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Your search keyword '"Girguis, P.R."' showing total 5 results
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5 results on '"Girguis, P.R."'

1. Remarkable Capacity for Anaerobic Oxidation of Methane at High Methane Concentration

Author

Finke, N., Hunter, K.S., Joye, S.B., Teske, A.P., Girguis, P.R., Samarkin, V.A., and Bowles, M.W.

Abstract

Anaerobic oxidation of methane (AOM), a central process in the carbon cycle of anoxic environments, moderates the release of methane from soils and sediments to water bodies and, ultimately, the atmosphere. The regulation of AOM in the environment remains poorly constrained. Here we quantified AOM and sulfate reduction (SR) rates in diverse deep seafloor samples at in situ pressure and methane concentration and discovered that, in some cases, AOM exceeded SR rates by more than four times when methane concentrations were above 5 mM. Methane concentration also affected other carbon-cycling processes (e.g., carbon assimilation) in addition to SR. These results illustrate that substantial amounts of methane may be oxidized independent of SR under in situ conditions, reshaping our view of the capacity and mechanism of AOM in methane-rich environments, including the deep biosphere, where sulfate availability is considered to limit AOM.

Published
2019
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3. Hydrogen is an energy source for hydrothermal vent symbioses

Author

Petersen, J.M., Zielinski, Frank, Pape, T., Seifert, R., Moraru, C., Amann, R., Hourdez, S., Girguis, P.R., Wankel, S.D., Barbe, V., Pelletier, E., Fink, D., Borowski, C., Bach, W., Dubilier, N., Petersen, J.M., Zielinski, Frank, Pape, T., Seifert, R., Moraru, C., Amann, R., Hourdez, S., Girguis, P.R., Wankel, S.D., Barbe, V., Pelletier, E., Fink, D., Borowski, C., Bach, W., and Dubilier, N.

Abstract

The discovery of deep-sea hydrothermal vents in 1977 revolutionized our understanding of the energy sources that fuel primary productivity on Earth. Hydrothermal vent ecosystems are dominated by animals that live in symbiosis with chemosynthetic bacteria. So far, only two energy sources have been shown to power chemosynthetic symbioses: reduced sulphur compounds and methane. Using metagenome sequencing, single-gene fluorescence in situ hybridization, immunohistochemistry, shipboard incubations and in situ mass spectrometry, we show here that the symbionts of the hydrothermal vent mussel Bathymodiolus from the Mid-Atlantic Ridge use hydrogen to power primary production. In addition, we show that the symbionts of Bathymodiolus mussels from Pacific vents have hupL, the key gene for hydrogen oxidation. Furthermore, the symbionts of other vent animals such as the tubeworm Riftia pachyptila and the shrimp Rimicaris exoculata also have hupL. We propose that the ability to use hydrogen as an energy source is widespread in hydrothermal vent symbioses, particularly at sites where hydrogen is abundant.

Published
2011

5. Effects of metabolite uptake on proton-equivalent elimination by two species of deep-sea vestimentiferan tubeworm, Riftia pachyptila and Lamellibrachia cf luymesi: proton elimination is a necessary adaptation to sulfide-oxidizing chemoautotrophic...

Author

Girguis, P.R., Childress, J.J., Freytag, J.K., Klose, K., and Stuber, R.

Subjects
*METABOLITES, *TUBE worms
Abstract

Examines the effects of metabolite uptake on proton-equivalent elimination by species of deep-sea vestimentiferan tubeworm. Association of elimination rates to the rate of sulfide oxidation; Result of prolonged exposure to low environmental oxygen concentrations; Consequences of large and rapid increases in environmental inorganic carbon concentration.

Published
2002

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