Aarhus University Seal / Aarhus Universitets segl

Bo Barker Jørgensen

Formate, acetate, and propionate as substrates for sulfate reduction in sub-arctic sediments of Southwest Greenland

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Standard

Formate, acetate, and propionate as substrates for sulfate reduction in sub-arctic sediments of Southwest Greenland. / Glombitza, Clemens; Jaussi, Marion; Røy, Hans; Seidenkrantz, Marit-Solveig; Lomstein, Bente Aagaard; Jørgensen, Bo Barker.

In: Frontiers in Microbiology, Vol. 6, No. AUG, 846, 24.08.2015.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Harvard

APA

CBE

MLA

Vancouver

Author

Bibtex

@article{dc345e83205441a4944941839ce44494,
title = "Formate, acetate, and propionate as substrates for sulfate reduction in sub-arctic sediments of Southwest Greenland",
abstract = "Volatile fatty acids (VFAs) are key intermediates in the anaerobic mineralization of organic matter in marine sediments. We studied the role of VFAs in the carbon and energy turnover in the sulfate reduction zone of sediments from the sub-arctic Godth{\aa}bsfjord (SW Greenland) and the adjacent continental shelf in the NE Labrador Sea. VFA porewater concentrations were measured by a new two-dimensional ion chromatography-mass spectrometry method that enabled the direct analysis of VFAs without sample pretreatment. VFA concentrations were low and surprisingly constant (4–6 μmol L−1 for formate and acetate, and 0.5 μmol L−1 for propionate) throughout the sulfate reduction zone. Hence, VFAs are turned over while maintaining a stable concentration that is suggested to be under a strong microbial control. Estimated mean diffusion times of acetate between neighboring cells were <1 s, whereas VFA turnover times increased from several hours at the sediment surface to several years at the bottom of the sulfate reduction zone. Thus, diffusion was not limiting the VFA turnover. Despite constant VFA concentrations, the Gibbs energies (ΔGr) of VFA-dependent sulfate reduction decreased downcore, from −28 to −16 kJ (mol formate)−1, −68 to −31 kJ (mol acetate)−1, and −124 to −65 kJ (mol propionate)−1. Thus, ΔGr is apparently not determining the in-situ VFA concentrations directly. However, at the bottom of the sulfate zone of the shelf station, acetoclastic sulfate reduction might operate at its energetic limit at ~ −30 kJ (mol acetate)−1. It is not clear what controls VFA concentrations in the porewater but cell physiological constraints such as energetic costs of VFA activation or uptake could be important. We suggest that such constraints control the substrate turnover and result in a minimum ΔGr that depends on cell physiology and is different for individual substrates.",
keywords = " volatile fatty acids, porewate, thermodynamics, Gibbs energy, minimum energy requirement, acetate diffusion, energy turnover, turnover rates",
author = "Clemens Glombitza and Marion Jaussi and Hans R{\o}y and Marit-Solveig Seidenkrantz and Lomstein, {Bente Aagaard} and J{\o}rgensen, {Bo Barker}",
year = "2015",
month = aug,
day = "24",
doi = "10.3389/fmicb.2015.00846",
language = "English",
volume = "6",
journal = "Frontiers in Microbiology",
issn = "1664-302X",
publisher = "Frontiers Media S.A",
number = "AUG",

}

RIS

TY - JOUR

T1 - Formate, acetate, and propionate as substrates for sulfate reduction in sub-arctic sediments of Southwest Greenland

AU - Glombitza, Clemens

AU - Jaussi, Marion

AU - Røy, Hans

AU - Seidenkrantz, Marit-Solveig

AU - Lomstein, Bente Aagaard

AU - Jørgensen, Bo Barker

PY - 2015/8/24

Y1 - 2015/8/24

N2 - Volatile fatty acids (VFAs) are key intermediates in the anaerobic mineralization of organic matter in marine sediments. We studied the role of VFAs in the carbon and energy turnover in the sulfate reduction zone of sediments from the sub-arctic Godthåbsfjord (SW Greenland) and the adjacent continental shelf in the NE Labrador Sea. VFA porewater concentrations were measured by a new two-dimensional ion chromatography-mass spectrometry method that enabled the direct analysis of VFAs without sample pretreatment. VFA concentrations were low and surprisingly constant (4–6 μmol L−1 for formate and acetate, and 0.5 μmol L−1 for propionate) throughout the sulfate reduction zone. Hence, VFAs are turned over while maintaining a stable concentration that is suggested to be under a strong microbial control. Estimated mean diffusion times of acetate between neighboring cells were <1 s, whereas VFA turnover times increased from several hours at the sediment surface to several years at the bottom of the sulfate reduction zone. Thus, diffusion was not limiting the VFA turnover. Despite constant VFA concentrations, the Gibbs energies (ΔGr) of VFA-dependent sulfate reduction decreased downcore, from −28 to −16 kJ (mol formate)−1, −68 to −31 kJ (mol acetate)−1, and −124 to −65 kJ (mol propionate)−1. Thus, ΔGr is apparently not determining the in-situ VFA concentrations directly. However, at the bottom of the sulfate zone of the shelf station, acetoclastic sulfate reduction might operate at its energetic limit at ~ −30 kJ (mol acetate)−1. It is not clear what controls VFA concentrations in the porewater but cell physiological constraints such as energetic costs of VFA activation or uptake could be important. We suggest that such constraints control the substrate turnover and result in a minimum ΔGr that depends on cell physiology and is different for individual substrates.

AB - Volatile fatty acids (VFAs) are key intermediates in the anaerobic mineralization of organic matter in marine sediments. We studied the role of VFAs in the carbon and energy turnover in the sulfate reduction zone of sediments from the sub-arctic Godthåbsfjord (SW Greenland) and the adjacent continental shelf in the NE Labrador Sea. VFA porewater concentrations were measured by a new two-dimensional ion chromatography-mass spectrometry method that enabled the direct analysis of VFAs without sample pretreatment. VFA concentrations were low and surprisingly constant (4–6 μmol L−1 for formate and acetate, and 0.5 μmol L−1 for propionate) throughout the sulfate reduction zone. Hence, VFAs are turned over while maintaining a stable concentration that is suggested to be under a strong microbial control. Estimated mean diffusion times of acetate between neighboring cells were <1 s, whereas VFA turnover times increased from several hours at the sediment surface to several years at the bottom of the sulfate reduction zone. Thus, diffusion was not limiting the VFA turnover. Despite constant VFA concentrations, the Gibbs energies (ΔGr) of VFA-dependent sulfate reduction decreased downcore, from −28 to −16 kJ (mol formate)−1, −68 to −31 kJ (mol acetate)−1, and −124 to −65 kJ (mol propionate)−1. Thus, ΔGr is apparently not determining the in-situ VFA concentrations directly. However, at the bottom of the sulfate zone of the shelf station, acetoclastic sulfate reduction might operate at its energetic limit at ~ −30 kJ (mol acetate)−1. It is not clear what controls VFA concentrations in the porewater but cell physiological constraints such as energetic costs of VFA activation or uptake could be important. We suggest that such constraints control the substrate turnover and result in a minimum ΔGr that depends on cell physiology and is different for individual substrates.

KW - volatile fatty acids

KW - porewate

KW - thermodynamics

KW - Gibbs energy

KW - minimum energy requirement

KW - acetate diffusion

KW - energy turnover

KW - turnover rates

U2 - 10.3389/fmicb.2015.00846

DO - 10.3389/fmicb.2015.00846

M3 - Journal article

C2 - 26379631

VL - 6

JO - Frontiers in Microbiology

JF - Frontiers in Microbiology

SN - 1664-302X

IS - AUG

M1 - 846

ER -