Microbial community structure corresponds to nutrient gradients and human impact within coastal wetlands of the Great Lakes.

Microbial communities within the soil of Great Lakes coastal wetlands drive biogeochemical cycles, and provide other ecosystems services. However, there exists a lack of understanding of how microbial communities respond to nutrient gradients and human activity. This research sought to remedy this lack of understanding through exploration of microbial community diversity and microbial networks among coastal wetlands throughout the Great Lakes. Significant differences in microbial community structure were illuminated between Lake Erie and all other wetlands, and chemical and biological structure did not exist within Lake Erie with increasing soil depth. Beyond this, alpha diversity levels were highest within Lake Erie coastal wetlands. These diversity differences coincided with significantly higher nutrient levels within the Lake Erie region. Significant site-to-site variability existed within Lake Erie, East and North Saginaw Bay regions, suggesting site heterogeneity may impact microbial community structure. Several subnetworks of microbial communities and individual OTUs were related to chemical gradients among wetland regions, revealing several candidate indicator communities and taxa which may be useful for Great Lakes coastal wetland management. This research provides an initial characterization of microbial communities among Great Lakes coastal wetlands, and demonstrates that microbial communities could be negatively impacted by anthropogenic activities.