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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #416096
Research Project: Managing Manure as a Soil Resource for Improved Biosecurity, Nutrient Availability, and Soil Sustainability

Location: Agroecosystem Management Research

Title: Microbial methane production from calcium carbonate at moderately alkaline pH

Author
item FLORE, NICOLE - University Of Nebraska
item KOHTZ, ANTHONY - University Of Nebraska
item Miller, Daniel
item ANTONY-BABU,, SANJAY - University Of Nebraska
item PAN, DONALD - University Of Nebraska
item LAHEY, CAITLIN - University Of Nebraska
item HUANG, XI - University Of Nebraska
item LU, YONGFENG - University Of Nebraska
item BUAN, NICOLE - University Of Nebraska
item WEBER, KARRIE - University Of Nebraska

Submitted to: Communications Earth & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2025
Publication Date: 2/4/2025
Citation: Flore, N.A., Kohtz, A.J., Miller, D.N., Antony-Babu,, S., Pan, D., Lahey, C., Huang, X., Lu, Y., Buan, N.R., Weber, K. 2025. Microbial methane production from calcium carbonate at moderately alkaline pH. Communications Earth & Environment. 6. Article 85. https://doi.org/10.1038/s43247-025-02057-y.
DOI: https://doi.org/10.1038/s43247-025-02057-y

Interpretive Summary: Carbonate minerals are considered a stable carbon reservoir under alkaline conditions. This researcher shows calcium carbonate can be the sole inorganic carbon source at moderately alkaline pH for microbes enriched from alkaline, saline wetland soil. Provided with calcium carbonate as the sole source of inorganic carbon, methane and aqueous calcium concentrations increased as hydrogen was depleted. Microbial cells were observed iassociated with carbonate mineral by microscopy. Genome analysis of the microbial community identified a Methanobacterium species capable of producing methane using hydrogen in addition to five other bacterial species. These results demonstrate carbonate minerals can serve as an inorganic carbon source for methane production, leading to carbonate loss under stable alkaline conditions potentially impacting carbonate mineral stability in environmental systems.

Technical Abstract: Carbonate minerals are considered a metastable carbon reservoir under alkaline conditions. Here, we demonstrate the use of calcium carbonate as a sole inorganic carbon source at moderately alkaline pH for a methanogenic microbial community enriched from alkaline, saline wetland soil. In reactors amended with calcium carbonate as the sole source of inorganic carbon, methane and aqueous calcium concentrations increased concurrent with headspace hydrogen depletion. Cells were observed in association with the carbonate mineral matrix via coherent anti-Stokes Raman scattering and two-photon excitation fluorescence microscopy. Genome-resolved metagenomics of the enrichment community confirmed the presence of a methanogen (Methanobacterium sp.) with the metabolic potential for hydrogenotrophic methanogenesis in addition to five bacterial community members. These results demonstrate carbonate minerals can serve as an inorganic carbon source for hydrogenotrophic methanogenesis, leading to mineral dissolution under stable alkaline conditions. As such, hydrogenotrophic methanogens may impact carbon biogeochemistry and carbonate mineral stability in environmental systems.