地磁变化对趋磁微生物影响及其机理研究

认识地磁场对地质微生物的影响是地球环境演化与生命过程领域的前沿交叉课题。趋磁细菌是地质微生物与地磁场关系密切的类群，它们能利用细胞内合成纳米尺寸的、呈单（多）条链排列的磁铁矿或胶黄铁矿磁小体，感知地磁场并沿磁力线定向游弋；它们广泛参与自然界铁、碳、硫等元素循环，沉积物中化石磁小体还是沉积物磁和环境信号的重要载体。因此，趋磁细菌的生物地磁学研究对于地质微生物学、古地磁学和环境磁学都具有重要意义。项目选择环境中未培养的和实验室可培养的趋磁细菌作为研究对象，通过野外观测和实验模拟相结合，从行为学到分子机制，系统研究地磁环境及其变化对趋磁细菌的地理分布格局、细胞铁转运、磁小体合成和趋磁性等的影响，揭示趋磁细菌响应地磁场的机理。同时，实验研究磁小体记录沉积剩磁的能力，探讨沉积物中化石磁小体携带的古磁场与古环境信息。项目从地球物理学视角认识环境演化与生命过程，拓展生物地磁学交叉研究。

Earth is so far considered the sole planet in the Universe that harbors life. Earth’s magnetic field is essential to the origin and evolution of organisms, because the field protects life from harmful comic rays and solar winds, and serves as a free and global scale orientation cue for many of them, particularly, during their migrating or homing processes. The proposed project focuses on investigating effects of geomagnetic field on magnetotactic bacteria. Magnetotactic bacteria are a model group of microorganisms that can orient and swim along field lines of Earth’s magnetic field. They are world-wide in distribution and ubiquitous in sediments and water columns of freshwater, brackish, marine and hypersaline aquatic environments. However, diversity and distribution of magentotactic bacteria in nature remain poorly understood. In this project, comprehensive laboratory experiments, including room and low temperature rock magnetic measurements, molecular approaches, and transmission electron microscopy, redeposition experiments will be used to study the phylogenetic diversity, biogeographic distribution, and biomineralization of magnetotactic bacteria. Rock magnetic detection of magnetofossils in ancient lake sediments will be also carried out. Outcomes of this project will enable better understand the biodiversity and evolution of magnetotactic bacteria in nature, and the possible linkages between these microorganisms and the geomagnetic field.