To understand the role of magnetotactic bacteria and how they contribute to the paleomagnetic and environmental signature of sediments

点击翻译按钮获取中文摘要

Most freshwater and marine environments host a broad spectrum of magnetotactic bacteria and other magnetic microorganisms that contain nano-sized iron minerals. These species are thought to play an important role in the iron cycle. Their contribution to the magnetic remanence of sediments is only now gaining appreciation in the paleomagnetic community, yet little is known how or why they use the Earth s magnetic field to place themselves in the particular ecological niche in which they exist. A high bacterial population density and broad diversity of magnetic microorganisms live in a pond within the confines of our paleomagnetic laboratory in Niederlippach, where the University of Munich (LMU) has agreed to establish the Niederlippach Center of Biomagnetism, with an initial investment of 227 k€ pending additional support from the DFG. Our goal is to use this pond as a natural laboratory to study magnetic bacteria, with particular focus on understanding their living habits and their role in governing how a magnetic remanence is acquired in sediments. To our knowledge, this Center, run together with the microbiology group of Dirk Schüler at LMU, will be the first of its kind in the world. Our proposed research concerns: (1) three-dimensional geochemical profiling (Eh, pH, S2~, etc.) of the pond, (2) magnetic characterization of the bacteria in the same profiles, (3) diagenetic processes leading to the acquisition of magnetization and subsequent changes in the magnetic signal, and (4) use of fossil magnetotactic bacteria as environmental proxies in the geological past.