Copper isotope fractionation by desert shrubs

Urbina, Jesica; Viveros, Marian N.; Ellzey, Joanne T.; Borrok, David M.

doi:10.1016/j.apgeochem.2011.04.002

Cited by 23 publications

(6 citation statements)

References 13 publications

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“…histidine) in the extracellular medium (in this case, digested food) can have drastic effects on the uptake of copper at the apical membrane 38 and absorption competition can take place among the transition metals in Caco-2 cells. 39 In addition, there is evidence that uptake of copper by bacteria can fractionate isotopes, 40 and therefore differences in gut biota in individual mice, and more so between mice from different studies, could play a role in the difference observed. The copper isotopic composition of the food is an important factor, but not the only factor in determining the isotopic composition of the copper absorbed into the body and further detailed studies are warranted to understand these effects.…”

Section: Resultsmentioning

confidence: 99%

“…An important consideration when measuring copper isotopic composition in biological materials is the high sodium content, which must be effectively removed to prevent a possible isobaric interference from 40 Ar 23 Na + on the 63 Cu signal. To assess the level of sodium required to have a measurable effect on the copper isotopic composition we prepared solutions containing 100 ng of copper with varying levels of sodium (0 to 500 ng) in 1.0 mL of 3% HNO 3 .…”

Section: Copper Stable Isotope Analysismentioning

confidence: 99%

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The expression levels of cellular prion protein affect copper isotopic shifts in the organs of mice

Miller

Keenan

Martin

et al. 2016

J. Anal. At. Spectrom.

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Section: Resultsmentioning

confidence: 99%

Section: Copper Stable Isotope Analysismentioning

confidence: 99%

The expression levels of cellular prion protein affect copper isotopic shifts in the organs of mice

Miller

Keenan

Martin

et al. 2016

J. Anal. At. Spectrom.

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“…The Cu isotopic compositions of the mineral A and B horizons may be influenced by plant uptake, which could explain the observed tendency towards heavier d 65 Cu values. Indeed, most published data indicate preferential incorporation of light Cu in plant roots during uptake from soil (e.g., Navarrete et al, 2011;Weinstein et al, 2011). In contrast, polluted soils have O horizons enriched in heavy Cu with a positive d 65 Cu (ANOVA using the Fischer test at 95 % confidence level, Table 2).…”

Section: Copper and Zinc Isotopic Fractionation During Pedogenesismentioning

confidence: 99%

Tracing contamination sources in soils with Cu and Zn isotopic ratios

Fekiacova

Cornu

Pichat

2015

Science of The Total Environment

106

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Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are important micronutrients. Human activities contribute to the input of these metals to soils in different chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution. The aim of this paper is to determine whether it is possible to identify (i) Cu and Zn contamination in soils and their sources, on the basis of their isotopic signatures, and (ii) situations that are a priori favorable or not for tracing Cu and Zn pollution using the isotopic approach. Therefore, we compiled data from the literature on Cu and Zn isotopes in soils, rocks and pollutants and added to this database the results of our own research. As only a few studies have dealt with agricultural contamination, we also studied a soil toposequence from Brittany, France, that experienced spreading of pig slurry for tens of years. In the surface horizons of the natural soils, the δ(65)Cu values vary from -0.15 to 0.44‰ and the δ(66)Zn from -0.03 to 0.43‰. Furthermore, vertical variations along soil profiles range from -0.95 to 0.44‰ for δ(65)Cu and from -0.53 to 0.64‰ for δ(66)Zn values. We concluded that pedogenetic processes can produce isotopic fractionation, yet, it is not always discernible and can be overprinted by an exogenous isotopic signature. Furthermore, some contaminants are enriched in heavy Cu or in light Zn compared to the rock or soil, but no generalization can be made. The anthropogenic inputs can be identified based on stable Cu and Zn isotope ratios if the isotope ratios of the sources are different from those of the soil, which needs to be tested for each individual case.

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“…As only 8–10% of Cu was adsorbed to the biofilm surface functional groups (data obtained from 5 min EDTA wash), the Δ( 65 Cu incorporated‑solution ) could be extrapolated to 0 (between +0.04 and 0.00‰) for an isotopic signature of the adsorbed Cu equal to +1.1‰ . In previous studies, the adsorption onto the micro-organism surface or biofilm generally induced an enrichment in heavy isotopes, , whereas intracellular assimilation of Cu favored light isotopes. ,− Therefore, we suggest that the daytime Cu isotope fractionation between the biofilm and aqueous solution was essentially regulated by Cu complexation to functional groups within the EPS matrix under a subordinate role of metabolic intracellular uptake. This 3-D sorption (incorporation) of Cu could occur essentially via high-affinity binding sites predominating at low concentration, which favored the incorporation of heavy isotopes, also consistent with mechanisms of Cu fractionation in plants …”

Section: Discussionmentioning

confidence: 64%

Elemental and Isotopic Variations of Copper and Zinc Associated with the Diel Activity of Phototrophic Biofilm

Coutaud

Paule

Méheut

et al. 2020

Environ. Sci. Technol.

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The response in metal concentrations and isotopic composition to variations in photosynthetic activity of aquatic micro-organisms is crucially important for understanding the environmental controls on metal fluxes and isotope excursions. Here we studied the impacts of two successive diel cycles on physicochemical parameters, Cu and Zn concentrations, and isotopic composition in solution in the presence of mature phototrophic biofilm in a rotating annular bioreactor. The diel cycles induced fluctuations in temperature, pH, and dissolved oxygen concentration following the variation in the photosynthesis activity of the biofilm. Diel variations in metal concentrations were primarily related to the pH variation, with an increase in metal concentration in solution related to a pH decrease. For both metals, δ( 66 Zn) and δ( 65 Cu) in solution exhibited complex but reproducible diel cycles. Diel variations in photosynthetic activity led to alternatively positive and negative isotope fractionation, producing the sorption of light Zn (Δ( 66 Zn sorbed-solution ) = −0.1 ± 0.06‰) and heavy Cu isotopes (Δ( 65 Cu sorbed-solution ) = +0.17 ± 0.06‰) during the day at high pH and the excretion of lighter Zn isotopes (−0.4‰ < Δ( 66 Zn excreted-biofilm ) < +0.14‰) and heavy Cu isotopes (Δ( 65 Cu excreted-biofilm ) = +0.7 ± 0.3‰) during the night at lower pH. We interpreted Zn and Cu diel cycles as a combination of a desorption of exopolymeric substance−metal complexes and a small active efflux during the night with adsorption and incorporation via an active uptake during the day. The hysteresis of metal concentration in solution over the diel cycle suggested the more important role of uptake compared to desorption and efflux from the biofilm. The phototrophic biofilm presents a non-negligible highly labile metal pool with important potential for contrasting isotopic fractionation at the diel scale.

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Copper isotope fractionation by desert shrubs

Cited by 23 publications

References 13 publications

The expression levels of cellular prion protein affect copper isotopic shifts in the organs of mice

The expression levels of cellular prion protein affect copper isotopic shifts in the organs of mice

Tracing contamination sources in soils with Cu and Zn isotopic ratios

Elemental and Isotopic Variations of Copper and Zinc Associated with the Diel Activity of Phototrophic Biofilm

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