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Research article - Peer-reviewed, 2023

Microbial communities mediating net methylmercury formation along a trophic gradient in a peatland chronosequence

Wang, Baolin; Hu, Haiyan; Bishop, Kevin; Buck, Moritz; Bjorn, Erik; Skyllberg, Ulf; Nilsson, Mats B.; Bertilsson, Stefan; Bravo, Andrea G.;

Abstract

Peatlands are generally important sources of methylmercury (MeHg) to adjacent aquatic ecosystems, increasing the risk of human and wildlife exposure to this highly toxic compound. While microorganisms play important roles in mercury (Hg) geochemical cycles where they directly and indirectly affect MeHg formation in peatlands, potential linkages between net MeHg formation and microbial communities involving these microorganisms remain unclear. To address this gap, microbial community composition and specific marker gene transcripts were investigated along a trophic gradient in a geographically constrained peatland chronosequence. Our results showed a clear spatial pattern in microbial community composition along the gradient that was highly driven by peat soil properties and significantly associated with net MeHg formation as approximated by MeHg concentration and %MeHg of total Hg concentration. Known fermentative, syntrophic, methanogenic and iron-reducing metabolic guilds had the strong positive correlations to net MeHg formation, while methanotrophic and methylotrophic microorganisms were negatively correlated. Our results indicated that sulfate reducers did not have a key role in net MeHg formation. Microbial activity as interpreted from 16S rRNA sequences was significantly correlated with MeHg and %MeHg. Our findings shed new light on the role of microbial community in net MeHg formation of peatlands that undergo ontogenetic change.

Keywords

Microbial Community; Mercury; MeHg; Mercury methylation; Peatland trophic gradient

Published in

Journal of Hazardous Materials

2023, volume: 442, article number: 130057
Publisher: ELSEVIER

Authors' information

Wang, Baolin
Chinese Academy of Sciences
Wang, Baolin
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Hu, Haiyan
Chinese Academy of Sciences
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Bjorn, Erik
Umea University
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Bravo, Andrea G.
CSIC - Centro Mediterraneo de Investigaciones Marinas y Ambientales (CMIMA)

UKÄ Subject classification

Environmental Sciences

Publication Identifiers

DOI: https://doi.org/10.1016/j.jhazmat.2022.130057

URI (permanent link to this page)

https://res.slu.se/id/publ/119557