scholarly journals Metabolic exchange between pathways for isoprenoid synthesis and implications for biosynthetic hydrogen isotope fractionation

2021 ◽  
Author(s):  
S. Nemiah Ladd ◽  
Daniel B. Nelson ◽  
Ines Bamberger ◽  
L. Erik Daber ◽  
Jürgen Kreuzwieser ◽  
...  
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Metabolic Exchange

scholarly journals Unravelling the process of petroleum hydrocarbon biodegradation in different filter materials of constructed wetlands by stable isotope fractionation and labelling studies

2021 ◽  
Author(s):  
Andrea Watzinger ◽  
Melanie Hager ◽  
Thomas Reichenauer ◽  
Gerhard Soja ◽  
Paul Kinner
Keyword(s):  
Stable Isotope ◽  
Constructed Wetlands ◽  
Hydrogen Isotope ◽  
Petroleum Hydrocarbon ◽  
Isotope Fractionation ◽  
Isotope Effects ◽  
Filter Material ◽  
Hydrocarbon Biodegradation ◽  
Stable Isotope Fractionation ◽  
Filter Materials

AbstractMaintaining and supporting complete biodegradation during remediation of petroleum hydrocarbon contaminated groundwater in constructed wetlands is vital for the final destruction and removal of contaminants. We aimed to compare and gain insight into biodegradation and explore possible limitations in different filter materials (sand, sand amended with biochar, expanded clay). These filters were collected from constructed wetlands after two years of operation and batch experiments were conducted using two stable isotope techniques; (i) carbon isotope labelling of hexadecane and (ii) hydrogen isotope fractionation of decane. Both hydrocarbon compounds hexadecane and decane were biodegraded. The mineralization rate of hexadecane was higher in the sandy filter material (3.6 µg CO2 g−1 day−1) than in the expanded clay (1.0 µg CO2 g−1 day−1). The microbial community of the constructed wetland microcosms was dominated by Gram negative bacteria and fungi and was specific for the different filter materials while hexadecane was primarily anabolized by bacteria. Adsorption / desorption of petroleum hydrocarbons in expanded clay was observed, which might not hinder but delay biodegradation. Very few cases of hydrogen isotope fractionation were recorded in expanded clay and sand & biochar filters during decane biodegradation. In sand filters, decane was biodegraded more slowly and hydrogen isotope fractionation was visible. Still, the range of observed apparent kinetic hydrogen isotope effects (AKIEH = 1.072–1.500) and apparent decane biodegradation rates (k = − 0.017 to − 0.067 day−1) of the sand filter were low. To conclude, low biodegradation rates, small hydrogen isotope fractionation, zero order mineralization kinetics and lack of microbial biomass growth indicated that mass transfer controlled biodegradation.

scholarly journals Mass spectrometric measurement of hydrogen isotope fractionation for the reactions of chloromethane with OH and Cl

2018 ◽  
Author(s):  
Frank Keppler ◽  
Enno Bahlmann ◽  
Markus Greule ◽  
Heinz Friedrich Schöler ◽  
Julian Wittmer ◽  
...  
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Isotope Effects ◽  
Isotope Analysis ◽  
Isotope Ratio Mass Spectrometry ◽  
Detailed Knowledge ◽  
Mass Spectrometric Measurement ◽  
Isotopic Analyses ◽  
Chlorine Radicals ◽  
Stable Hydrogen Isotope

Abstract. Chloromethane (CH3Cl) is an important provider of chlorine to the stratosphere but yet lacks detailed knowledge of its budget. Stable isotope analysis is potentially a powerful tool to constrain CH3Cl flux estimates. The largest degree of isotope fractionation is expected to occur for deuterium in CH3Cl in the hydrogen abstraction reactions with its main sink reactant tropospheric OH and its minor sink reactant Cl atoms. We determined the isotope fractionation by stable hydrogen isotope analysis of the fraction of CH3Cl remaining after reaction with hydroxyl and chlorine radicals in a 3.5 m3 Teflon smog-chamber at 293 ± 1 K. We measured the increasing stable hydrogen isotope values of the unreacted CH3Cl using compound specific thermal conversion isotope ratio mass spectrometry. The isotope fractionations of CH3Cl for the reactions with hydroxyl and chlorine radicals were found to be −242 ± 7 mUr (or ‰) and −280 ± 11 mUr, respectively. For comparison, we performed similar experiments using methane (CH4) as the target compound with OH and obtained a fractionation constant of −205 ± 6 mUr which is in good agreement with values previously reported. The observed large kinetic isotope effects are helpful when employing isotopic analyses of CH3Cl in the atmosphere to improve our knowledge of its atmospheric budget.

scholarly journals Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

2017 ◽  
Vol 14 (24) ◽  
pp. 5693-5704 ◽  
Author(s):  
Gabriella M. Weiss ◽  
Eva Y. Pfannerstill ◽  
Stefan Schouten ◽  
Jaap S. Sinninghe Damsté ◽  
Marcel T. J. van der Meer
Keyword(s):  
Light Intensity ◽  
Environmental Conditions ◽  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Emiliania Huxleyi ◽  
High Light Intensity ◽  
High Light ◽  
Light Conditions ◽  
Low Light ◽  
Long Chain

Abstract. Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

3D-CSIA: Carbon, Chlorine, and Hydrogen Isotope Fractionation in Transformation of TCE to Ethene by aDehalococcoidesCulture

2013 ◽  
Vol 47 (17) ◽  
pp. 9668-9677 ◽  
Author(s):  
Tomasz Kuder ◽  
Boris M. van Breukelen ◽  
Mindy Vanderford ◽  
Paul Philp
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Fractionation

Hydrogen-isotope fractionation in aluminum hydroxides: Synthesis products versus natural samples from bauxites

2001 ◽  
Vol 65 (9) ◽  
pp. 1391-1398 ◽  
Author(s):  
Frédéric Vitali ◽  
Fred J Longstaffe ◽  
Michael I Bird ◽  
Karie Lyne Gage ◽  
W.Glen E Caldwell
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Aluminum Hydroxides

Carbon and hydrogen isotope fractionation resulting from anaerobic methane oxidation

1988 ◽  
Vol 2 (3) ◽  
pp. 279-288 ◽  
Author(s):  
M. J. Alperin ◽  
W. S. Reeburgh ◽  
M. J. Whiticar
Keyword(s):  
Methane Oxidation ◽  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Anaerobic Methane Oxidation ◽  
Carbon And Hydrogen Isotope

Carbon and hydrogen isotope fractionation associated with the aerobic microbial oxidation of methane, ethane, propane and butane

2007 ◽  
Vol 71 (2) ◽  
pp. 271-283 ◽  
Author(s):  
Franklin S. Kinnaman ◽  
David L. Valentine ◽  
Stanley C. Tyler
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Microbial Oxidation ◽  
Oxidation Of Methane ◽  
Carbon And Hydrogen Isotope

Stable-Isotope Probing Reveals That Hydrogen Isotope Fractionation in Proteins and Lipids in a Microbial Community Are Different and Species-Specific

2013 ◽  
Vol 8 (8) ◽  
pp. 1755-1763 ◽  
Author(s):  
Curt R. Fischer ◽  
Benjamin P. Bowen ◽  
Chongle Pan ◽  
Trent R. Northen ◽  
Jillian F. Banfield
Keyword(s):  
Microbial Community ◽  
Stable Isotope ◽  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Stable Isotope Probing ◽  
Species Specific

Hydrogen Isotope Fractionation in Aqueous Alkali Halide Solutions

1997 ◽  
Vol 52 (11) ◽  
pp. 811-820 ◽  
Author(s):  
Masahisa Kakiuchi
Keyword(s):  
Oxygen Isotope ◽  
Isotope Effect ◽  
Alkali Halide ◽  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Free Water ◽  
Aqueous Alkali ◽  
Water Molecules ◽  
Oxygen Isotope Fractionation ◽  
Hydrogen Isotope Effect

Abstract The D/H ratios of hydrogen gas in equilibrium with aqueous alkali halide solutions were deter-mined at 25 °C, using a hydrophobic platinum catalyst. The hydrogen isotope effect between the solution and pure water changes linearly with the molality of the solution at low concentrations, but deviates from this linearity at higher concentration for all alkali halide solutions. The magnitude of the hydrogen isotope effect is in the order; Kl > Nal > KBr > CsCl ≧ NaBr > KCl > NaCl > LiCl, at concentrations up to a molality of 4 m. The sign and trend of the hydrogen isotope effect is different from that of oxygen. In aqueous alkali halide solutions, the hydrogen isotope effect is influenced by both the cation and the anion species, while the oxygen isotope effect is mainly caused by the cation species. This suggests that the mechanism of hydrogen isotope fractionation between the water molecules in the hydration spheres and the free water molecules differs from the mechanism of the oxygen isotope fractionation. The hydrogen and oxygen isotope effects for alkali halides, except LiCl and NaCl, may be influenced by changes in energy of the hydrogen bonding in free water molecules.

Carbon and hydrogen isotope fractionation of benzene and toluene during hydrophobic sorption in multistep batch experiments

Chemosphere ◽  
2014 ◽  
Vol 107 ◽  
pp. 454-461 ◽  
Author(s):  
G. Imfeld ◽  
F.-D. Kopinke ◽  
A. Fischer ◽  
H.-H. Richnow
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Batch Experiments ◽  
Carbon And Hydrogen Isotope
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