Coupled Microbial and Geochemical Drivers of Methylmercury Variability in Prairie Wetlands (Dataset)

Yet, the heterogeneity of wetland environments complicates the identification of key regulators and controls on net MeHg concentrations. While high sulfate (SO₄^2-) and dissolved organic carbon (DOC) concentrations have been linked to high MeHg concentrations, the mechanisms underlying these relationships in prairie wetlands -whether causative or correlative- remain unclear.

Certain microorganisms are capable of Hg methylation using their <i>hgcA</i> and <i>hgcB</i> genes. In addition, biotic and abiotic demethylation processes are as important as methylation in determining net MeHg concentrations. In this study, we examined seven ponds with varying surface water SO₄^2- (37.02 to 14,333.65 mg/L) and DOC (9.8 to 168.8 mg/L) concentrations over the 2021 open water season in the Canadian Prairie Pothole Region, where MeHg concentrations ranged from 0.09 to 2.70 ng/L. DNA from sediment was analyzed using 16S metabarcoding and shotgun metagenomic sequencing, and water chemistry was assessed to characterize geochemical conditions.