SREL Reprint #3796

Microbial community changes across time and space in a constructed wetland

Zeinah Elhaj Baddar1, Raven Bier1, Breann Spencer1, and Xiaoyu Xu1,2

1Savannah River Ecology Lab, University of Georgia, Aiken, South Carolina 29802, USA
2Warnell School of Forestry and Natural Resources, University of Georgia,
University of Georgia, Athens, Georgia 30605, USA

Abstract: Constructed wetlands are artificial ecosystems designed to replicate natural wetland processes. Microbial communities play a pivotal role in cycling essential elements, particularly sulfur, which is crucial for trace metal fixation and remobilization in these ecosystems. By their response to their environment, microbial communities act as biological indicators of the wetland performance. To address knowledge gaps pertinent to the changes in trace metal bioavailability in relation to microbial activities in the H-02 constructed wetland, we performed this study to investigate temporal and spatial variations in microbial communities by using molecular biology tools. Quantitative polymerase chain reaction and next generation sequencing techniques were employed to analyze archaeal and bacterial groups associated with sulfur and methane cycling. Alpha diversity indices were used to assess species richness, evenness, and dominance. Results indicated high gene abundance of Desulfuromonas (5.37 × 106 g.cell-1), methane oxidizing bacteria (6.92 × 106 g.cell-1), and methanogenic microorganisms (3.02 × 105 g.cell-1) during cool months. Warm months were marked by sulfate reducing bacteria dominance (3.31 × 106 g.cell-1), potentially due to competitive interactions and environmental conditions, higher temperatures, and lower redox potential. Spatial variability among microbial groups was insignificant, but trends in gene abundance indicated complex factors influencing these groups. Next generation sequencing data demonstrated Firmicutes as the most abundant phylum with over 50% regardless of the season or sampling location. Cool months exhibited higher alpha diversity than warm months. Overall, this study showed that seasonal changes significantly impacted the microbial communities in the H-02 constructed wetland that are associated with the sulfur cycle and eventually trace metal biogeochemistry, revealing two distinct mechanisms of the sulfur cycle between the two main seasons, whereas spatial variability effects were not conclusive.

Keywords: microbial community, constructed wetland, temporal variability, spatial variability, sulfur cycling

SREL Reprint #3796

Baddar, Z. E., R. Bier, B. Spencer, and X. Xu. 2024. Microbial community changes across time and space in a constructed wetland. ACS Environmental (4): 307-316.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).