scholarly journals Rare Earth, Trace Element and Stable Isotope Fractionation of Carbonatites at Kruidfontein, Transvaal

2019 ◽  
Keyword(s):  
Rare Earth ◽  
Stable Isotope ◽  
Trace Element ◽  
Isotope Fractionation ◽  
Stable Isotope Fractionation

Effects of Trace Element Concentration on Enzyme Controlled Stable Isotope Fractionation during Aerobic Biodegradation of Toluene

2006 ◽  
Vol 40 (24) ◽  
pp. 7675-7681 ◽  
Author(s):  
Silvia A. Mancini ◽  
Sarah K. Hirschorn ◽  
Martin Elsner ◽  
Georges Lacrampe-Couloume ◽  
Brent E. Sleep ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Trace Element ◽  
Isotope Fractionation ◽  
Element Concentration ◽  
Trace Element Concentration ◽  
Aerobic Biodegradation ◽  
Stable Isotope Fractionation

Maternal and embryonic trace element concentrations and stable isotope fractionation in the smalleye smooth-hound (Mustelus higmani)

Chemosphere ◽  
2020 ◽  
Vol 257 ◽  
pp. 127183 ◽  
Author(s):  
Juliana de Souza-Araujo ◽  
Ryan Andrades ◽  
Marcelo de Oliveira Lima ◽  
Nigel E. Hussey ◽  
Tommaso Giarrizzo
Keyword(s):  
Stable Isotope ◽  
Trace Element ◽  
Isotope Fractionation ◽  
Element Concentrations ◽  
Stable Isotope Fractionation

scholarly journals Formation mechanisms of macroscopic globules in andesitic glasses from the Izu–Bonin–Mariana forearc (IODP Expedition 352)

2020 ◽  
Vol 176 (1) ◽  
Author(s):  
Raúl O. C. Fonseca ◽  
Lina T. Michely ◽  
Maria Kirchenbaur ◽  
Julie Prytulak ◽  
Jeffrey Ryan ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Trace Element ◽  
Isotope Fractionation ◽  
Experimental Studies ◽  
Trace Element Analysis ◽  
Geochemical Data ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Stable Isotope Fractionation ◽  
Textural Evidence

AbstractThe Izu–Bonin–Mariana volcanic arc is situated at a convergent plate margin where subduction initiation triggered the formation of MORB-like forearc basalts as a result of decompression melting and near-trench spreading. International Ocean Discovery Program (IODP) Expedition 352 recovered samples within the forearc basalt stratigraphy that contained unusual macroscopic globular textures hosted in andesitic glass (Unit 6, Hole 1440B). It is unclear how these andesites, which are unique in a stratigraphic sequence dominated by forearc basalts, and the globular textures therein may have formed. Here, we present detailed textural evidence, major and trace element analysis, as well as B and Sr isotope compositions, to investigate the genesis of these globular andesites. Samples consist of $$\hbox {K}_2\hbox {O}$$ K 2 O -rich basaltic globules set in a glassy groundmass of andesitic composition. Between these two textural domains a likely hydrated interface of devitrified glass occurs, which, based on textural evidence, seems to be genetically linked to the formation of the globules. The andesitic groundmass is Cl rich (ca. $$3000\, \mu \hbox {g/g}$$ 3000 μ g/g ), whereas globules and the interface are Cl poor (ca. $$300\, \mu \hbox {g/g}$$ 300 μ g/g ). Concentrations of fluid-mobile trace elements also appear to be fractionated in that globules and show enrichments in B, K, Rb, Cs, and Tl, but not in Ba and W relative to the andesitic groundmass, whereas the interface shows depletions in the latter, but is enriched in the former. Interestingly, globules and andesitic groundmass have identical Sr isotopic composition within analytical uncertainty ($$^{87}\hbox {Sr}/^{86}\hbox {Sr}$$ 87 Sr / 86 Sr of $$0.70580 \pm 10$$ 0.70580 ± 10 ), indicating that they likely formed from the same source. However, globules show high $$\delta ^{11}$$ δ 11 B (ca. + 7$$\permille$$ ‱ ), whereas their host andesites are isotopically lighter (ca. – 1 $$\permille$$ ‱ ), potentially indicating that whatever process led to their formation either introduced heavier B isotopes to the globules, or induced stable isotope fractionation of B between globules and their groundmass. Based on the bulk of the textural information and geochemical data obtained from these samples, we conclude that these andesites likely formed as a result of the assimilation of shallowly altered oceanic crust (AOC) during forearc basaltic magmatism. Assimilation likely introduced radiogenic Sr, as well as heavier B isotopes to comparatively unradiogenic and low $$\delta ^{11}\hbox {B}$$ δ 11 B forearc basalt parental magmas (average $$^{87}\hbox {Sr}/^{86}\hbox {Sr}$$ 87 Sr / 86 Sr of 0.703284). Moreover, the globular textures are consistent with their formation being the result of fluid-melt immiscibility that was potentially induced by the rapid release of water from assimilated AOC whose escape likely formed the interface. If the globular textures present in these samples are indeed the result of fluid-melt immiscibility, then this process led to significant trace element and stable isotope fractionation. The textures and chemical compositions of the globules highlight the need for future experimental studies aimed at investigating the exsolution process with respect to potential trace element and isotopic fractionation in arc magmas that have perhaps not been previously considered.

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.

Effects of food quality, starvation and life stage on stable isotope fractionation in Collembola

Pedobiologia ◽  
2005 ◽  
Vol 49 (3) ◽  
pp. 229-237 ◽  
Author(s):  
Dominique Haubert ◽  
Reinhard Langel ◽  
Stefan Scheu ◽  
Liliane Ruess
Keyword(s):  
Stable Isotope ◽  
Food Quality ◽  
Isotope Fractionation ◽  
Life Stage ◽  
Stable Isotope Fractionation

Magnesium stable isotope fractionation in marine biogenic calcite and aragonite

2011 ◽  
Vol 75 (19) ◽  
pp. 5797-5818 ◽  
Author(s):  
F. Wombacher ◽  
A. Eisenhauer ◽  
F. Böhm ◽  
N. Gussone ◽  
M. Regenberg ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotope Fractionation ◽  
Stable Isotope Fractionation

Compound-Specific Stable Isotope Fractionation of Pesticides and Pharmaceuticals in a Mesoscale Aquifer Model

2016 ◽  
Vol 50 (11) ◽  
pp. 5729-5739 ◽  
Author(s):  
Heide K. V. Schürner ◽  
Michael P. Maier ◽  
Dominik Eckert ◽  
Ramona Brejcha ◽  
Claudia-Constanze Neumann ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotope Fractionation ◽  
Stable Isotope Fractionation
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