中性微好氧亚铁氧化耦合二氧化碳同化是由特定微生物驱动的地球化学过程，是联结铁循环与重要生源要素循环的纽带。近年来已在淡水、湿地等环境发现了大量的微好氧亚铁氧化菌，稻田也是发生这一过程的理想场所。本申请以红壤区浅海沉积物、石灰岩、花岗岩和第四纪红粘土等母质发育的代表性稻田为对象，以微好氧亚铁氧化耦合二氧化碳同化为核心过程，建立凝胶梯度管培养体系，采用稳定同位素核酸探针技术结合分子生物学手段，首先，以代表性亚铁底物富集培养微好氧亚铁氧化细菌，阐明微好氧亚铁氧化耦合二氧化碳同化的底物效应与机制；其次，从化学和功能微生物群落两个方面阐明母质效应与机制；最后，重点阐明微生物在亚铁氧化耦合碳转化过程中的角色与功能，在功能群落、关键微生物、功能基因水平上阐明了上述耦合过程的分子生物学机制，为深入理解稻田铁/碳元素的生物地球化学循环及水稻土固碳培肥过程提供科学依据。

Neutrophilic, microaerophilic iron oxidation coupled with carbon dioxide assimilation is a biogeochemical process mediated by unique bacteria. It has great potential to couple iron and nutrient cycling at redox boundary. Substantial numbers of microaerophilic iron-oxidizing bacteria (FeOB) has been obtained from freshwater and wetland in recent years, and paddy soil is also an ideal environment for this process. Our proposed study will focus on microaerophilic iron oxidation coupled with carbon dioxide assimilation in representative paddy fields developed by different parent materials (e.g. shallow-sea sediment, limestone soil, granite soil, and quaternary red earth) in red soil. Here, we will establish gel-gradient tube cultures and combine 13C-DNA stable isotope probe with advanced molecular biological methods to: (1) elucidate the mechanisms and effects of ferrous substrates in microaerophilic iron oxidation coupled with carbon assimilation; (2) elucidate the chemical and microbial mechanisms and effects of parent materials in this process; (3) explore the microbial community structure, functional microorganisms and functional genes of iron oxidation and carbon assimilation. This work will elucidate the molecular mechanisms of microaerophilic iron oxidation coupled with carbon dioxide assimilation, enhance the understanding of biogeochemical cycling of Fe-C, and provide scientific knowledge for carbon fixation and sustained utilization of paddy soil.