Microbial community structure and microbial networks correspond to nutrient gradients within coastal wetlands of the Laurentian Great Lakes.

Dean J Horton,Kevin R Theis,Deric R Learman,Donald G Uzarski

doi:10.1093/femsec/fiz033

Dean J Horton, Kevin R Theis + Show 2 more

Open Access

https://doi.org/10.1093/femsec/fiz033

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Abstract

ABSTRACTMicrobial communities within the soil of Laurentian Great Lakes coastal wetlands drive biogeochemical cycles and provide several other ecosystem 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 the lack of understanding through exploration of relationships among nutrient gradients, microbial community diversity, and microbial networks. Significant differences in microbial community structure were found among coastal wetlands within the western basin of Lake Erie and all other wetlands studied (three regions within Saginaw Bay and one region in the Beaver Archipelago). These diversity differences coincided with higher nutrient levels within the Lake Erie region. Site-to-site variability also existed within the majority of the regions studied, suggesting site-scale heterogeneity may impact microbial community structure. Several subnetworks of microbial communities and individual community members were related to chemical gradients among wetland regions, revealing several candidate indicator communities and taxa that 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.

Highlights

The Laurentian Great Lakes of North America are one of the largest freshwater systems on Earth, and are critical in supporting biogeochemical cycles, freshwater resources, biodiversity and economic viability of the surrounding region
Environmental data were analyzed with a Principal Component Analysis (PCA) and PC1 and PC2 explained 56.2% and 20.6% of the variation among samples, respectively (Fig. 2). perMANOVA found significant differences in physicochemical profiles based on region (R2 = 0.570, P ≤0.001) and depth (R2 = 0.058, P ≤ 0.01)
Lake Erie (LE) coastal wetlands were chemically distinct from other wetland regions (ESBT and northern Saginaw Bay (NSB); adjusted P = 0.01) according to perMANOVA and pairwise perMANOVA based on Euclidean distance

Summary

Introduction

The Laurentian Great Lakes of North America are one of the largest freshwater systems on Earth, and are critical in supporting biogeochemical cycles, freshwater resources, biodiversity and economic viability of the surrounding region. The Great Lakes region has been impacted by anthropogenic pressure, with cumulative stress having a particular impact on the western basin of Lake Erie (LE) (Danz et al 2007; Uzarski et al 2017). These negative impacts extend to ecological transition zones between upland and aquatic environments in the form of coastal wetlands that border the Great Lakes (Uzarski 2009). Negative anthropogenic impacts on microbial communities could influence the economic viability of the Great Lakes region, biodiversity retention and the functioning of critical elemental cycles, which commonly occur within freshwater wetlands

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