Biology subjects

Price, R. E.

Publications and source records attributed to Price, R. E..

3 recordsLinked to original sources

bioRxiv2025

The microbiology and geochemistry of the shallow-water hydrothermal vents of the Gulf of Naples, Italy

Shallow-water hydrothermal vents are dynamic ecosystems that occur below 200 m in tectonically active regions of the planet. While their geochemical composition has been investigated in several locations, knowledge about the microbial diversity they harbour remains scarce. Moreover, the relationships between hydrothermal fluid chemistry, geological settings and microbial community structure in shallow vents have not been explored in detail. Here, we investigate the interplay between fluid geochemistry and microbial diversity in two underwater volcanic regions in the Gulf of Naples, Italy, one under the influence of the Somma-Vesuvio volcano and the other located within the underwater portion of the Campi Flegrei caldera. By combining 16S rRNA amplicon sequencing with geochemical measurements, and by contextualizing it with previous geochemical measurements done in the region, we found that hydrothermal fluid chemistry, influenced by the geological setting where the vents are hosted, plays a key role in shaping microbial ecological niches, and imposes strong selective pressures on the resident microbial communities. We additionally describe two new shallow vent sites, contributing to the characterization of the hydrothermalism in the area and unveiling the biodiversity associated with shallow-water hydrothermalism in the region.

microbiology↗

bioRxiv2025

Cultivating microbial communities from the serpentinite-hosted Prony Bay Hydrothermal Field on different carbon sources in hydrogen-fed bioreactors

The primary source of carbon is one of the most fundamental questions regarding the development of microbial communities in serpentinite-hosted systems. The hydration of ultramafic rock to serpentinites generates hydrogen and creates hyper-alkaline conditions that deplete the environment of dissolved inorganic carbon. Metagenomic studies suggest that serpentinite-hosted microbial communities depend on the local redissolution of bicarbonate as well as on small organic molecules produced by abiotic reactions associated with serpentinization. To test these hypotheses, microbial consortia collected from the Prony Bay hydrothermal field were grown under anoxic conditions in hydrogen-fed bioreactors using bicarbonate, formate, acetate, or glycine as the sole carbon source. In contrast to glycine, the other three carbon substrates allowed the growth of microbial consortia characterized by significant enrichment of individual taxa. Surprisingly, these taxa were dominated by microbial genera characterized as aerobic rather than anaerobic as expected. We propose that an intricate feedback loop between autotrophic and heterotrophic foundation species facilitates the establishment of serpentinite-hosted shallow subsurface ecosystems. Bicarbonate-fixing Meiothermus and Hydrogenophaga, as well as formate-fixing Meiothermus, Thioalkalimicrobium, and possibly a novel genotype of Roseibaca might produce organic compounds for heterotrophs at the first trophic level. In addition, the base of the trophic network may include heterotrophic Roseibaca, Acetoanaerobium, and Meiothermus species producing CO2 from acetate for a more diverse community of autotrophs. The cultivated archaeal community is expected to recycle CH4 and CO2 between Methanomicrobiales and Methanosarcinales with putative Woesearchaeales symbionts.

microbiology↗

bioRxiv2022

Quantifying the bioavailable energy in an ancient hydrothermal vent on Mars and a modern Earth-based analogue.

Putative alkaline hydrothermal systems on Noachian Mars were potentially habitable environments for microorganisms. However, the types of reactions that could have fueled microbial life in such systems and the amount of energy available from them have not been quantitatively constrained. In this study, we use thermodynamic modeling to calculate which catabolic reactions could have supported ancient life in a saponite-precipitating hydrothermal vent system in the Eridania basin on Mars. To further evaluate what this could mean for microbial life, we evaluated the energy potential of an analogue site in Iceland, the Strytan Hydrothermal Field (SHF). Results show that out of the 85 relevant redox reactions that were considered, the highest energy-yielding reactions in the Eridania hydrothermal system were dominated by methane formation. By contrast, Gibbs energy calculations carried out for Strytan indicate that the most energetically favorable reactions are CO2 and O2 reduction coupled to H2 oxidation. In particular, our calculations indicate that an ancient hydrothermal system within the Eridania basin could have been a habitable environment for methanogens using NH4+ as an electron acceptor. Differences in Gibbs energies between the two systems were largely determined by oxygen - its presence on Earth and absence on Mars. However, Strytan can serve as a useful analogue for Eridania when studying methane producing reactions that do not involve O2.

microbiology↗