Sulfur-based denitrification offers unique advantages in nitrogen removal in low-carbon environments. Despite its importance, the prevalence, controlling factors, and microbial mediators of sulfur-based denitrification in aquifers remain largely unknown. By integrating multiple stable isotopes and genome-resolved metagenomics, we investigated the coupling of nitrogen and sulfur cycling along the groundwater flowpath from unconfined to confined alluvial-lacustrine aquifers in the Poyang Lake Plain, China. Isotope (i.e., δ15N-NO3-, δ18O-NO3-, δ34S-SO42-, δ18O-SO42-, δ18O-H2O, δ13C-DIC, and δ13C-DOC) fractionation and hydrogeochemical trends indicated a transition from nitrification-dominated processes in the unconfined aquifer to denitrification, sulfide oxidation, and sulfate reduction in the confined aquifer. A significant negative correlation between δ34S-SO42- and δ15N-NO3-, along with a significant positive correlation between genes involved in sulfide oxidation and nitrate reduction, suggested cryptic coupling between sulfide oxidation and nitrate reduction. Sulfur-autotrophic denitrifying metagenome assembly genomes encoding Calvin-Benson-Bassham carbon fixation and rTCA pathways, such as Burkholderiales, Rhodocyclaceae, and Sulfurimonas, were enriched in the confined aquifer and co-occurred with sulfate reducers (Pseudomonadota and Desulfobacterota). These results highlighted sulfur cycling consortia when sulfate was reduced to facilitate removal of nitrate via sulfur-based denitrification. These findings reveal the role of cryptic sulfur cycling in sustaining denitrification in aquifers, offering new insights into nitrogen-sulfur interactions in subsurface ecosystems.
Deciphering Sulfur-Based Denitrification in Confined Alluvial-Lacustrine Aquifers through Multi-isotope (15N, 34S, 13C, and 18O) and Metagenomic Analyses.
Xianglong Chen,Yizhi Sheng,Guangcai Wang,Fu Liao,Pengpeng Zhou
Published 2025 in Environmental Science and Technology
ABSTRACT
PUBLICATION RECORD
- Publication year
2025
- Venue
Environmental Science and Technology
- Publication date
2025-12-29
- Fields of study
Medicine, Environmental Science
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
- No claims are published for this paper.
CONCEPTS
- No concepts are published for this paper.
REFERENCES
CITED BY
- No citing papers are available for this paper.
Showing 0-0 of 0 citing papers · Page 1 of 1