Abstract
Originality-Significance Statement This research is original in providing an initial, geographically wide-ranging characterization of microbial communities of the Great Lakes coastal wetlands, an understudied system of wetlands directly bordering the North American Laurentian Great Lakes. Relationships between microbial communities within coastal wetland soils and geochemistry highlighted that anthropogenic impacts may be significantly influencing microbial community structure, as well as unique subnetworks of microbial taxa. Negative anthropogenic impacts to these coastal wetland communities could influence natural biogeochemical cycles which occur within coastal wetland soils, and by extension would directly influence the Great Lakes themselves.
Summary Microbial communities within the soil of Great Lakes coastal wetlands drive biogeochemical cycles and provide several other ecosystems services. However, there exists a lack of understanding of how microbial communities respond to nutrient gradients and human activity in these systems. This research sought to address this lack of understanding through exploration of microbial community diversity and 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 vary within Lake Erie with increasing soil depth. Beyond this, alpha diversity levels were highest within Lake Erie coastal wetlands. These diversity differences coincided with higher nutrient levels within the Lake Erie region. Site-to-site variability existed within Lake Erie, East and North Saginaw Bay regions, suggesting site-scale 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.