Effects of Magnetic Minerals Exposure and Microbial Responses in Surface Sediment across the Bohai Sea

Extensive production and application of magnetic minerals introduces significant amounts of magnetic wastes into the environment. Exposure to magnetic minerals could affect microbial community composition and geographic distribution. Here, we report that magnetic susceptibility is involved in determining bacterial α-diversity and community composition in surface sediment across the Bohai Sea by high-throughput sequencing analysis of the 16S rRNA gene. The results showed that environmental factors (explained 9.80%) played a larger role than spatial variables (explained 6.72%) in conditioning the bacterial community composition. Exposure to a magnetite center may shape the geographical distribution of five dissimilatory iron reducing bacteria. The microbial iron reduction ability and electroactive activity in sediment close to a magnetite center are stronger than those far away. Our study provides a novel understanding for the response of DIRB and electroactive bacteria to magnetic minerals exposure.