，水体，植物和微生物相关数据3500余个数据，依托基金支持并有基金标注发表的文章共23篇，其中20篇SCI，3篇CSCD。培养博士3名（已毕业2名），博士后3名。本课题研究结果将进一步丰富泥炭地形成发育及全球变化研究的基础理论知识，促进泥炭地学及湿地学的发展。