O2 partitioning of sulfur oxidizing bacteria drives acidity and thiosulfate distributions in mining waters

• Published in: Nature communications Vol. 14; no. 1; pp. 2006 - 15
• Main Authors: Whaley-Martin, Kelly J., Chen, Lin-Xing, Nelson, Tara Colenbrander, Gordon, Jennifer, Kantor, Rose, Twible, Lauren E., Marshall, Stephanie, McGarry, Sam, Rossi, Laura, Bessette, Benoit, Baron, Christian, Apte, Simon, Banfield, Jillian F., Warren, Lesley A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10.04.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 38/22; 38/23; 38/90; 38/91; 631/208/191/2018; 631/326/171/1878; 704/172/169; 704/47/4112; Acidification; Acidity; Anoxic conditions; Bacteria; Genomics; Geochemistry; Humanities and Social Sciences; Impoundments; Leukocytes (neutrophilic); Metagenomics; Microorganisms; Mine tailings; Mine wastes; Mining; multidisciplinary; Oxidation; Science; Science (multidisciplinary); Speciation; Sulfur; Sulfur compounds; Sulfur oxidation; Tailings; Thiosulfate; Thiosulfates; Water quality
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-37426-8

The acidification of water in mining areas is a global environmental issue primarily catalyzed by sulfur-oxidizing bacteria (SOB). Little is known about microbial sulfur cycling in circumneutral pH mine tailing impoundment waters. Here we investigate biological sulfur oxidation over four years in a mine tailings impoundment water cap, integrating aqueous sulfur geochemistry, genome-resolved metagenomics and metatranscriptomics. The microbial community is consistently dominated by neutrophilic, chemolithoautotrophic SOB (relative abundances of ~76% in 2015, ~55% in 2016/2017 and ~60% in 2018). Results reveal two SOB strategies alternately dominate across the four years, influencing acid generation and sulfur speciation. Under oxic conditions, novel Halothiobacillus drive lower pH conditions (as low as 4.3) and lower [S 2 O 3 2− ] via the complete Sox pathway coupled to O 2 . Under anoxic conditions, Thiobacillus spp. dominate in activity, via the incomplete Sox and rDSR pathways coupled to NO 3 − , resulting in higher [S 2 O 3 2− ] and no net significant acidity generation. This study provides genomic evidence explaining acidity generation and thiosulfate accumulation patterns in a circumneutral mine tailing impoundment and has significant environmental applications in preventing the discharge of sulfur compounds that can impact downstream environments. These insights illuminate opportunities for in situ biotreatment of reduced sulfur compounds and prediction of acidification events using gene-based monitoring and in situ RNA detection. Microbial genomics is a widely under-utilized tool in mining in understanding water quality drivers. Here the authors show early acid generation and thiosulfate concentrations are driven by O2 dependent microbial sulfur oxidizing bacterial niches in a mine tailings impoundment