Limits...
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.


Stable carbon isotope values of CH4 and CO2 products of 13C-labeled and non-labeled experiments where 13C-labeled bicarbonate, and organic acids were added to each treatment where K represents a killed control, L represents a live experiments, and 13C represents where 13C-labeled substrate was added. The errors bars are the standard deviations of averages of duplicate experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4230201&req=5

Figure 3: Stable carbon isotope values of CH4 and CO2 products of 13C-labeled and non-labeled experiments where 13C-labeled bicarbonate, and organic acids were added to each treatment where K represents a killed control, L represents a live experiments, and 13C represents where 13C-labeled substrate was added. The errors bars are the standard deviations of averages of duplicate experiments.

Mentions: CH4 was detected in only 7 of the 15 experimental treatments (Figure 3). The CH4 was detected in live and killed treatments, as well as 13C-labeled and non-labeled substrate addition treatments. All CH4 had similar values, averaging −26.7 ± 0.7‰, including the 13C-labeled substrate addition experiments. The average δ13CCH4 value from the experiments was indistinguishable from the average δ13CCH4 value, −26.9 ± 0.9‰, (Table 1) determine from field samples. Therefore, there is no clear evidence of microbial production of CH4 using the substrates added in these treatments.


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)

Stable carbon isotope values of CH4 and CO2 products of 13C-labeled and non-labeled experiments where 13C-labeled bicarbonate, and organic acids were added to each treatment where K represents a killed control, L represents a live experiments, and 13C represents where 13C-labeled substrate was added. The errors bars are the standard deviations of averages of duplicate experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Stable carbon isotope values of CH4 and CO2 products of 13C-labeled and non-labeled experiments where 13C-labeled bicarbonate, and organic acids were added to each treatment where K represents a killed control, L represents a live experiments, and 13C represents where 13C-labeled substrate was added. The errors bars are the standard deviations of averages of duplicate experiments.
Mentions: CH4 was detected in only 7 of the 15 experimental treatments (Figure 3). The CH4 was detected in live and killed treatments, as well as 13C-labeled and non-labeled substrate addition treatments. All CH4 had similar values, averaging −26.7 ± 0.7‰, including the 13C-labeled substrate addition experiments. The average δ13CCH4 value from the experiments was indistinguishable from the average δ13CCH4 value, −26.9 ± 0.9‰, (Table 1) determine from field samples. Therefore, there is no clear evidence of microbial production of CH4 using the substrates added in these treatments.

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.