scholarly journals Biological effects on uranium isotope fractionation (238U/235U) in primary biogenic carbonates

2018 ◽  
Vol 240 ◽  
pp. 1-10 ◽  
Author(s):  
Xinming Chen ◽  
Stephen J. Romaniello ◽  
Achim D. Herrmann ◽  
Elias Samankassou ◽  
Ariel D. Anbar
Keyword(s):  
Isotope Fractionation ◽  
Biological Effects ◽  
Uranium Isotope ◽  
Biogenic Carbonates

Uranium Isotope Fractionation during the Anoxic Mobilization of Noncrystalline U(IV) by Ligand Complexation

2021 ◽  
Author(s):  
Yvonne Roebbert ◽  
Chris Daniel Rosendahl ◽  
Ashley Brown ◽  
Axel Schippers ◽  
Rizlan Bernier-Latmani ◽  
...  
Keyword(s):  
Isotope Fractionation ◽  
Uranium Isotope

No ion is an island: Multiple ions involved during boron incorporation into CaCO3

2021 ◽  
Author(s):  
Michael Henehan ◽  
Christa Klein-Gebbinck ◽  
Gavin Foster ◽  
Jill Wyman ◽  
Mathis Hain ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Isotope Fractionation ◽  
Isotope Composition ◽  
Boron Isotope ◽  
Minor Role ◽  
Growth Mechanisms ◽  
Minor Elements ◽  
Vital Effects ◽  
Biogenic Carbonates ◽  
Trace And Minor Elements

<p>Boron isotope ratios, as measured in marine calcium carbonate, are a proven tracer of past seawater and calcifying fluid pH and thus a powerful tool for the reconstruction of past atmospheric CO<sub>2</sub> and monitoring of coral physiology. For such applications, understanding the inorganic baseline upon which foraminiferal vital effects or coral pH upregulation are superimposed should be an important prerequisite. Yet, investigations into boron isotope fractionation in synthetic CaCO<sub>3 </sub>polymorphs have often reported variable and even conflicting results, implying that we may not fully understand pathways of boron incorporation into calcium carbonate.  Here we address this topic with experimental data from calcite and aragonite precipitated across a range of pH in the presence of both Mg and Ca. We confirm the results of previous studies that the boron isotope composition of inorganic aragonite precipitates closely reflects that of aqueous borate ion, but that calcites display a higher degree of scatter, and diverge from the boron isotope composition of borate ion at low pH. We discuss these findings with reference to the simultaneous incorporation of other trace and minor elements, and highlight a number of mechanisms by which crystal growth mechanisms may influence the concentration and isotope composition of boron in CaCO<sub>3</sub>. In particular, we highlight the potential importance of surface electrostatics in driving variability in published synthetic carbonate datasets. Importantly for palaeo-reconstruction, however, these electrostatic effects are likely to play a much more minor role during natural precipitation of biogenic carbonates.</p>

scholarly journals Identifying vital effects in <i>Halimeda</i> algae with Ca isotopes

2014 ◽  
Vol 11 (24) ◽  
pp. 7207-7217 ◽  
Author(s):  
C. L. Blättler ◽  
S. M. Stanley ◽  
G. M. Henderson ◽  
H. C. Jenkyns
Keyword(s):  
Isotope Fractionation ◽  
Isotope Composition ◽  
Test Organism ◽  
Isotope Ratios ◽  
First Order ◽  
Geological Past ◽  
Rayleigh Distillation ◽  
Vital Effects ◽  
Specific Factors ◽  
Biogenic Carbonates

Abstract. Geochemical records of biogenic carbonates provide some of the most valuable records of the geological past, but are often difficult to interpret without a mechanistic understanding of growth processes. In this experimental study, Halimeda algae are used as a test organism to untangle some of the specific factors that influence their skeletal composition, in particular their Ca-isotope composition. Algae were stimulated to precipitate both calcite and aragonite by growth in artificial Cretaceous seawater, resulting in experimental samples with somewhat malformed skeletons. The Ca-isotope fractionation of the algal calcite (−0.6‰) appears to be much smaller than that for the algal aragonite (−1.4‰), similar to the behaviour observed in inorganic precipitates. However, the carbonate from Halimeda has higher Ca-isotope ratios than inorganic forms by approximately 0.25‰, likely because of Rayleigh distillation within the algal intercellular space. In identifying specific vital effects and the magnitude of their influence on Ca-isotope ratios, this study suggests that mineralogy has a first-order control on the marine Ca-isotope cycle.

scholarly journals Aqueous Chemistry Influences Uranium Isotope Fractionation

2020 ◽  
Author(s):  
Noah Jemison ◽  
Hakim Boukhalfa ◽  
Ricardo Marti-Arbona ◽  
Chris Yeager ◽  
Robert Williams ◽  
...  
Keyword(s):  
Isotope Fractionation ◽  
Uranium Isotope ◽  
Aqueous Chemistry

scholarly journals Identifying vital effects in <i>Halimeda</i> algae with Ca isotopes

2014 ◽  
Vol 11 (3) ◽  
pp. 3559-3580 ◽  
Author(s):  
C. L. Blättler ◽  
S. M. Stanley ◽  
G. M. Henderson ◽  
H. C. Jenkyns
Keyword(s):  
Intercellular Space ◽  
Isotope Fractionation ◽  
Isotope Composition ◽  
Test Organism ◽  
First Order ◽  
Geological Past ◽  
Rayleigh Distillation ◽  
Vital Effects ◽  
Specific Factors ◽  
Biogenic Carbonates

Abstract. Geochemical records of biogenic carbonates provide some of the most valuable records of the geological past, but are often difficult to interpret without a mechanistic understanding of growth processes. In this experimental study, Halimeda algae are used as a test organism to untangle some of the specific factors that influence their skeletal composition, in particular their Ca-isotope composition. Algae were stimulated to precipitate both calcite and aragonite by growth in artificial Cretaceous seawater. The Ca-isotope fractionation of the algal calcite is much smaller than that for the algal aragonite, similar to the behaviour observed in inorganic precipitates. However, the carbonate from Halimeda is isotopically heavier than inorganic forms, likely due to Rayleigh distillation within the algal intercellular space. In identifying specific vital effects and the magnitude of their influence on Ca-isotope ratios, this study suggests that mineralogy has a first-order control on the Ca-isotope budget of the carbonate sink and the Ca-isotope composition of seawater.

Uranium Isotope Fractionation during Adsorption, (Co)precipitation, and Biotic Reduction

2016 ◽  
Vol 50 (23) ◽  
pp. 12695-12704 ◽  
Author(s):  
Duc Huy Dang ◽  
Breda Novotnik ◽  
Wei Wang ◽  
R. Bastian Georg ◽  
R. Douglas Evans
Keyword(s):  
Isotope Fractionation ◽  
Uranium Isotope ◽  
Co Precipitation

scholarly journals Uranium isotope fractionation during coprecipitation with aragonite and calcite

2016 ◽  
Vol 188 ◽  
pp. 189-207 ◽  
Author(s):  
Xinming Chen ◽  
Stephen J. Romaniello ◽  
Achim D. Herrmann ◽  
Laura E. Wasylenki ◽  
Ariel D. Anbar
Keyword(s):  
Isotope Fractionation ◽  
Uranium Isotope

scholarly journals Uranium isotope fractionation during slab dehydration beneath the Izu arc

2019 ◽  
Vol 522 ◽  
pp. 244-254 ◽  
Author(s):  
Heye Freymuth ◽  
Morten B. Andersen ◽  
Tim Elliott
Keyword(s):  
Isotope Fractionation ◽  
Uranium Isotope ◽  
Slab Dehydration

scholarly journals Possible Mechanisms of Biological Effects Observed in Living Systems during 2H/1H Isotope Fractionation and Deuterium Interactions with Other Biogenic Isotopes

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4101 ◽  
Author(s):  
Alexander Basov ◽  
Liliya Fedulova ◽  
Ekaterina Vasilevskaya ◽  
Stepan Dzhimak
Keyword(s):  
Metabolic Pathways ◽  
Intercellular Space ◽  
Isotope Fractionation ◽  
Biological Effects ◽  
Experimental Studies ◽  
Living Systems ◽  
Chemical Bonds ◽  
Molecular Effects ◽  
Tunnel Effects ◽  
New Hypothesis

This article presents the original descriptions of some recent physics mechanisms (based on the thermodynamic, kinetic, and quantum tunnel effects) providing stable 2H/1H isotope fractionation, leading to the accumulation of particular isotopic forms in intra- or intercellular space, including the molecular effects of deuterium interaction with 18O/17O/16O, 15N/14N, 13C/12C, and other stable biogenic isotopes. These effects were observed mainly at the organelle (mitochondria) and cell levels. A new hypothesis for heavy nonradioactive isotope fractionation in living systems via neutron effect realization is discussed. The comparative analysis of some experimental studies results revealed the following observation: “Isotopic shock” is highly probable and is observed mostly when chemical bonds form between atoms with a summary odd number of neutrons (i.e., bonds with a non-compensated neutron, which correspond to the following equation: Nn − Np = 2k + 1, where k ϵ Z, k is the integer, Z is the set of non-negative integers, Nn is number of neutrons, and Np is number of protons of each individual atom, or in pair of isotopes with a chemical bond). Data on the efficacy and metabolic pathways of the therapy also considered 2H-modified drinking and diet for some diseases, such as Alzheimer’s disease, Friedreich’s ataxia, mitochondrial disorders, diabetes, cerebral hypoxia, Parkinson’s disease, and brain cancer.

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