Sulfate and Dissolved Organic Carbon Concentrations Drive Distinct Microbial Community Patterns in Prairie Wetland Ponds

Prairie wetland ponds on the Great Plains of North America offer a diverse array of geochemical scenarios that can be informative about their impact on microbial communities. These ecosystems offer invaluable ecological services while experiencing significant stressors, primarily through drainage and climate change. In this first study systematically combining environmental conditions with microbial community composition to identify various niches in prairie wetland ponds, sediments had higher microbial abundance but lower phylogenetic diversity in ponds with lower concentrations of dissolved organic carbon ([DOC]; 10-18 mg/L) and sulfate ([SO₄ ^2-]; 37-58 mg/L) in water. As [DOC] and [SO₄ ^2-] increased, there was an initial decline in abundance but not phylogenetic diversity. Maximum values of both abundance and phylogenetic diversity occurred between 56 and 115 mg/L [DOC] and 5,000-6,000 mg/L [SO₄ ^2-] and decreased thereafter in ponds with 150-180 mg/L and 8,000-14,000 mg/L [DOC] and [SO₄ ^2-], respectively. These findings confirm that environmental variables shape the microbial communities and that key microbial taxa involved in sulfur and carbon cycling dominated these ponds potentially impacting vital biogeochemical processes such as bioavailability of heavy metals, carbon sequestration, and methane emissions.