Magnetotactic bacteria (MTB), which can mineralize nano-sized magnetite or greigite crystals within cells, play important roles in biogeochemical processes, e.g., iron and sulfur cycling, and depositional remanent magnetization acquisitions. Despite decades of research, the knowledge of MTB distribution and ecology is still limited. In the present study, Dr. Lin Wei and his supervisor Prof. Pan Yongxin from IGG investigated temporal variation of MTB communities in freshwater sediment microcosms based on 16S rRNA genes and UniFrac analyses. Two microcosms (MY8 and MY11) collected from two separate sites in Lake Miyun (Beijing, China) were analyzed. Over a three-month period, temporal variation of MTB communities was evident in both microcosms. In addition, the phylogenetic discrepancy of MTB communities between two microcosms is more prominent than that of the same microcosm at different times, implying adaptation of MTB phylogenetic lineages to specific microenvironments. Among measured physical-chemical parameters, a strong correlation was shown between nitrate and the main genetic variability of MTB communities, indicating that nitrate mayinfluence the occurrence of MTB phylogenetic lineages in natural environments.

These results suggest that MTB represent particularly good models for studying community dynamics and biogeography, since in contrast to most other uncultivated bacteria they can be easily detected and selectively collected from environmental samples to near homogeneity by means of their magnetically directed motility.

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