Using Cathodic Poised Potential Experiments to Investigate Extracellular Electron Transport in the Crustal Deep Biosphere of North Pond, Mid-Atlantic Ridge

Jones, Rose M.; D’Angelo, Timothy; Orcutt, Beth N.

doi:10.3389/fenvs.2020.00011

Cited by 3 publications

(6 citation statements)

References 119 publications

(168 reference statements)

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“…Enrichment cultures of electrotrophic communities are obtained on electrodes and show a specific enrichment of Archaea belonging to the Thermococcales and Archaeoglobales orders in microbial electrolysis cells (specially designed bio-electrochemical system) under hyperthermophilic conditions (80 °C) (Pillot et al 2018). In an environmental context other than hydrothermal sources, high-potential cathodic experiments were also conducted to enrich microorganisms in North Pond crustal samples capable of extracellular electron transport (EET) (Jones et al 2020). Subsequent analyses of these incubations, using meta-omic analysis, fluorescence in situ hybridization coupled to secondary ion mass spectrometry (FISH-SIMS), isotope labeling experiments, and chemical analysis were necessary to understand the microbial community and metabolic pathways.…”

Section: Perspectivesmentioning

confidence: 99%

Microorganisms from deep-sea hydrothermal vents

Zeng

Alain

Shao

2021

Mar Life Sci Technol

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With a rich variety of chemical energy sources and steep physical and chemical gradients, hydrothermal vent systems offer a range of habitats to support microbial life. Cultivation-dependent and independent studies have led to an emerging view that diverse microorganisms in deep-sea hydrothermal vents live their chemolithoautotrophic, heterotrophic, or mixotrophic life with versatile metabolic strategies. Biogeochemical processes are mediated by microorganisms, and notably, processes involving or coupling the carbon, sulfur, hydrogen, nitrogen, and metal cycles in these unique ecosystems. Here, we review the taxonomic and physiological diversity of microbial prokaryotic life from cosmopolitan to endemic taxa and emphasize their significant roles in the biogeochemical processes in deep-sea hydrothermal vents. According to the physiology of the targeted taxa and their needs inferred from meta-omics data, the media for selective cultivation can be designed with a wide range of physicochemical conditions such as temperature, pH, hydrostatic pressure, electron donors and acceptors, carbon sources, nitrogen sources, and growth factors. The application of novel cultivation techniques with real-time monitoring of microbial diversity and metabolic substrates and products are also recommended.

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Section: Perspectivesmentioning

confidence: 99%

Microorganisms from deep-sea hydrothermal vents

Zeng

Alain

Shao

2021

Mar Life Sci Technol

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“…Effluents from FLOCS colonization chambers were continuously collected in OsmoSamplers (Jannasch et al ., 2004) to determine solute concentration changes over time and confirm fluid origin and reaction progression. All experiments were recovered in October 2017 and processed as detailed in the Appendix S1 following protocols of recent studies (Ramírez et al ., 2019; Jones et al ., 2020). After verifying DNA extraction protocols on test samples (Table S2, Figs S3 and S4), the microbial communities on the colonized materials were compared to each other, and also to prior community data from rock and fluid samples from this and other study sites, to determine the degree that inoculation origin, redox and nutrient conditions, mineral type, length of exposure or other factors contribute to biogeographic patterning.…”

Section: Introductionmentioning

confidence: 99%

Microbe‐mineral biogeography from multi‐year incubations in oceanic crust at North Pond, Mid‐Atlantic Ridge

Orcutt

D’Angelo

Wheat

et al. 2021

Environmental Microbiology

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Subseafloor oceanic crust is a vast yet poorly sampled habitat for life. Recent studies suggest that microbial composition in crustal habitats is variable in space and time, but biogeographic patterns are difficult to determine due to a paucity of data. To address this, we deployed hundreds of mineral colonization experiments at and below the seafloor for 4-6 years at North Pond, a borehole observatory network in cool (<10 C) and oxic oceanic crust on the western flank of the Mid-Atlantic Ridge. The overall community composition of mineral incubations reveals that colonization patterns are site dependent, with no correlation to mineral type. Only a few members of the Thioalkalispiraceae and Thioprofundaceae exhibited a mineral preference pattern, with generally higher abundance on metal sulphides compared to silicates, while taxa of the Gammaproteobacteria and Deltaproteobacteria were common in the colonization experiments. In comparison to datasets from other crustal habitats, broader biogeographic patterns of crustal communities emerge based on crustal habitat type (surface-attached communities versus fluid communities), redox environment and possibly crustal age. These comparisons suggest successional biogeography patterning that might be used as an indicator of how recently permeable pathways were established within oceanic crust.

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“…Further, we also documented the presence of genes associated with iron reduction [mtrCAB (Pitts et al, 2003;Hartshorne et al, 2007;Edwards et al, 2020) within seven of the timepoints, which span 2 years (Figure 1)]. The mtrCAB genes are most closely related to the dissimilatory iron reducer Shewanella benthica (Supplementary File 2), which was also enriched in mineral colonizations from the North Pond aquifer (Jones et al, 2020). We also identified nine MAGs (Tully et al, 2018), encoding copies of genes linked to respiratory iron oxidation or reduction (Supplementary Table 2).…”

Section: Resultsmentioning

confidence: 90%

“…Tully et al (2018) also reconstructed metagenomeassembled genomes (MAGs) affiliated with the iron-oxidizing Zetaproteobacteria, which are known to adapt to fluctuating O 2 concentrations and advective flow regimes (Chiu et al, 2017;Blackwell et al, 2020), further solidifying the presence and significant contribution that iron-oxidizing bacteria make to the aquifer community. Recent mineral colonization and current generation on poised electrodes also demonstrated the presence of iron oxidizing bacteria and provided evidence for their ability to utilize insoluble electron acceptors (Jones et al, 2020).…”

Section: Resultsmentioning

confidence: 99%

“…Other putative iron oxidizers and reducers are shown in Supplementary Table 2. 16S rRNA gene amplicon sequencing presented by Jones et al (2020), showed that Geobacter-related spp. were also enriched on minerals; however, we did not detect any Geobacter-related gene markers for iron reduction (omcS, omcZ, and type IV aromatic/electroactive pili [t4ap]), suggesting that this lineage may be part of the rare biosphere and undetectable with metagenomic approaches, at least in the aquifer fluids.…”

Section: Resultsmentioning

confidence: 99%

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Metagenomic Insights Into the Microbial Iron Cycle of Subseafloor Habitats

et al. 2021

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Microbial iron cycling influences the flux of major nutrients in the environment (e.g., through the adsorptive capacity of iron oxides) and includes biotically induced iron oxidation and reduction processes. The ecological extent of microbial iron cycling is not well understood, even with increased sequencing efforts, in part due to limitations in gene annotation pipelines and limitations in experimental studies linking phenotype to genotype. This is particularly true for the marine subseafloor, which remains undersampled, but represents the largest contiguous habitat on Earth. To address this limitation, we used FeGenie, a database and bioinformatics tool that identifies microbial iron cycling genes and enables the development of testable hypotheses on the biogeochemical cycling of iron. Herein, we survey the microbial iron cycle in diverse subseafloor habitats, including sediment-buried crustal aquifers, as well as surficial and deep sediments. We inferred the genetic potential for iron redox cycling in 32 of the 46 metagenomes included in our analysis, demonstrating the prevalence of these activities across underexplored subseafloor ecosystems. We show that while some processes (e.g., iron uptake and storage, siderophore transport potential, and iron gene regulation) are near-universal, others (e.g., iron reduction/oxidation, siderophore synthesis, and magnetosome formation) are dependent on local redox and nutrient status. Additionally, we detected niche-specific differences in strategies used for dissimilatory iron reduction, suggesting that geochemical constraints likely play an important role in dictating the dominant mechanisms for iron cycling. Overall, our survey advances the known distribution, magnitude, and potential ecological impact of microbe-mediated iron cycling and utilization in sub-benthic ecosystems.

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Using Cathodic Poised Potential Experiments to Investigate Extracellular Electron Transport in the Crustal Deep Biosphere of North Pond, Mid-Atlantic Ridge

Cited by 3 publications

References 119 publications

Microorganisms from deep-sea hydrothermal vents

Microorganisms from deep-sea hydrothermal vents

Microbe‐mineral biogeography from multi‐year incubations in oceanic crust at North Pond, Mid‐Atlantic Ridge

Metagenomic Insights Into the Microbial Iron Cycle of Subseafloor Habitats

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