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Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN.

Morrill PL, Brazelton WJ, Kohl L, Rietze A, Miles SM, Kavanagh H, Schrenk MO, Ziegler SE, Lang SQ - Front Microbiol (2014)

Bottom Line: Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present.The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰.This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth Sciences, Memorial University St. John's, NL, Canada.

ABSTRACT
Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO) utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. CO was consumed in the live experiments but not in the killed controls and the residual CO in the live experiments became enriched in (13)C. The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰. Phospholipid fatty acid concentrations and δ(13)C values suggest limited incorporation of carbon from CO into microbial lipids. This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth. Environmental DNA sequencing of spring fluids collected at the same time as the addition experiments yielded a large proportion of Hydrogenophaga-related sequences, which is consistent with previous metagenomic data indicating the potential for these taxa to utilize CO.

No MeSH data available.


Taxonomic classification of 16S rRNA amplicon sequences derived from fluids and sediments collected from the WHC2 pool and an upstream surface water source. The Comamonadaceae family of Betaproteobacteria dominate both fluids and sediments from the WHC2 pool. Each colored slice represents the proportion of sequences assigned to each taxonomic family. The most abundant families are labeled; those that overlap multiple slices refer to the left-most slice where the family's name begins. For clarity's sake, not all families are labeled, but complete taxonomic classifications of all samples and sequences are available in the supplementary material.
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Figure 2: Taxonomic classification of 16S rRNA amplicon sequences derived from fluids and sediments collected from the WHC2 pool and an upstream surface water source. The Comamonadaceae family of Betaproteobacteria dominate both fluids and sediments from the WHC2 pool. Each colored slice represents the proportion of sequences assigned to each taxonomic family. The most abundant families are labeled; those that overlap multiple slices refer to the left-most slice where the family's name begins. For clarity's sake, not all families are labeled, but complete taxonomic classifications of all samples and sequences are available in the supplementary material.

Mentions: Taxonomic classification of all sequences was performed using the SILVA reference alignment (SSURefv115) and taxonomy outline (Pruesse et al., 2007) using the mothur software platform (v.1.32.1) (Schloss et al., 2009). Figure 2 and supplementary material were generated in R (v.3.1.0) with the phyloseq package (v.1.9.4) (McMurdie and Holmes, 2013) using the taxonomic counts generated by mothur. Family-level classifications are shown in Figure 2 and supplementary material because the most common sequences could not be classified at lower taxonomic levels. MBL-generated sequences are freely available at the VAMPS database (http://vamps.mbl.edu) under the project code DCO_BRZ. All EMP-generated sequences are available via their database at http://www.microbio.me/emp under EMP Project ID 713: Serpentinite Seeps.


Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN.

Morrill PL, Brazelton WJ, Kohl L, Rietze A, Miles SM, Kavanagh H, Schrenk MO, Ziegler SE, Lang SQ - Front Microbiol (2014)

Taxonomic classification of 16S rRNA amplicon sequences derived from fluids and sediments collected from the WHC2 pool and an upstream surface water source. The Comamonadaceae family of Betaproteobacteria dominate both fluids and sediments from the WHC2 pool. Each colored slice represents the proportion of sequences assigned to each taxonomic family. The most abundant families are labeled; those that overlap multiple slices refer to the left-most slice where the family's name begins. For clarity's sake, not all families are labeled, but complete taxonomic classifications of all samples and sequences are available in the supplementary material.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230201&req=5

Figure 2: Taxonomic classification of 16S rRNA amplicon sequences derived from fluids and sediments collected from the WHC2 pool and an upstream surface water source. The Comamonadaceae family of Betaproteobacteria dominate both fluids and sediments from the WHC2 pool. Each colored slice represents the proportion of sequences assigned to each taxonomic family. The most abundant families are labeled; those that overlap multiple slices refer to the left-most slice where the family's name begins. For clarity's sake, not all families are labeled, but complete taxonomic classifications of all samples and sequences are available in the supplementary material.
Mentions: Taxonomic classification of all sequences was performed using the SILVA reference alignment (SSURefv115) and taxonomy outline (Pruesse et al., 2007) using the mothur software platform (v.1.32.1) (Schloss et al., 2009). Figure 2 and supplementary material were generated in R (v.3.1.0) with the phyloseq package (v.1.9.4) (McMurdie and Holmes, 2013) using the taxonomic counts generated by mothur. Family-level classifications are shown in Figure 2 and supplementary material because the most common sequences could not be classified at lower taxonomic levels. MBL-generated sequences are freely available at the VAMPS database (http://vamps.mbl.edu) under the project code DCO_BRZ. All EMP-generated sequences are available via their database at http://www.microbio.me/emp under EMP Project ID 713: Serpentinite Seeps.

Bottom Line: Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present.The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰.This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth Sciences, Memorial University St. John's, NL, Canada.

ABSTRACT
Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO) utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. CO was consumed in the live experiments but not in the killed controls and the residual CO in the live experiments became enriched in (13)C. The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰. Phospholipid fatty acid concentrations and δ(13)C values suggest limited incorporation of carbon from CO into microbial lipids. This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth. Environmental DNA sequencing of spring fluids collected at the same time as the addition experiments yielded a large proportion of Hydrogenophaga-related sequences, which is consistent with previous metagenomic data indicating the potential for these taxa to utilize CO.

No MeSH data available.