two-dimensional-visualization-quantification-labile-inorganic-plant

Two-Dimensional Visualization and Quantification of Labile, Inorganic Plant Nutrients and Contaminants in Soil

We describe a method for two-dimensional (2D) visualization and quantification of the distribution of labile (i.e., reversibly adsorbed) inorganic ...

Montanuniversität Leoben

This paper presents a combination of elemental and isotopic spatial distribution imaging with near-infrared hyperspectral imaging (NIR-HSI) to evaluate the diagenetic status of skeletal remains. The aim is to assess how areas with biogenic n(Sr)/n(Sr) isotope-amount ratios may be identified in bone material, an important recorder complementary to teeth. Elemental (C, P, Ca, Sr) and isotopic (n(Sr)/n(Sr)) imaging were accomplished via laser ablation (LA) coupled in a split stream to a quadrupole inductively coupled plasma mass spectrometer (ICP-QMS) and a multicollector inductively coupled plasma mass spectrometer (MC ICP-MS) (abbreviation for the combined method LASS ICP-QMS/MC ICP-MS). Biogenic areas on the bone cross section, which remained unaltered by diagenetic processes, were localized using chemical indicators (I(C)/I(Ca) and I(C) × 10/I(P) intensity ratios) and NIR-HSI at a wavelength of 1410 nm to identify preserved collagen. The n(Sr)/n(Sr) isotope signature analyzed in these areas was in agreement with the biogenic bulk signal revealed by solubility profiling used as an independent method for validation. Elevated C intensities in the outer rim of the bone, caused by either precipitated secondary minerals or adsorbed humic materials, could be identified as indication for diagenetic alteration. These areas also show a different n(Sr)/n(Sr) isotopic composition. Therefore, the combination of NIR-HSI and LASS ICP-QMS/MC ICP-MS allows for the determination of preserved biogenic n(Sr)/n(Sr) isotope-amount ratios, if the original biogenic material has not been entirely replaced by diagenetic material. Graphical abstract ᅟ.

A combined chemical imaging approach using (MC) LA-ICP-MS and NIR-HSI to evaluate the diagenetic status of bone material for Sr isotope analysis.

Elemental and isotopic pattern of n(Sr)/n(Sr) and δSr/Sr were used to characterise groundwater and recharge of saline ponds in a clastic aquifer in East Austria. Therefore, shallow, artesian and thermal groundwaters of the investigated aquifer along with rainfall and rivers were analysed using (MC) ICP-MS. The n(Sr)/n(Sr) ratio and elemental pattern changed with aquifer depth as a result of progressing bedrock leaching and dissolution with increasing groundwater residence time. The n(Sr)/n(Sr) ratio of shallow groundwater below saline ponds of 0.71019 ± 0.00044 was significantly different from thermal groundwater of 0.71205 ± 0.00035 (U, k = 2). In contrast to previous theories, this result suggested no recharge of saline ponds by upwelling paleo-seawater. Isotope pattern deconvolution revealed that rainfall accounted to about 60% of the n(Sr)/n(Sr) ratio of shallow groundwater below saline ponds. The δSr/Sr values of groundwater decreased from about 0.25 ‰ in most shallow, to predominantly negative values of about -0.24 ‰ in artesian groundwater. This result indicated leaching and dissolution of weathered minerals. In turn, the δSr/Sr of deep thermal groundwater showed positive values of about 0.12 ‰, which suggested removal of Sr from solution by carbonate precipitation. These results highlight the potential of δSr/Sr signature as an additional geochemical tracer.

Analysis of n(Sr)/n(Sr), δSr/Sr and elemental pattern to characterise groundwater and recharge of saline ponds in a clastic aquifer in East Austria.

Copper-based fungicides have been used for a long time in viticulture and have accumulated in many vineyard soils. In this study, incrementing Cu(OH)-based fungicide application from 0.05 to 5 g Cu kg on two agricultural soils (an acidic sandy loam (L, pH 4.95) and an alkaline silt loam (D, pH 7.45)) resulted in 5 times more mobile Cu in the acidic soil. The most sensitive parameters of alfalfa (Medicago sativa) growing in these soils were the root nodule number, decreasing to 34% and 15% of the control at 0.1 g Cu kg in soil L and at 1.5 g Cu kg in soil D, respectively, as well as the nodule biomass, decreasing to 25% and 27% at 0.5 g Cu kg in soil L and at 1.5 g Cu kg in soil D, respectively. However, the enzymatic N-fixation was not directly affected by Cu in spite of the presence of Cu in the meristem and the zone of effective N-fixation, as illustrated by chemical imaging. The strongly different responses observed in the two tested soils reflect the higher buffering capacity of the alkaline silt loam and showed that Cu mitigation and remediation strategies should especially target vineyards with acidic, sandy soils.

Fungicide application increased copper-bioavailability and impaired nitrogen fixation through reduced root nodule formation on alfalfa.

Trace element concentrations in the rhizosphere were quantified to better understand why soil liming often fails to reduce cadmium (Cd) uptake by plants. Maize seedlings were grown on a soil with natural background levels of Cd and zinc (Zn). Soil liming increased soil pH from 4.9 to 6.5 and lowered the soil solution free ion activities by factor 7 (Cd) and 9 (Zn). In contrast, shoot Cd concentrations were unaffected by liming while shoot Zn concentrations were lowered by factor 1.9. Mapping of labile soil trace elements using diffusive gradients in thin films (DGT) in combination with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) revealed an almost complete depletion of Cd in the rhizosphere in all soil treatments, showing that Cd uptake is controlled by diffusion. The flux of Cd from soil to the DGT, with direct contact between the soil and the binding gel, was unaffected by liming whereas it decreased by factor 3 for Zn, closely mimicking the contrasting effects of liming on Cd and Zn bioavailability. This evidence, combined with additional flux data of freshly spiked Cd and Zn isotopes in soil and with modelling, suggests that the diffusive transport of Cd in unsaturated soil is more strongly controlled by the labile adsorbed metal concentration than by its concentration in solution. This is less the case for Zn because of its inherently slower desorption compared to Cd.

Sub-millimeter distribution of labile trace element fluxes in the rhizosphere explains differential effects of soil liming on cadmium and zinc uptake in maize.

Article	Year
A combined chemical imaging approach using (MC) LA-ICP-MS and NIR-HSI to evaluate the diagenetic status of bone material for Sr isotope analysis. Analytical and bioanalytical chemistry\| PubMed ID: 30511253	2019
Analysis of n(Sr)/n(Sr), δSr/Sr and elemental pattern to characterise groundwater and recharge of saline ponds in a clastic aquifer in East Austria. Isotopes in environmental and health studies\| PubMed ID: 30907135	2019
Fungicide application increased copper-bioavailability and impaired nitrogen fixation through reduced root nodule formation on alfalfa. Ecotoxicology (London, England)\| PubMed ID: 31140046	2019
Sub-millimeter distribution of labile trace element fluxes in the rhizosphere explains differential effects of soil liming on cadmium and zinc uptake in maize. The Science of the total environment\| PubMed ID: 32806385	2020

Thomas Prohaska

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