ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Microbiological Chemistry and Geomicrobiology
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1671749
This article is part of the Research TopicMicrobial Interactions with Metals/Minerals: From Environmental Aspects to ApplicationsView all 4 articles
Anaerobic Prokaryotic Processes Drive Manganese Release in a Drinking Water Reservoir
Provisionally accepted
- 1Department Biology, Institute for Integrated Natural Sciences, University of Koblenz, Koblenz, Germany
- 2Wahnbach Reservoir Association (Wahnbachtalsperrenverband – WTV), Siegburg, Germany
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Introduction: Elevated manganese (Mn) concentrations in drinking water reservoirs present challenges for raw water treatment. During thermal stratification, a shift from oxic to anoxic conditions at the sediment-water interface intensifies the release of dissolved Mn into the water column. Methods: High-throughput amplicon sequencing of 16S rRNA genes was used to identify the prokaryotic community in sediments of the Wahnbach Reservoir, examining abundance, diversity, and potential metabolic processes concerning key physicochemical parameters. In addition, cultivation-based methods clarified the role of Mn cycling and related biogeochemical processes. Results: Sediment analyses revealed high sedimentary Mn contents and elevated Mn2+ concentrations in pore water. Bioinformatic analysis of 16S rRNA gene sequences revealed a diverse prokaryotic community involved in Mn cycling and competing redox processes, both in sediment samples and enrichment cultures selective for Mn-transforming organisms. Dominant metabolic processes included anaerobic respiration, such as methanogenesis and the reduction of Mn, Fe, sulfate, as well as nitrate, alongside oxidative processes like nitrification and methanotrophy. Cultivation-based approaches confirmed the relevance of these processes and uncovered interconnections among them through the enrichment of specific genera, including Rhodoferax, a typical Mn reducer, Ellin6067, an ammonium oxidizer, and the methanogen Methanosarcina. Discussion: Seasonal oxygen depletion promotes the release of Mn and Fe from sediments, with Mn(IV) and Fe(III) reduction occurring under increasingly reducing conditions and contributing to metal cycling and redox zonation. This study highlights the dynamic interaction between physicochemical gradients and prokaryotic community structure that drives Mn transformation in stratified freshwater systems.
Keywords: manganese redox cycling, Sediment biogeochemistry, 16S rRNA gene sequencing, prokaryotic metabolic processes, Drinking water reservoir
Received: 23 Jul 2025; Accepted: 15 Sep 2025.
Copyright: © 2025 Hahn, Vriesen, Packroff, Meier and Manz. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Lea Hahn, leahahn@uni-koblenz.de
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