Towards constraining H2 concentration in subseafloor sediment: A proposal for combined analysis by two distinct approaches

Lin, Yu‐Shih; Heuer, Verena B; Goldhammer, Tobias; Kellermann, Matthias Y.; Zabel, Matthias; Hinrichs, Kai‐Uwe

doi:10.1016/j.gca.2011.11.008

Cited by 83 publications

(55 citation statements)

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“…Thermodynamic calculations based on measured formate concentrations suggest that formate could be a substrate of acetogenesis at certain depths in subsurface sediments on the Juan de Fuca Ridge Flank (Lever et al, 2010). Accurate quantifications of hydrogen concentrations in the deep biosphere are fraught with uncertainty, with two different methods yielding results differing by up to two orders of magnitude (Lin et al, 2011). Yet, independent of the method used, measured concentrations exceeding 10 nM are not uncommon (Shipboard Scientific Party, 2003; Lorenson et al, 2006; Expedition 329 Scientists, 2011; Lin et al, 2011), and suggest that even acetogenesis from H 2 –CO 2 is possible in some places, if not widespread.…”

Section: Resultsmentioning

confidence: 99%

“…H 2 concentrations measured during ODP Leg 201 were obtained via an incubation method, which assumes headspace hydrogen to be in equilibrium with dissolved hydrogen in pore fluids after an incubation period (Lovley and Goodwin, 1988; Hoehler et al, 1998). When compared to a new, extraction-based method on the same samples, the incubation method yields concentration measurements that are consistently lower by one to two orders of magnitude (Lin et al, 2011). If in situ concentrations of H 2 in sediments sampled during Leg 201 are one order of magnitude higher than measured previously, this would lower the

Δ G_{r}^{'}

for acetogenesis from H 2 –CO 2 by ~22 kJ mol −1 .…”

Section: Resultsmentioning

confidence: 99%

“…To compensate for the high uncertainty regarding the accuracy of existing H 2 concentration data from below the seafloor, due to the importance of hydrogen as a (co-)substrate in several acetogenesis reactions (Table 1), and due to previously published evidence suggesting acetogenesis via CO 2 reduction with H 2 in the deep subsurface (Heuer et al, 2009), two hydrogen concentrations were used, 0.1 nM and 1 μM. These concentrations include the range measured across a wide range of organic-rich to ultra-oligotrophic subsurface sites during ocean drilling program (ODP) Legs 201 and 204, IODP Expedition 329, and Meteor Expedition M76 to the Benguela Upwelling Regime (Shipboard Scientific Party, 2003; Lorenson et al, 2006; Expedition 329 Scientists, 2011; Lin et al, 2011). For acetogenesis reactions involving H 2 as a co-substrate, 1 μM H 2 should be non-limiting.…”

Section: Methodsmentioning

confidence: 99%

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Acetogenesis in the Energy-Starved Deep Biosphere – A Paradox?

Lever¹

2012

Front. Microbio.

118

105

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Under anoxic conditions in sediments, acetogens are often thought to be outcompeted by microorganisms performing energetically more favorable metabolic pathways, such as sulfate reduction or methanogenesis. Recent evidence from deep subseafloor sediments suggesting acetogenesis in the presence of sulfate reduction and methanogenesis has called this notion into question, however. Here I argue that acetogens can successfully coexist with sulfate reducers and methanogens for multiple reasons. These include (1) substantial energy yields from most acetogenesis reactions across the wide range of conditions encountered in the subseafloor, (2) wide substrate spectra that enable niche differentiation by use of different substrates and/or pooling of energy from a broad range of energy substrates, (3) reduced energetic cost of biosynthesis among acetogens due to use of the reductive acetyl CoA pathway for both energy production and biosynthesis coupled with the ability to use many organic precursors to produce the key intermediate acetyl CoA. This leads to the general conclusion that, beside Gibbs free energy yields, variables such as metabolic strategy and energetic cost of biosynthesis need to be taken into account to understand microbial survival in the energy-depleted deep biosphere.

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Section: Resultsmentioning

confidence: 99%

Δ G_{r}^{'}

for acetogenesis from H 2 –CO 2 by ~22 kJ mol −1 .…”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Acetogenesis in the Energy-Starved Deep Biosphere – A Paradox?

Lever¹

2012

Front. Microbio.

118

105

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“…Downhole temperature measurements from Expedition 311 have been reported (83). Concentrations of H2 were assumed to be within the range of 2-60 nM, which is typical of marine sediments (84). The C1/C2 data are from Pohlman et al (3).…”

Section: Guaymas Basin Hydrothermal System (Rebecca's Roost Vent) Gumentioning

confidence: 99%

Nonequilibrium clumped isotope signals in microbial methane

Wang

Gruen

Lollar

et al. 2015

Science

Self Cite

213

338

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What controls clumped isotopes? Stable isotopes of a molecule can clump together in several combinations, depending on their mass. Even for simple molecules such as O 2 , which can contain 16 O, 17 O, and 18 O in various combinations, clumped isotopes can potentially reveal the temperatures at which molecules form. Away from equilibrium, however, the pattern of clumped isotopes may reflect a complex array of processes. Using high-resolution gas-phase mass spectrometry, Yeung et al. found that biological factors influence the clumped isotope signature of oxygen produced during photosynthesis (see the Perspective by Passey). Similarly, Wang et al. showed that away from equilibrium, kinetic effects causing isotope clumping can lead to overestimation of the temperature at which microbially produced methane forms. Science , this issue p. 431; p. 428; see also p. 394

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“…Downhole temperature measurements from Expedition 311 have been reported (Riedel et al, 2006). Concentrations of H 2 were assumed to be within the range of 2-60 nM, which is typical of marine sediments (Lin et al, 2012). The C 1 /C 2 data are from Pohlman et al (2009).…”

Section: Model Of Isotopologue Systematics During Microbial Methanogementioning

confidence: 99%

The geochemistry of methane isotopologues

Wang¹

2017

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This thesis documents the origin, distribution, and fate of methane and several of its isotopic forms on Earth. Using observational, experimental, and theoretical approaches, I illustrate how the relative abundances of 12 CH 4 , 13 CH 4 , 12 CH 3 D, and 13 CH 3 D record the formation, transport, and breakdown of methane in selected settings.Chapter 2 reports precise determinations of 13 CH 3 D, a "clumped" isotopologue of methane, in samples collected from various settings representing many of the major sources and reservoirs of methane on Earth. The results show that the information encoded by the abundance of 13 CH 3 D enables differentiation of methane generated by microbial, thermogenic, and abiogenic processes. A strong correlation between clumped-and hydrogen-isotope signatures in microbial methane is identified and quantitatively linked to the availability of H 2 and the reversibility of microbially-mediated methanogenesis in the environment. Determination of 13 CH 3 D in combination with hydrogen-isotope ratios of methane and water provides a sensitive indicator of the extent of C-H bond equilibration, enables fingerprinting of methane-generating mechanisms, and in some cases, supplies direct constraints for locating the waters from which migrated gases were sourced. Chapter 3 applies this concept to constrain the origin of methane in hydrothermal fluids from sediment-poor vent fields hosted in mafic and ultramafic rocks on slow-and ultraslow-spreading mid-ocean ridges. The data support a hypogene model whereby methane forms abiotically within plutonic rocks of the oceanic crust at temperatures above ca. 300• C during respeciation of magmatic volatiles, and is subsequently extracted during active, convective hydrothermal circulation. Chapter 4 presents the results of culture experiments in which methane is oxidized in the presence of O 2 by the bacterium Methylococcus capsulatus strain Bath. The results show that the clumped isotopologue abundances of partially-oxidized methane can be predicted from knowledge of 13 C/ 12 C and D/H isotope fractionation factors alone.: Shuhei Ono, Ph.D. Acknowledgments I fear that this section will not do justice to the people I have not the space to thank individually. Alas, here goes. To those whose names are not specifically listed here, thank you too. I wish first to thank Shuhei Ono. The work this thesis represents could not have happened without his bold vision and the license to explore and question that working in his lab afforded. His unbridled optimism, breadth of scientific curiosity, personal integrity, and accessibility to his personnel are traits I one day hope to emulate. I thank him for his nonjudgmental yet appropriately measured support of many of my ideas-even those that led nowhere-, for believing in me even when I found it difficult to do so myself, and for teaching me to change pump oil, build vacuum lines, and drink Icelandic vodka.I also wish to thank my thesis committee members Jeff Seewald, Roger Summons, and John Pohlman, for their in...

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Towards constraining H2 concentration in subseafloor sediment: A proposal for combined analysis by two distinct approaches

Cited by 83 publications

References 63 publications

Acetogenesis in the Energy-Starved Deep Biosphere – A Paradox?

Acetogenesis in the Energy-Starved Deep Biosphere – A Paradox?

Nonequilibrium clumped isotope signals in microbial methane

The geochemistry of methane isotopologues

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