Validation of neutron-induced reactions on natural carbon using an active target at neutron energies up to 22 MeV at LANSCE

Dissimilatory phosphite oxidation (DPO), a microbial metabolism by which phosphite (HPO32−) is oxidized to phosphate (PO43−), is the most energetically favorable chemotrophic electron-donating process known. Only one DPO organism has been described to date, and little is known about the environmental relevance of this metabolism. In this study, we used 16S rRNA gene community analysis and genome-resolved metagenomics to characterize anaerobic wastewater treatment sludge enrichments performing DPO coupled to CO2reduction. We identified an uncultivated DPO bacterium,CandidatusPhosphitivorax (Ca.P.) anaerolimi strain Phox-21, that belongs to candidate order GW-28 within theDeltaproteobacteria, which has no known cultured isolates. Genes for phosphite oxidation and for CO2reduction to formate were found in the genome ofCa.P. anaerolimi, but it appears to lack any of the known natural carbon fixation pathways. These observations led us to propose a metabolic model for autotrophic growth byCa.P. anaerolimi whereby DPO drives CO2reduction to formate, which is then assimilated into biomass via the reductive glycine pathway.

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Active Target detectors for studies with exotic beams: Present and next future

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/j.nima.2014.10.048 ◽

2015 ◽

Vol 784 ◽

pp. 494-498 ◽

Cited By ~ 18

Author(s):

W. Mittig ◽

S. Beceiro-Novo ◽

A. Fritsch ◽

F. Abu-Nimeh ◽

D. Bazin ◽

...

Keyword(s):

Active Target ◽

Exotic Beams

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Unsupervised learning for identifying events in active target experiments

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/j.nima.2021.165461 ◽

2021 ◽

pp. 165461

Author(s):

R. Solli ◽

D. Bazin ◽

M. Hjorth-Jensen ◽

M.P. Kuchera ◽

R.R. Strauss

Keyword(s):

Unsupervised Learning ◽

Active Target

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Simulating natural carbon sequestration in the Southern Ocean: on uncertainties associated with eddy parameterizations and iron deposition

Biogeosciences ◽

10.5194/bg-14-1561-2017 ◽

2017 ◽

Vol 14 (6) ◽

pp. 1561-1576 ◽

Cited By ~ 3

Author(s):

Heiner Dietze ◽

Julia Getzlaff ◽

Ulrike Löptien

Keyword(s):

Carbon Sequestration ◽

Southern Ocean ◽

Ocean Circulation ◽

Spatial Scales ◽

Carbon Uptake ◽

Comprehensive Understanding ◽

Biogeochemical Models ◽

Anthropogenic Carbon ◽

Natural Carbon ◽

Oceanic Carbon

Abstract. The Southern Ocean is a major sink for anthropogenic carbon. Yet, there is no quantitative consensus about how this sink will change when surface winds increase (as they are anticipated to do). Among the tools employed to quantify carbon uptake are global coupled ocean-circulation–biogeochemical models. Because of computational limitations these models still fail to resolve potentially important spatial scales. Instead, processes on these scales are parameterized. There is concern that deficiencies in these so-called eddy parameterizations might imprint incorrect sensitivities of projected oceanic carbon uptake. Here, we compare natural carbon uptake in the Southern Ocean simulated with contemporary eddy parameterizations. We find that very differing parameterizations yield surprisingly similar oceanic carbon in response to strengthening winds. In contrast, we find (in an additional simulation) that the carbon uptake does differ substantially when the supply of bioavailable iron is altered within its envelope of uncertainty. We conclude that a more comprehensive understanding of bioavailable iron dynamics will substantially reduce the uncertainty of model-based projections of oceanic carbon uptake.

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Recent changes in the global and regional carbon cycle: analysis of first-order diagnostics

Biogeosciences ◽

10.5194/bg-12-835-2015 ◽

2015 ◽

Vol 12 (3) ◽

pp. 835-844 ◽

Cited By ~ 6

Author(s):

P. J. Rayner ◽

A. Stavert ◽

M. Scholze ◽

A. Ahlström ◽

C. E. Allison ◽

...

Keyword(s):

Carbon Cycle ◽

Linear Response ◽

Anthropogenic Emissions ◽

Seasonal Patterns ◽

Atmospheric Concentration ◽

First Order ◽

Northern Summer ◽

Data Points ◽

Natural Carbon ◽

The Tropics

Abstract. We analyse global and regional changes in CO2 fluxes using two simple models, an airborne fraction of anthropogenic emissions and a linear relationship with CO2 concentrations. We show that both models are able to fit the non-anthropogenic (hereafter natural) flux over the length of the atmospheric concentration record. Analysis of the linear model (including its uncertainties) suggests no significant decrease in the response of the natural carbon cycle. Recent data points rather to an increase. We apply the same linear diagnostic to fluxes from atmospheric inversions. Flux responses show clear regional and seasonal patterns driven by terrestrial uptake in the northern summer. Ocean fluxes show little or no linear response. Terrestrial models show clear responses, agreeing globally with the inversion responses, however the spatial structure is quite different, with dominant responses in the tropics rather than the northern extratropics.

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