ACS Publications. Most Trusted. Most Cited. Most Read
Quick View

OR SEARCH CITATIONS

My Activity
Publications
CONTENT TYPES

Figure 1Loading Img
Download Hi-Res ImageDownload to MS-PowerPointCite This:Anal. Chem. 2019, 91, 9, 6225-6232
RETURN TO ISSUEPREVArticleNEXT

Spatial Microanalysis of Natural 13C/12C Abundance in Environmental Samples Using Laser Ablation-Isotope Ratio Mass Spectrometry

  • Andrei Rodionov*
    Andrei Rodionov
    Institute of Crop Science and Resource Conservation (INRES), Soil Science and Soil Ecology, University of Bonn, Nussallee 13, Bonn 53115, Germany
    *E-mail: [email protected]
    More by Andrei Rodionov
    Orcidhttp://orcid.org/0000-0001-5971-1948
  • , 
  • Eva Lehndorff
    Eva Lehndorff
    Soil Ecology, University of Bayreuth, Dr.-Hans-Frisch-Str. 1-3, Bayreuth 95448, Germany
    More by Eva Lehndorff
  • , 
  • Ciprian C. Stremtan
    Ciprian C. Stremtan
    Teledyne CETAC Technologies, 14306 Industrial Road, Omaha, Nebraska 68144, United States
    More by Ciprian C. Stremtan
  • , 
  • Willi A. Brand
    Willi A. Brand
    Max-Planck-Institute for Biogeochemistry, Beutenberg Campus, P.O. Box 100164, Jena 07701, Germany
    More by Willi A. Brand
  • , 
  • Heinz-Peter Königshoven
    Heinz-Peter Königshoven
    Feinmechanische Werkstatt, Institute of Physical and Theoretical Chemistry, University of Bonn, Wegeler Str. 12, Bonn 53115, Germany
    More by Heinz-Peter Königshoven
  • , and 
  • Wulf Amelung
    Wulf Amelung
    Institute of Crop Science and Resource Conservation (INRES), Soil Science and Soil Ecology, University of Bonn, Nussallee 13, Bonn 53115, Germany
    More by Wulf Amelung
Cite this: Anal. Chem. 2019, 91, 9, 6225–6232
Publication Date (Web):April 1, 2019
https://doi.org/10.1021/acs.analchem.9b00892

Copyright © 2019 American Chemical Society. This publication is licensed under these Terms of Use.

Request reuse permissions
  • Open Access

Article Views

2113

Altmetric

-

Citations

22
LEARN ABOUT THESE METRICS
PDF (5 MB)
Get e-Alerts
Supporting Info (1)»
SUBJECTS:

Abstract

High Resolution Image
Download MS PowerPoint Slide

The stable 13C/12C isotope composition usually varies among different organic materials due to isotope fractionation during biochemical synthesis and degradation processes. Here, we introduce a novel laser ablation-isotope ratio mass spectrometry (LA-IRMS) methodology that allows highly resolved spatial analysis of carbon isotope signatures in solid samples down to a spatial resolution of 10 μm. The presented instrumental setup includes in-house-designed exchangeable ablation cells (3.8 and 0.4 mL, respectively) and an improved sample gas transfer, which allow accurate δ13C measurements of an acryl plate standard down to 0.6 and 0.4 ng of ablated carbon, respectively (standard deviation 0.25‰). Initial testing on plant and soil samples confirmed that microheterogeneity of their natural 13C/12C abundance can now be mapped at a spatial resolution down to 10 μm. The respective δ13C values in soils with C3/C4 crop sequence history varied by up to 14‰ across a distance of less than 100 μm in soil aggregates, while being partly sorted along rhizosphere gradients of <300 μm from Miscanthus plant roots into the surrounding soil. These very first demonstrations point to the appearance of very small metabolic hotspots originating from different natural isotope discrimination processes, now traceable via LA-IRMS.

The stable 13C/12C isotope composition of environmental samples has become a unique tracer of carbon assimilation pathways. In plants, its analysis provided key information about the assimilation of fossil carbon sources (Suess effect) (1) and about differentiated C3 and C4 photosynthetic pathways (2,3) and gave hints regarding water stress adaptation pathways. (4−6) In marine and lacustrine environments, the analysis helped to track terrestrial C input and was useful for paleoclimate reconstruction. (7−9) In terrestrial environments, δ13C analyses were indispensable for assessing the mean residence time of soil carbon after C3/C4 vegetation changes, (10,11) for elucidating microbial and faunal food webs, (12) and for paleo-environmental reconstructions. (13−16) However, spatially homogeneous C isotope signals were assumed for all these studies because it has not been possible to map microscale variation of the 13C/12C isotope composition in routine lab analyses down to the natural abundance level. The present contribution provides a viable solution to this problem.
Different instrumental setups using laser ablation (LA) combined with other detectors have already been applied on a micrometer scale for measuring bacterial cells and plant and animal tissue, as well as to other substances in geological and biological studies. (17−23) For ablation of organic matter, cold Nd:YAG laser ablation systems are recommended. (24,25) Lasers operating at 213 nm ensure cold ablation as more traditional 266 nm systems (24,25) and thus avoid isotope fractionation effects during the ablation process. All previous laser ablation studies relied on obtaining spatially resolved signatures from organic solids with relatively large and homogeneous organic C contents compared to soil (wood, single hair samples, or pollen grains of C3 and C4 plants), yielding ablation spot sizes between 150 and 50 μm (22,24,25) and a sensitivity between 65 and 24 ng C. (25,26) Higher spatial resolution and sensitivity are crucial for many environmental studies, which have aims such as identifying microbial hotspots in soils and sediments, or patchy sequestration of carbon.
In this contribution, we introduce a laser ablation-isotope ratio mass spectrometry (LA-IRMS) system using a frequency quintupled 213 nm Q-switched Nd:YAG laser with <5 ns pulse width and flat-top energy profile (>4 mJ pulse–1; Teledyne CETAC Technologies, Omaha, USA). Laser ablation of particulate matter was done in newly designed low-volume cells; the ablated particles were collected and transported using helium as the carrier gas. Particles were oxidized to CO2 in an oven; then, sample gas was transferred to a system of two cryo-traps for gas cleanup and peak focus (modified PreCon system; see ref (27)). Sample gas was then led through a GC column before it entered the IRMS DeltaVplus via a ConFloIV interface (both from ThermoFisher Scientific) for analysis of δ13C. The challenges were to increase the spatial resolution of the δ13C signal by an order of magnitude by decreasing the area of ablated spots down to 10 μm, thus responding to a growing interest in isotopical characterization of microbial hot spots, organic exudates of roots, and residues of plants and microbes. Doing so would enable us to reach into areas where the utilization of organic materials is physically hindered by, e.g., encrustation processes and occlusion within aggregates and, thus, limited bioaccessibility.

Experimental Approach

ARTICLE SECTIONS
Jump To

Ablation System and Isotope Measurement

For laser ablation, highly focused laser light pulses are used to remove (ablate) material at a spatial resolution of a few micrometers in diameter from discrete areas of virtually any solid sample (e.g., ref (28) and references therein). For the present study, we used a Teledyne LSX-213G2+ solid state Nd:YAG laser system (CETAC, Omaha, NE, USA) that produces deep UV laser radiation at a wavelength of 213 nm. The laser pulse frequency can be variably adjusted; frequencies from 10 to 20 Hz proved to be optimal for this application. Furthermore, the laser allowed adjustment of the energy output, the ablated spot size, and the number of laser shots.
The standard cell of the LSX213 G2+ laser (two volume active cell HelEx II) was replaced with an in-house-designed single-volume cell (see Figure 1; the cell was constructed with an active volume of 3.8 cm3 and a total internal volume of 17.2 cm3; for details see Figure S-1). The cell was mounted on an adapted plane mount aligned to the laser’s original movable stages, which allowed the sample to be monitored by a computer-controlled video microscope and internal LED illumination (coaxial, ring, and transmitted light sources). As we expected, the samples to have very low amounts of C, we also produced a second cell with the same design, but with an even smaller active volume of 0.4 cm3 and, therefore, with reduced background signal. Both cells are easy to handle and are interchangeable.

Figure 1

Figure 1. Setup of the LA-IRMS system starting with a newly constructed low-volume cell. Only the upper part of the cell is the active operating volume for laser ablation (marked in red; more details in the Supporting Information).

High Resolution Image
Download MS PowerPoint Slide
The upper and lower windows of the single-volume cell were made of quartz glass and sealed using O-rings (Ø30 × 2 mm; form error: 3/0.5 wedge: <5′; Laseroptik corp., Garbsen, Germany). The top window was specially coated (AR213 nm/0°; R < 0.25%) to reduce reflection of the 213 nm wavelength.
The system was continuously flushed with high purity helium (BIP5.0), which ran through a stainless steel line of 1/16 in., directly connected to a mass flow controller (MFC adjusted to constant flow rate of 10 mL min–1; Alicat, Cole-Palmer, Vernon-Hills, IL, USA) and a PEEK 1/16 in. line between the MFC and the cell (Figure 1).
The resin-embedded sample was positioned on a spring inside the cell to reduce the cell’s active volume (see Figure S-1; sample was embedded in Araldite 2020, Huntsman, δ13C −29.98 ± 0.5‰, and then cut and polished with corundum to avoid C contamination on the sample surface). Helium was purged with 10 mL/min into the passive volume of the cell and then directed via four channels to the active cell volume above the sample. These four channel outlets were tilted (with 45° to the cell radius) to ensure gas rotation on the sample surface, thus increasing flow dynamics and particle suspension in the gas phase. The maximum sample diameters were 25 and 10 mm (3.8 and 0.4 cm3 cell volume), respectively, which corresponds to sample sizes used in other applications, such as nanoscale secondary ion mass spectrometry (NanoSIMS).
The output port was laterally aligned close to the sample surface to increase particle collection efficiency (Figure S-1). This port was coupled to an IRMS via a PreCon automated interface, equipped with a continuous gas flow combustion furnace. The furnace was used to convert the carbon in the ablated sample to CO2 at 900 °C. Low cell volumes allowed the oxidation of the complete sample in the oven. A Nafion trap was installed after the furnace to eliminate remaining traces of water. This was followed by cryo-trapping of the evolved CO2 in a first automated trap using liquid nitrogen (Figure 1). The second automated trap focused the CO2. After switching the Valco valve, both traps were purged with a reduced He flow, now received from the ConFlo interface (He flow of approximately 0.3 mL min–1). Sample gas was then led through a capillary column for further cleanup and peak shaping (PoraPLOT Q, 25 m length, 0.25 mm diameter, 8 μm film; Agilent Technologies, Santa Clara, CA, USA) to a ConFlow and Delta V plus IRMS detector (Figure 1; ThermoFisher Scientific, Bremen, Germany). During sample exchange and stand-by, an additional He flow was added through the PreCon system (He purge at 10 psi, Figure 1) to ensure continuous He flow through the combustion furnace and lines (for stand-by, helium flow from the laser MFC had to be reduced to 3 mL min–1 to avoid overpressure at the laser (max. 19 psi)). To maintain the oxidizing capacity of the combustion, the furnace was periodically oxidized by using a Crystal-mix (Helium N46 mixed with 5.0 ± 0.1 Vol% Oxygen N45).
For accurate isotope ratio assessment, we used the Isodat Software (ThermoFisher Scientific), which basically starts each run with a peak center adjustment. Then, three peaks of CO2 reference gas were introduced before sample ablation started. Directly before sample gas analysis, the IRMS performance was again checked by two CO2 reference peaks (reference gas switched in through ConFloIV after cryo-trapping). The complete analytical procedure was programmed via an ISL protocol embedded in the Isodat software, which enables timing of valve position change, ConFloIV action (CO2 reference gas inlet/sample gas inlet), and positioning of cryo-traps. The laser was controlled via the Chromium2.2 software (Laser Ablation System V.2017.1.31.0), and the ablation was started manually to work in time with the IRMS part of the LA-IRMS system. Each sample run needed about 10 min.

Standards and Reference Samples

For calibration of the CO2 gas tank and reference samples, we used isotope reference standards reported versus Vienna PeeDee Belemnite (vs VPDB; acetanilide −29.53‰; cellulose −24.72‰; sucrose −10.45‰; National Institute of Standards and Technology, Gaithersburg, MD, USA), measured on a FlashEA 1112 elemental analyzer connected to a Delta V advantage IRMS (ThermoFisher Scientific, Bremen, Germany). In-house EA-IRMS referenced samples, which were chosen to resemble different types of organic matter occurring in soil, were applied to test the LA-IRMS system (beech wood −27.09 ± 0.02‰; einkorn wheat −28.71 ± 0.03‰; acryl plate −29.75 ± 0.06‰; IAEA-CH-3–24.77 ± 0.06‰; sucrose −26.93 ± 0.05‰; Gordonia alcanivorans −23.07 ± 0.00‰).
For the ablation tests, we produced press-pellets from each separate and in-house-referenced sample. With the exception of the IAEA-CH-3 standard (29) (which was cut into pieces), all samples were thoroughly homogenized to avoid any inconsistencies. The standards were placed in stainless steel sample holders in order to avoid any cross contamination (Figure S2). Each sample was ablated several times to test the effects of laser energy efficiency, as well as to try and correlate ablation depth to the number of shots.

Environmental Samples

To illustrate the performance of our LA-IRMS system, we used the following sample sets: (1) We assessed the carbon isotope composition in so-called occluded large microaggregates (53–250 μm), isolated from wet fractionated and ultrasonically treated macroaggregates (250–8000 μm). Such aggregates are considered to play a key role in C sequestration processes in soil because they protect physically occluded C from decay. (2) We assessed the carbon isotope signature along gradients from C4 roots (Miscanthus) into the surrounding soil (previously under C3 vegetation), with the knowledge that the living area around roots (the so-called rhizosphere) is a hot spot for microbial activity, thus inducing steep gradients in carbon concentration and its turnover. (3) We assessed the spatial variability of carbon isotope composition in soil particles <2 mm, which have received C inputs by C3 and C4 vegetation (two years after C3 to C4 vegetation change).
Soil microaggregates (set 1) were formed in arable loamy Haplic Luvisols (35% clay; 5–15 cm sampling depth, Scheyern experiment station, Southern Germany). (30)
Topsoil samples from a Miscanthus field (set 2) were collected from the experimental research station of Bonn University in Klein-Altendorf, Germany, continuously cropped with Miscanthus since 2007. Coordinates were 50°35′37.18 N/6°59′10.24 E at an altitude of 240 m a.s.l. The mean annual temperature and precipitation were 9.5 °C and 605 mm. The main soil type was a Luvic Stagnosol (Episiltic) (IUSS Working Group WRB, 2015), with a silty-loam texture (63% silt, 23% clay, and 14% sand). (31)
For set 3, soil particles <2 mm from a C3/C4 vegetation change experiment at the Terrestrial Observatory TERENO, Selhausen, Germany, were sampled in 2014 (0–30 cm soil depth). Soil had been continuously cropped with maize since 2012 (Zea mays L.). (32) The mean annual temperature and precipitation were 9.8 °C and 693 mm, respectively. The main soil type was a Stagnic Cambisol (Skeletic) (IUSS Working Group WRB, 2015) with a silty-loam texture (64% silt, 15% clay, and 18% sand). (32)
Environmental samples were taken as large blocks with a spade. They were manually broken to undisturbed aggregates of approximately 15 mm in diameter and air-dried (set 2), further processed using wet sieving into different aggregate size classes and freeze-dried (set 1), (30) or simply dry-sieved to 2 mm (set 3). (32) The dried subsamples were then embedded in Araldite before analysis.

Surface Mapping

To determine the ablation quality and to assess the crater depth and amount of ablated material, noncontact 2D and 3D surface mappings were applied to the acryl plate in-house standard. The measurements were carried out using an Omniscan MicroXAM white lite roughness microstitching interferometer (ADE Phase Shift, Tucson, AZ, USA) at Trinity College Dublin Center for Microscopy and Analysis. The repeated measurements of the crater depths were performed on combinations of ablation spot size with number of shots (Figure S3; Table S1; n = 5).

Results and Discussion

ARTICLE SECTIONS
Jump To

Blank Minimizing through Sample Aerosol Transport Optimization

There is a general risk that CO2 from sources other than the sample may contribute to the assessment of δ13C values by LA-IRMS. We call this the blank signal, originating from small amounts of CO2 already present in the cell, entering through the Valco-6-port connector, or resulting from other tiny leakages in the system. Thus, the isotope discrimination tests were performed at C concentrations far above the blank signal. However, to perform accurate LA-IRMS analyses at very low C concentrations at high spatial resolution, minimization of the blank signal was crucial. We observed that its contribution to the total signal increased with increasing loading time on the cryo-trap (Figure 2). However, the isotope composition of the blank was not affected by the loading time. It averaged −18.78 ± 0.54‰, ranging from −17.93‰ to −19.27‰ on different days (n = 34; individual data not shown). With the 3.8 mL cell and a trap loading time of 7 s, the blank fell below the routine detection limit of the IRMS system (which was preset to 50 mV; that is, close to the baseline). With a loading time of 20 s, the blank signal remained stable with a peak area less than 0.6 Vs; this means that any signal above this value must have resulted from sample ablation. Thus, very clear ablation signals from the in-house acryl standard were produced with spots of 30 μm size and 40 shots in a 3.8 mL cell volume (Figure S-4). By minimizing the time window for cryo-trapping, that is, finding the optimum delay time between particle ablation in the cell and particle arrival at trap 1 (loading time), the blank signal could be reduced significantly as needed for improved sensitivity. All these steps were controlled by the Valco-6-port valve in the PreCon settings (modified ISL method of the PreCon, loaded in the Isodat Software, ThermoFisher Scientific). The method was programmed with a delay time of 2 s until switching to cryo-trapping with a loading time of 20 s for the 3.8 mL cell (see details for the 0.4 mL cell below).

Figure 2

Figure 2. Impact of loading time in the first cryo-trap on the blank peak area in cells with 3.8 and 0.4 mL active volume (without laser ablation). If the loading time was <7 s, the blank was at the baseline level of the IRMS detector for both cells. The isotopic signature of the blank signal was not affected by the loading time.

High Resolution Image
Download MS PowerPoint Slide

Energy Efficiency and Limitation of the Fractionation

First, we tested the optimal efficiency of the LA-IRMS system under different ablation settings and for different in-house standardized organic materials with known δ13C value, such as beech wood, sucrose, einkorn grass, the actinomycete Gordonia alcanivorans, an acryl plate, and the certified IAEA-CH-3 standard. The question was whether these organic materials, which commonly occur in soil, show different ablation behavior. To perform these tests, we produced press-pellets from milled standard materials and placed them in the metal sample holders (Figure S-1a,b). According to Jeong et al., (33) the entrainment efficiency of particle transport decreases with increasing laser power density and is strongly affected by laser beam diameter at constant laser pulse energy (that is, removing more sample than can be efficiently collected and transported) or at variable laser pulse energy with fixed spot size. We tested the appropriate laser pulse energy using a fixed spot size and a fixed number of shots in increments, starting from the configuration of 40% energy output to 20%, 15%, 10%, 5%, and finally 3.5% energy output (Figure 3). Using a constant spot size of 30 μm and 40 pulses, the results of different in-house-referenced samples clearly showed that the 3.5% energy output setting of the laser (corresponding to a fluence of 0.71 J/cm2) was appropriate for organic matter ablation independent of matrix. If higher laser energies were set, δ13C decreased from the referenced value, probably due to partial heating of the sample inducing isotopic discrimination (Figure 3). Also, the blank contribution was significantly reduced and, since this was constant during the day, it did not interfere with the sample measurements. Across different days, however, the isotope composition of the blank varied, which must be accounted for when analyzing a sample at different days (Figure 3).

Figure 3

Figure 3. Discrimination of stable carbon isotopes from different organic matrices by ablation with increasing laser energy.

High Resolution Image
Download MS PowerPoint Slide

Sensitivity

The sensitivity of the LA-IRMS system was tested by applying variable spot sizes (40, 30, 25, 20, 15, and 10 μm) and numbers of pulses (40, 30, 20, and 10 shots) to our organic matrices (cell size 3.8 mL, Figure S-4a,b). As expected, the results showed that decreasing the spot size impacted the resulting signal intensity more than a decreasing number of shots. The combination of both, that is, the dilution of the blank signal in a sample by increasing the sample volume, resulted in a linear decrease of the measured isotope signal for all tested in-house-referenced samples (Δδ13C = δ13Ctotal – δ13Creference; Figure S-4a; Table S1). In the 3.8 mL cell, the isotope signal was stable for 30 μm spots due to a negligible blank signal, and the resulting isotope signatures were close to the reference values (Figure S-4b).
Here, we directly measured the blank value and subtracted the respective contribution of blank carbon from sample carbon. In detail, this means that, when ablating soil samples, we need to compare the resulting carbon signature with that of the reference peak from standard material that was homogeneous in carbon content. The subtraction then refines the resulting signals by a linearity correction, which involves using measured and true values for the CO2 reference gas.
A blank correction for isotope ratio measurement with small amounts of samples can be performed by regression or by subtraction (34,35) and calculated as described by Werner et al.: (36)
where A is the area of the m/z 44 peak.
The trapping time of 20 s needed for the complete transport of the sample gas suspension from a 3.8 mL cell to the first cryo-trap poses a constraint for sampling resolution; namely, the signal intensity from ablated carbon material had to be in excess of 0.3 Vs for it to be reproducible (Figure S-4b).
To calculate the ablated C amount, we used an acryl plate and measured the total ablated volume (Figure S-3a; C content 60%; density 1.19 g cm3; δ13CAcryl = −29.75 ± 0.06‰, relative to VPDB using EA-IRMS). We determined the ablated crater volume for different combinations of laser spot size and shot numbers (Figure S-3b; Table S1). The crater geometry and overall symmetry may influence the depth resolution and fractionation effects, which might not be strictly related only to the beam profile. The Nd:YAG laser was able to produce flat-bottom and straight-wall craters. (37,38) The crater geometry (Figure S-3b,c) maintained flat-bottom laser beam profiles during repeated ablations at a single spot, using focused laser light pulses with 10 and 40 μm operative diameters. Because of this crater assessment, we were able to calibrate the LA-IRMS signal to C amount and, thus, also determine sample size requirements for the reference measurements comparable to Moran et al. (25) The final limit of determination corresponded to a carbon amount of 0.6 ng for the 3.8 mL cell, which corresponded to a minimum of 20 μm ablated spot size (Figure 4a).

Figure 4

Figure 4. Detection limit of the LA-IRMS system given in C amount (a) for the cell with 3.8 mL active volume and (b) for the cell with 0.4 mL active volume (detected with an acryl plate with known ablated crater volume; see also Supporting Information).

High Resolution Image
Download MS PowerPoint Slide

Sensitivity Enhancement

In order to be able to detect carbon when using spots <20 μm in diameter, we built a second sample cell with reduced active volume (0.4 mL). We used it with decreased loading time for cryo-trapping in order to minimize blank signal accumulation in the cryo-traps (Figure 2). The isotopic signature of the blank was comparable to that of the 3.8 mL cell, but the contribution of the blank to the ablated signal was significantly smaller. The trapping time needed for the evacuation (transport efficiency) of the sample was best at 10 s (Figure S-5). A saturation of raw isotopic signal from the acryl plate was reached at a δ-value of −37.42 ± 0.37‰, irrespective of the loading time; this indicates that the blank contribution could then be neglected (Figure S-5a). The smaller cell finally yielded the same δ13C values as the larger cell after blank correction (Table 1; Table S-1). We conclude that operation with the small cell is feasible, which enables us to reduce the combination of spot size for laser ablation to 15 μm with 20 shots and to 10 μm with 40 shots. The limit of determination was calculated to be 0.3 ng C for the 0.4 mL cell, which corresponded to a minimum ablated spot size of 10 μm (Figure 5b).

Figure 5

Figure 5. Spatially resolved microanalysis of δ13C heterogeneity in a soil microaggregate structure from a cropped Luvisol field of 33% clay (53–250 μm aggregate fraction, 20 μm spot size, 40 shots per ablation). Raw δ13C values shown in red and blank corrected δ13C values, in black.

High Resolution Image
Download MS PowerPoint Slide
Table 1. Accuracy Tests of the LA-IRMS System with 3.8 and 0.4 mL Active Cell Volume
 laser ablation-IRMS 
 active volume 3.8 mLactive volume 0.4 mLEA-IRMS
sampleδ13C ± st.dev. (‰)offset (‰)nδ13C ± st.dev. (‰)offset (‰)nδ13C ± st.dev. (‰)n
acryl platea–29.68 ± 0.25–0.0739–29.77 ± 0.250.0222–29.75 ± 0.065
IAEA-CH-3–24.72 ± 0.780.00b30–24.80 ± 0.570.08b21–24.77 ± 0.065
Beech–27.05 ± 0.64–0.0427   –27.09 ± 0.025
a

Acryl plate sampling corresponded to 3.4 ng C in the 3.8 mL cell and 0.7 ng C in the 0.4 mL cell (see text for calculation).

b

IUPAC reference for δ13C value IAEA-CH-3 = −24.72 ± 0.04‰. (29)

Analyses of Environmental Samples

We first applied our methodology to soil microaggregates (sample set 1, long-term arable experiment station at Scheyern, Germany). We fixed the occluded microaggregate fraction in Araldite and detected spotwise the δ13C using the 3.8 mL cell (Figure 5). During the analyses of the embedded material, we randomly repeated the acryl plate standard measurement in order to have the reference measurements in the same sample run (Figure S-2c). The bulk soil and microaggregate fraction (53–250 μm) were characterized for their C isotope composition before using EA-IRMS and showed an average δ13C value of −25.10 ± 0.07‰ and −25.36 ± 0.42‰, respectively. However, the single isotopic signals in the ablated material showed a much larger variability, which reached a data spread >1‰ independent of ablation spot size (Table 2). In soil, such a shift in δ13C values corresponds to organic matter degradation along a depth interval of a few dm in native sites not experiencing a C3/C4 vegetation change, which may well comprise >1000 years of organic matter turnover and genesis. (39) Therefore, the accuracy of δ13C analyses for bulk soil or even a soil aggregate fraction in no way represents the true heterogeneity of processes involved in soil organic matter transformation and genesis. Instead, we have to conclude that there are hot spots of C accrual, even at microaggregate level, that originate from different isotope discrimination processes and, thus, probably from different organic molecules and, respectively, from different plant or microbial debris.
Table 2. δ13C in Spots Ablated with 20 and 30 μm Spot Size from Soil Microaggregatesa
fraction [μm]spot size [μm]LA-IRMS δ13C [‰]EA-IRMS δ13C ± s.d. [‰]
<2000  –25.10 ± 0.07
250–53 occluded20–25.28–25.36 ± 0.42
  –23.59 
  –26.83 
  –25.28 
  –24.23 
  –25.36 
  –25.21 
250–53 occluded30–27.36 
  –26.68 
  –23.90 
  –25.60 
  –24.98 
  –25.13 
a

Laser ablation revealed high spatial variability, which is not visible from standard EA-IRMS analysis. The δ13C was not influenced by spot size (3.8 mL cell active volume, mean isotope signal from 13 LA-IRMS measurements −25.34 ± 1.11‰ compared well to bulk sample EA-IRMS analysis).

Heterogeneous δ13C distribution not only is to be expected in soils but also has previously been found for tree rings (24) and may be expected as well for root exudation of C into soil as for nutrient uptake and related feeding of the microbial community. We detected the microscale shift in C isotope composition in a gradient ablated from the root to the root-to-soil contact zone (rhizosphere) and the soil matrix (Figures 6a,b and S-6). The root, which was from Miscanthus (sample set 2), clearly consisted of C4-photosynthesis derived C (with an average δ13C of −19‰, Figure 6a), while soil in about 300 μm distance did not yet show signs of C4-carbon input. However, signals had already mixed in less than a 300 μm distance, indicating that 25–50% of the C was gradually exchanged in this region. To our knowledge, this is the very first in situ detection of rhizosphere gradients using stable-isotope screening. Rhizosphere gradients evolve because of water and related nutrient uptake, which eventually cost carbon to feed the nutrient-mobilizing community and are frequently assumed to extend into a gradient of up to 1–4 mm. Figure 6a suggests that rhizosphere extension in terms of C exudation from roots to soil may even be limited to 100 μm, that is, very close to the rhizoplane. These findings shed new light on rhizosphere biochemistry, since getting hold of its extension has challenged research until now (e.g., ref (40)).

Figure 6

Figure 6. Spatial differences of isotopic signatures inside the root, rhizosphere area, and soil matrix from a Miscanthus root ablated with (a) constant spot size of 30 μm and 30 shot numbers and with (b) variable spot size of 15 μm and 40 shot numbers (white-colored signatures) and spot size of 10 μm and 80 shot numbers (black colored signatures), both performed on a 60 μm cross section; in-house reference acryl = −29.75 ± 0.04‰.

High Resolution Image
Download MS PowerPoint Slide
When using the same embedded material, but decreasing spot size to 10 μm, even a larger range of δ13C isotope values was found (Figure 6b). This range reached 13.76‰, which was slightly larger than the range detected with a spot size of 15 μm (Δδ13C = 13.25‰). While this may still be due to random hits of different hot spots in soil, none of the δ-values above −17‰ (Figure 6b) had been found using 30 μm-sized spots (Figure 6a). We attribute this to the improvement of our cell: only a spot size of 10 μm is able to discover the full range of isotope values in the environment (here, soils with C3/C4 vegetation change), while a spot size of 30 μm already includes the risk of averaging across a sampling area that is too large to detect realistic hot spots. As former attempts to track δ13C values in plant and soil had to rely on a spot size of at least 100–150 μm (e.g., ref (23)), we see our method developments as a clear step toward a now upcoming, in situ mapping of δ13C isotope values and discrimination processes in the environment.
In order to obtain an independent field replicate, we took another sample from 2 years of the C3/C4 vegetation change from the Terrestrial Observatory TERENO Selhausen, Germany. (3,32) Even though we only performed laser shots on sieved soil aggregates, we detected the full range of possible δ13C values, reflecting hotspots of both C3 and C4 plant origin (Figure 7). Again, this discovered range was almost as large as the difference between C3 and C4 plant species (Δδ13C = 12.44‰), even though the hot spots looked macroscopically similar. The results have two implications. From an analytical point of view, these data show that it is possible to resolve hot spots of C accrual with different 13C isotope discrimination in an environment even down to a spatial scale of 10 μm. From the environmental point of view, the data implies that it is possible to find microsites at which original C3 plant material had remained untouched in soil, while other places were comprised solely of the newly C4 carbon introduced; in other words, there are microsites with more or less 0–100% of C sequestration, separated by a distance of only a few micrometers.

Figure 7

Figure 7. Spatial differences of isotopic signatures ablated from 2 mm sieved soil with constant spot size of 10 μm and 60 shot numbers after 2 years of C3 to C4 vegetation change (Zea mais L., Selhausen; in-house reference acryl = −29.57 ± 0.32‰).

High Resolution Image
Download MS PowerPoint Slide

Conclusions and Implications

ARTICLE SECTIONS
Jump To
By adapting laser ablation isotope ratio monitoring to δ13C analysis in soil organic matter on the microscale, we found significant heterogeneity in soil microaggregates after C3/C4 vegetation change (>10‰), as well as in microaggregates that did not receive a vegetation change (3‰), and we were able to detect C4–C inputs from roots into soil. Hence, this technique allows us to spatially recognize hot spots of organic C turnover in soil, as well as of input dimensions of rhizodeposits and root exudates. The same will be possible in other environmental samples like sediments, geological and geoarcheological archives, or biological tissues. The achieved current spot size of 10 μm allows detection of natural δ13C abundance far below conventional IRMS routines, which is achieved here by minimizing the split of sample gas fluxes and by reducing active cell volume to 3.8 and 0.4 mL. Future challenges might be the automatization of the ablation procedure (communication between laser and IRMS equipment) and the extension to δ15N analysis, which requires a modified analytical setup for focusing on the N2 peak.

Supporting Information

ARTICLE SECTIONS
Jump To

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.analchem.9b00892.

  • One table and six figures showing the determination of carbon amount by measurements of crater depth on an acryl plate (Table S-1), configuration of the newly developed laser cells (Figure S-1), images of press-pellets from the ground and mixed standard substances (Figure S-2), images of spot depth and surface mapping of ablated spots (Figure S-3), deviation of the δ13C signal from referenced values due to the contribution of the blank signal (Figure S-4), adjustment of loading times in the cryo-trap (Figure S-5), and stable C isotope signatures of a Miscanthus rhizome and the surrounding soil (Figure S-6) (PDF)

Terms & Conditions

Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

Author Information

ARTICLE SECTIONS
Jump To
  • Corresponding Author
    • Andrei Rodionov - Institute of Crop Science and Resource Conservation (INRES), Soil Science and Soil Ecology, University of Bonn, Nussallee 13, Bonn 53115, Germany;  Present Address: A.R.: Soil Ecology, University of Bayreuth, Dr.-Hans-Frisch-Str. 1-3, 95448 Bayreuth, Germany;  Orcidhttp://orcid.org/0000-0001-5971-1948;  Email: [email protected]
  • Authors
    • Eva Lehndorff - Soil Ecology, University of Bayreuth, Dr.-Hans-Frisch-Str. 1-3, Bayreuth 95448, Germany
    • Ciprian C. Stremtan - Teledyne CETAC Technologies, 14306 Industrial Road, Omaha, Nebraska 68144, United States
    • Willi A. Brand - Max-Planck-Institute for Biogeochemistry, Beutenberg Campus, P.O. Box 100164, Jena 07701, Germany
    • Heinz-Peter Königshoven - Feinmechanische Werkstatt, Institute of Physical and Theoretical Chemistry, University of Bonn, Wegeler Str. 12, Bonn 53115, Germany
    • Wulf Amelung - Institute of Crop Science and Resource Conservation (INRES), Soil Science and Soil Ecology, University of Bonn, Nussallee 13, Bonn 53115, Germany
  • Notes
    The authors declare no competing financial interest.

Acknowledgments

ARTICLE SECTIONS
Jump To

We acknowledge the technician, Leona O’Connor, at Trinity College Dublin Center for Microscopy and Analysis, for performing the surface measurements. We also wish to thank members of the staff at Steinmann Institute, Nils Jung and Thomas Schulz at the University of Bonn, and Raphael Njul at the Bavarian Research Institute of Experimental Geochemistry and Geophysics (BGI), University of Bayreuth, for their support of the sample embedding and preparation. This work is associated with the MAD Soil project, which was funded by the DFG (Deutsche Forschungsgemeinschaft, Research Unit 2179). We very much acknowledge the help of two anonymous reviewers.

References

ARTICLE SECTIONS
Jump To

This article references 40 other publications.

  1. 1
    Köhler, P. Using the Suess effect on the stabile carbon isotope to distinguish the future from the past in radiocarbon. Environ. Res. Lett. 2016, 11, 124016,  DOI: 10.1088/1748-9326/11/12/124016
    Google Scholar
    There is no corresponding record for this reference.
  2. 2
    Beer, K. D.; Orellana, M. V.; Baliga, N. S. Modeling the evolution of C4 photosynthesis. Cell 2013, 153, 1427– 1429,  DOI: 10.1016/j.cell.2013.05.058
    Google Scholar
    2
    Modeling the evolution of C4 photosynthesis
    Beer, Karlyn D.; Orellana, Monica V.; Baliga, Nitin S.
    Cell (Cambridge, MA, United States) (2013), 153 (7), 1427-1429CODEN: CELLB5; ISSN:0092-8674. (Cell Press)
    FR OLa review. The prediction and verification of adaptive trajectories on macroevolutionary timescales have rarely been achieved for complex biol. systems. Employing a model linking biol. information at multiple scales, Heckmann et al. simulate likely sequences of evolutionary changes from C3 to C4 photosynthesis biochem.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtVWgt7rE&md5=81b2efe1c68a72c7fc39be37ead18569
  3. 3
    Kellogg, E. A. C4 photosynthesis. Curr. Biol. 2013, 23, R594– 9,  DOI: 10.1016/j.cub.2013.04.066
    Google Scholar
    3
    C4 photosynthesis
    Kellogg, Elizabeth A.
    Current Biology (2013), 23 (14), R594-R599CODEN: CUBLE2; ISSN:0960-9822. (Cell Press)
    A review. The no. of humans on earth is increasing, generating concerns about food security and spurring efforts throughout the world to increase the productivity of crops. If a way could be found to increase the yield of crops by, say, 20%, it would have immense impact on global food supplies. Fortunately, evolution has already crafted such a mechanism, known as C4 photosynthesis. The C4 pathway is in effect a turbocharger for the more conventional C3 pathway. Just as a turbocharger improves performance of an engine by forcing more air into the manifold, C4 improves photosynthetic performance by forcing CO2 into the std. C3 photosynthetic app. The added efficiency of this mechanism is obvious at a global level. Only about 3% of flowering plant species use the C4 pathway, but this relative handful of species account for 23% of the carbon fixed (primary productivity) in the world. The pathway occurs in several of the world's major crops, notably maize (corn) and sorghum, and in many of the species in use as biofuels, most importantly sugar cane; all of these are grasses in the family Poaceae. If a major C3 crop such as rice could be bred to use the C4 pathway, the economic impact would be immense.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtFCqtr7E&md5=8b4f50068ca8f7db76f0f597fc4c4ebc
  4. 4
    Moreno-Gutiérrez, C.; Dawson, T. E.; Nicolás, E.; Querejeta, J. I. Isotopes reveal contrasting water use strategies among coexisting plant species in a Mediterranean ecosystem. New Phytol. 2012, 196, 489– 496,  DOI: 10.1111/j.1469-8137.2012.04276.x
    Google Scholar
    4
    Isotopes reveal contrasting water use strategies among coexisting plant species in a Mediterranean ecosystem
    Moreno-Gutierrez, Cristina; Dawson, Todd E.; Nicolas, Emilio; Querejeta, Jose Ignacio
    New Phytologist (2012), 196 (2), 489-496CODEN: NEPHAV; ISSN:0028-646X. (Wiley-Blackwell)
    Summary : Variation in the stable carbon and oxygen isotope compn. (δ13C, Δ18O) of co-occurring plant species may reflect the functional diversity of water use strategies present in natural plant communities. We investigated the patterns of water use among 10 coexisting plant species representing diverse taxonomic groups and life forms in semiarid southeast Spain by measuring their leaf δ13C and Δ18O, the oxygen isotope ratio of stem water and leaf gas exchange rates. Across species, Δ18O was tightly neg. correlated with stomatal conductance (gs), whereas δ13C was pos. correlated with intrinsic water use efficiency (WUEi). Broad interspecific variation in Δ18O, δ13C and WUEi was largely detd. by differences in gs, as indicated by a strong pos. correlation between leaf δ13C and Δ18O across species. The 10 co-occurring species segregated along a continuous ecophysiol. gradient defined by their leaf δ13C and Δ18O, thus revealing a wide spectrum of stomatal regulation intensity and contrasting water use strategies ranging from profligate/opportunistic' (high gs, low WUEi) to conservative' (low gs, high WUEi). Coexisting species maintained their relative isotopic rankings in 2 yr with contrasting rainfall, suggesting the existence of species-specific isotopic niches' that reflect ecophysiol. niche segregation in dryland plant communities.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtlGjt77P&md5=a0241ffcb2f7936250cf6cf935d37c38
  5. 5
    Gebrekirstos, A.; van Noordwijk, M.; Neufeldt, H.; Mitlöhner, R. Relationships of stable carbon isotopes, plant water potential and growth: an approach to asses water use efficiency and growth strategies of dry land agroforestry species. Trees 2011, 25, 95– 102,  DOI: 10.1007/s00468-010-0467-0
    Google Scholar
    There is no corresponding record for this reference.
  6. 6
    Hartman, G.; Danin, A. Isotopic values of plants in relation to water availability in the Eastern Mediterranean region. Oecologia 2010, 162, 837– 852,  DOI: 10.1007/s00442-009-1514-7
    Google Scholar
    6
    Isotopic values of plants in relation to water availability in the Eastern Mediterranean region
    Hartman Gideon; Danin Avinoam
    Oecologia (2010), 162 (4), 837-52 ISSN:.
    Plant C and N isotope values often correlate with rainfall on global and regional scales. This study examines the relationship between plant isotopic values and rainfall in the Eastern Mediterranean region. The results indicate significant correlations between both C and N isotope values and rainfall in C(3) plant communities. This significant relationship is maintained when plant communities are divided by plant life forms. Furthermore, a seasonal increase in C isotope values is observed during the dry season while N isotope values remain stable across the wet and dry seasons. Finally, the isotopic pattern in plants originating from desert environments differs from those from Mediterranean environments because some desert plants obtain most of their water from secondary sources, namely water channeled by local topographic features rather than direct rainfall. From these results it can be concluded that water availability is the primary factor controlling C and N isotope variability in plant communities in the Eastern Mediterranean.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC3c7ovFyjug%253D%253D&md5=a6724a1e128bbb1f782cc1355a0708d2
  7. 7
    Hudson, A. M.; Quade, J.; Ali, G.; Boyle, D.; Bassett, S.; Huntington, K. W.; De los Santos, M. G.; Cohen, A. S.; Lin, K.; Wang, X. Stable C, O and clumped isotope systematics and 14C geochronology of carbonates from the Quaternary Chewaucan closed-basin lake system, Great Basin, USA: Implications for paleoenvironmental reconstructions using carbonates. Geochim. Cosmochim. Ac. 2017, 212, 274– 302,  DOI: 10.1016/j.gca.2017.06.024
    Google Scholar
    There is no corresponding record for this reference.
  8. 8
    Wilson, K. E.; Maslin, M. A.; Leng, M. J.; Kingston, J. D.; Deino, A. L.; Edgar, R. K.; Mackay, A. W. East African lake evidence for Pliocene millennial-scale climate variability. Geology 2014, 42, 955– 958,  DOI: 10.1130/G35915.1
    Google Scholar
    There is no corresponding record for this reference.
  9. 9
    Laskov, C.; Amelung, W.; Peiffer, S. Organic Matter Preservation in the Sediment of an Acidic Mining Lake. Environ. Sci. Technol. 2002, 36, 4218– 4223,  DOI: 10.1021/es010320y
    Google Scholar
    9
    Organic Matter Preservation in the Sediment of an Acidic Mining Lake
    Laskov, Christine; Amelung, Wulf; Peiffer, Stefan
    Environmental Science and Technology (2002), 36 (20), 4218-4223CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
    Sustainable management of acidic mining lakes requires knowledge of the origin and reactivity of its sedimentary org. matter. We identified different pools of org. matter (OM) in the Fe-rich sediment (up to 35%) of an acidic (pH 2.8) mining lake using δ13C-signals, C/N ratios, and the markers alkanes, lignin-derived phenols, and benzenepolycarboxylic acids (BPCAs). Addnl., a d. fractionation was applied to each sediment layer. Three fractions, aquatic (AOM), terrestrial (TOM), and lignite-derived (LOM) org. matter, were discriminated, of which AOM composes only a small fraction, with a min. at the sediment bottom. The terrestrial contribution to sedimentary OM is higher than that of AOM but still low throughout the sediment core, whereas lignite-derived OM constitutes the major carbon fraction, even in the upper sediment layers. The size of the carbon pools was quantified with a mass-balance approach, in which the BPCA content was utilized as an est. for the lignite fraction in combination with the δ13C-signals of the three C fractions. The largest amt. of OM was found in the heaviest (>2.4 g/cm3) of the three d. fractions of the two upper sediment layers, which implies strong interaction with iron hydroxides. Comparisons with carbon oxidn. rates revealed that besides the refractory origin of the OM, sorptive preservation by solid iron phases controls carbon reactivity in the sediment and, hence, the internal neutralization capacity of the lake system.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XmvFKrsrc%253D&md5=84c7c5e76a561d35d2f1f8f9f78027fa
  10. 10
    Derrien, D.; Amelung, W. Computing the mean residence time of soil carbon fractions using stable isotopes: impacts of the model framework. Europ. J. Soil Sci. 2011, 62, 237– 252,  DOI: 10.1111/j.1365-2389.2010.01333.x
    Google Scholar
    There is no corresponding record for this reference.
  11. 11
    Still, C. J.; Berry, J. A.; Collatz, G. J.; DeFries, R. S. Global distribution of C 3 and C 4 vegetation: Carbon cycle implications. Global Biogeochem. Cycles 2003, 17, 6-1– 6-14,  DOI: 10.1029/2001GB001807
    Google Scholar
    There is no corresponding record for this reference.
  12. 12
    Blagodatskaya, E.; Yuyukina, T.; Blagodatsky, S.; Kuzyakov, Y. Turnover of soil organic matter and of microbial biomass under C3–C4 vegetation change: Consideration of 13C fractionation and preferential substrate utilization. Soil Biol. Biochem. 2011, 43, 159– 166,  DOI: 10.1016/j.soilbio.2010.09.028
    Google Scholar
    12
    Turnover of soil organic matter and of microbial biomass under C3-C4 vegetation change: Consideration of 13C fractionation and preferential substrate utilization
    Blagodatskaya, E.; Yuyukina, T.; Blagodatsky, S.; Kuzyakov, Y.
    Soil Biology & Biochemistry (2011), 43 (1), 159-166CODEN: SBIOAH; ISSN:0038-0717. (Elsevier B.V.)
    Two processes contribute to changes of the δ13C signature in soil pools: 13C fractionation per se and preferential microbial utilization of various substrates with different δ13C signature. These two processes were disentangled by simultaneously tracking δ13C in three pools - soil org. matter (SOM), microbial biomass, dissolved org. carbon (DOC) - and in CO2 efflux during incubation of (1) soil after C3-C4 vegetation change, and (2) the ref. C3 soil. The study was done on the Ap horizon of a loamy Gleyic Cambisol developed under C3 vegetation. Miscanthus giganteus - a perennial C4 plant - was grown for 12 years, and the δ13C signature was used to distinguish between old' SOM (>12 years) and recent'Miscanthus-derived C (<12 years). The differences in δ13C signature of the three C pools and of CO2 in the ref. C3 soil were less than 1‰, and only δ13C of microbial biomass was significantly different compared to other pools. Nontheless, the neglecting of isotopic fractionation can cause up to 10% of errors in calcns. In contrast to the ref. soil, the δ13C of all pools in the soil after C3-C4 vegetation change was significantly different. Old C contributed only 20% to the microbial biomass but 60% to CO2. This indicates that most of the old C was decompd. by microorganisms catabolically, without being utilized for growth. Based on δ13C changes in DOC, CO2 and microbial biomass during 54 days of incubation in Miscanthus and ref. soils, we concluded that the main process contributing to changes of the δ13C signature in soil pools was preferential utilization of recent vs. old C (causing an up to 9.1‰ shift in δ13C values) and not 13C fractionation per se. Based on the δ13C changes in SOM, we showed that the estd. turnover time of old SOM increased by two years per yr in 9 years after the vegetation change. The relative increase in the turnover rate of recent microbial C was 3 times faster than that of old C indicating preferential utilization of available recent C vs. the old C. Combining long-term field observations with soil incubation reveals that the turnover time of C in microbial biomass was 200 times faster than in total SOM. Our study clearly showed that estg. the residence time of easily degradable microbial compds. and biomarkers should be done at time scales reflecting microbial turnover times (days) and not those of bulk SOM turnover (years and decades). This is necessary because the absence of C reutilization is a prerequisite for correct estn. of SOM turnover. We conclude that comparing the δ13C signature of linked pools helps calc. the relative turnover of old and recent pools.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsVGrs7zJ&md5=661f5b3001db53a25bc355f2611a7745
  13. 13
    Schemmel, F.; Mikes, T.; Rojay, B.; Mulch, A. The impact of topography on isotopes in precipitation across the Central Anatolian Plateau (Turkey). Am. J. Sci. 2013, 313, 61– 80,  DOI: 10.2475/02.2013.01
    Google Scholar
    13
    The impact of topography on isotopes in precipitation across the Central Anatolian Plateau (Turkey)
    Schemmel, Fabian; Mikes, Tamas; Rojay, Bora; Mulch, Andreas
    American Journal of Science (2013), 313 (2), 61-80CODEN: AJSCAP; ISSN:0002-9599. (Kline Geology Laboratory)
    Paleoelevation reconstructions of mountain belts and orogenic plateaus based on stable isotope climate and pptn. records benefit greatly from present-day calibrations that relate the fractionation of hydrogen (δD) and oxygen (δ18O) isotopes in pptn. to orog. rainfall. Here, we establish a first-order template of δD and δ18O of modern meteoric waters across the Central Anatolian Plateau (CAP) and its bordering Pontic and Taurus Mountains. We identify key regions in the plateau interior and along the plateau margins that have the potential to reliably record topog.-related paleotemperature and paleopptn. changes as recovered from stable isotope paleosol, fossil teeth or lipid proxy data. Based on δD and δ18O data of more than 480 surface water samples from small catchments and springs, we characterize moisture sources affecting the net isotopic budget of pptn. over the CAP and analyze how orog. rainout and plateau aridity shape modem patterns of δD and δ18O in pptn. The Taurus Mountains bordering the CAP to the south act as a major orog. barrier for transport of predominantly winter moisture and exhibit isotopic lapse rates of approx. -20‰/km for δD and -2.9‰/km for δ18O across an elevation range of nearly 3000 m. The Pontic Mountains at the northern margin of the CAP force perennial moisture to ascend and condensate revealing lapse rates of -19‰/km for δD and -2.6‰/km for δ18O. The difference in the predominant moisture source for the southern and northern margins of the CAP (North African vs. Atlantic air masses) is manifested in systematic north-south differences in near-sea level meteoric water compns. of Δ(δDN-S) ∼20 permil and Δ(δ18ON-S) ∼3 permil in a swath across the central part of the plateau. Stable isotope data from the semi-arid plateau interior with rainfall as low as 300 to 500 mm/yr and mean summer temps. attaining 23 °C, provide clear evidence for an evaporative regime that drastically affects surface water and runoff compns. and results in a local meteoric water line for the plateau interior that follows δD = 4.0 · δ18O - 29.3. Strongly evaporitic conditions contrast rainfall patterns along the plateau margins including their immediate leeward flanks where δD- and δ18O-elevation relationships are reliable predictors of modern topog.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXms1Ggtr8%253D&md5=be3863c72d7eebbc5b93015fc8b595e6
  14. 14
    Leier, A.; Quade, J.; DeCelles, P.; Kapp, P. Stable isotopic results from paleosol carbonate in South Asia: Paleoenvironmental reconstructions and selective alteration. Earth Planet. Sci. Lett. 2009, 279, 242– 254,  DOI: 10.1016/j.epsl.2008.12.044
    Google Scholar
    14
    Stable isotopic results from paleosol carbonate in South Asia: Paleoenvironmental reconstructions and selective alteration
    Leier, Andrew; Quade, Jay; DeCelles, P.; Kapp, P.
    Earth and Planetary Science Letters (2009), 279 (3-4), 242-254CODEN: EPSLA2; ISSN:0012-821X. (Elsevier B.V.)
    We measured δ18O and δ13C values of paleosol carbonate nodules from a variety of sedimentary units in southern Asia in order to reconstruct paleoenvironmental conditions and to evaluate for possible diagenetic alteration. Paleosol carbonate nodules were collected from Lower to Upper Cretaceous strata exposed in two locations in southern Tibet, and from Lower to Middle Miocene strata in northern India and Nepal. Addnl. samples were collected from stratigraphically adjacent marine carbonate units to test for possible resetting of stable isotope values. Based on the implausibly low δ18O values (∼ - 13‰) of most of the marine carbonate samples, we interpret the δ18O values of the assocd. paleosol carbonate nodules as being reset, and therefore unreliable for paleoenvironmental or paleoelevation reconstruction. Importantly, the δ18O values of both marine and nonmarine carbonate samples have been altered irresp. of texture, including micritic fabrics, suggesting textural criteria alone are insufficient to det. whether primary stable isotope values have been altered. In contrast, δ13C values of marine carbonate rocks fall within the expected primary isotopic range, and so by assocn. we interpret the δ13C values of paleosol carbonate from the same sections to have been unaffected by diagenesis. Using the δ13C values of paleosol carbonate nodules from Cretaceous strata in southern Tibet, atm. pCO2 is estd. to have been 1400-2000 ppmV between 130-120 Ma, and 2600-3200 ppmV between 100-90 Ma, consistent with previous ests. of pCO2 for these time periods. Paleosol carbonate nodules within early to middle Miocene strata in northern India and Nepal have av. δ13C values of -10.4‰, indicating virtually pure C3 vegetation and lower pCO2.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXisFaisr8%253D&md5=038157475bc9f6f843ed45f071819a8a
  15. 15
    Sikes, N. E.; Ashley, G. M. Stable isotopes of pedogenic carbonates as indicators of paleoecology in the Plio-Pleistocene (upper Bed I), western margin of the Olduvai Basin, Tanzania. J. Hum. Evol. 2007, 53, 574– 594,  DOI: 10.1016/j.jhevol.2006.12.008
    Google Scholar
    15
    Stable isotopes of pedogenic carbonates as indicators of paleoecology in the Plio-Pleistocene (upper Bed I), western margin of the Olduvai Basin, Tanzania
    Sikes Nancy E; Ashley Gail M
    Journal of human evolution (2007), 53 (5), 574-94 ISSN:0047-2484.
    Paleosol carbonates from trenches excavated as part of a landscape-scale project in Bed I of Olduvai Gorge, Tanzania, were analyzed for stable carbon and oxygen isotopic composition. The approximately 60,000-year interval ( approximately 1.845-1.785 Ma) above Tuff IB records evidence for lake and fluvial sequences, volcanic eruptions, eolian and pedogenic processes, and the development of a fluvial plain in the western margin of the basin. Significant temporal variation in the carbonate delta(18)O values records variation of local precipitation and supports the shifts in climatic conditions interpreted from the lithologic record. During this period, carbonate delta(13)C values varied between depositional facies indicating that the paleolandscape supported a local biomass of about 40-60% C(4) plants within a mosaic of grassy woodlands and wooded grasslands. The lithologic and stable isotope record in this small lake basin indicates the area was much wetter, with more woody C(3) plants, during this interval than is the semi-arid area today. The record also reflects the variation in climatic conditions (wet/dry) documented by other global climate proxies for this time.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD1czjs1aisg%253D%253D&md5=cfe518ba380657bd3e903329297b8894
  16. 16
    Sankaran, M.; Hanan, N. P.; Scholes, R. J.; Ratnam, J.; Augustine, D. J.; Cade, B. S.; Gignoux, J.; Higgins, S. I.; Le Roux, X.; Ludwig, F.; Ardo, J.; Banyikwa, F.; Bronn, A.; Bucini, G.; Caylor, K. K.; Coughenour, M. B.; Diouf, A.; Ekaya, W.; Feral, C. J.; February, E. C.; Frost, P. G. H.; Hiernaux, P.; Hrabar, H.; Metzger, K. L.; Prins, H. H. T.; Ringrose, S.; Sea, W.; Tews, J.; Worden, J.; Zambatis, N. Determinants of woody cover in African savannas. Nature 2005, 438, 846– 849,  DOI: 10.1038/nature04070
    Google Scholar
    16
    Determinants of woody cover in African savannas
    Sankaran, Mahesh; Hanan, Niall P.; Scholes, Robert J.; Ratnam, Jayashree; Augustine, David J.; Cade, Brian S.; Gignoux, Jacques; Higgins, Steven I.; Le Roux, Xavier; Ludwig, Fulco; Ardo, Jonas; Banyikwa, Feetham; Bronn, Andries; Bucini, Gabriela; Caylor, Kelly K.; Coughenour, Michael B.; Diouf, Alioune; Ekaya, Wellington; Feral, Christie J.; February, Edmund C.; Frost, Peter G. H.; Hiernaux, Pierre; Hrabar, Halszka; Metzger, Kristine L.; Prins, Herbert H. T.; Ringrose, Susan; Sea, William; Tews, Joerg; Worden, Jeff; Zambatis, Nick
    Nature (London, United Kingdom) (2005), 438 (7069), 846-849CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)
    Savannas are globally important ecosystems of great significance to human economies. In these biomes, which are characterized by the co-dominance of trees and grasses, woody cover is a chief determinant of ecosystem properties. The availability of resources (water, nutrients) and disturbance regimes (fire, herbivory) are thought to be important in regulating woody cover, but perceptions differ on which of these are the primary drivers of savanna structure. Here we show, using data from 854 sites across Africa, that max. woody cover in savannas receiving a mean annual pptn. (MAP) of less than ∼650 mm is constrained by, and increases linearly with, MAP. These arid and semi-arid savannas may be considered 'stable' systems in which water constrains woody cover and permits grasses to coexist, while fire, herbivory and soil properties interact to reduce woody cover below the MAP-controlled upper bound. Above a MAP of ∼650 mm, savannas are 'unstable' systems in which MAP is sufficient for woody canopy closure, and disturbances (fire, herbivory) are required for the coexistence of trees and grass. These results provide insights into the nature of African savannas and suggest that future changes in pptn. may considerably affect their distribution and dynamics.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1ynsrrP&md5=9d8498bc8f611c5b9f0922e214978f74
  17. 17
    van Malderen, S. J. M.; Laforce, B.; van Acker, T.; Vincze, L.; Vanhaecke, F. Imaging the 3D trace metal and metalloid distribution in mature wheat and rye grains via laser ablation-ICP-mass spectrometry and micro-X-ray fluorescence spectrometry. J. Anal. At. Spectrom. 2017, 32, 289– 298,  DOI: 10.1039/C6JA00357E
    Google Scholar
    17
    Imaging the 3D trace metal and metalloid distribution in mature wheat and rye grains via laser ablation-ICP-mass spectrometry and micro-X-ray fluorescence spectrometry
    Van Malderen, Stijn J. M.; Laforce, Brecht; Van Acker, Thibaut; Vincze, Laszlo; Vanhaecke, Frank
    Journal of Analytical Atomic Spectrometry (2017), 32 (2), 289-298CODEN: JASPE2; ISSN:0267-9477. (Royal Society of Chemistry)
    Toxic trace metals and metalloids in human nutrient sources pose a severe health risk, and the processes governing metal accumulation should hence be well understood. In this work, the spatial distribution of toxic trace metals/metalloids and micronutrients (Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb) in mature wheat (Triticum aestivum L.) and rye (Secale cereale L.) grains at typical exposure levels was visualized and quantified via laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) by serial sectioning. The bulk concns. of these elements were also detd. by pneumatic nebulisation-ICP-MS. Furthermore, longitudinal sections were scanned using μ-X-ray fluorescence spectrometry to confirm the major element distribution. Serial sectioning in this study was realized via a polishing strategy. Although the methodol. is time-consuming and laborious, it enables to access 3D information for samples which cannot be sectioned using a microtome on a depth scale that would otherwise be inaccessible by a laser probe. In the elemental images, strong local enrichment patterns for Mn and Zn are apparent in the aleurone layer/seed coat, vascular tissue of the crease, and embryonic tissue, whereas Cr, As, Cd and Pb have been mainly accumulated in the grain endosperm as a result of different transport and storage dynamics.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvF2gurnO&md5=5c71ba8d42e15ae6d83a01f96b6723ce
  18. 18
    van Malderen, S. J. M.; Vergucht, E.; De Rijcke, M.; Janssen, C.; Vincze, L.; Vanhaecke, F. Quantitative Determination and Subcellular Imaging of Cu in Single Cells via Laser Ablation-ICP-Mass Spectrometry Using High-Density Microarray Gelatin Standards. Anal. Chem. 2016, 88, 5783– 5789,  DOI: 10.1021/acs.analchem.6b00334
    Google Scholar
    18
    Quantitative Determination and Subcellular Imaging of Cu in Single Cells via Laser Ablation-ICP-Mass Spectrometry Using High-Density Microarray Gelatin Standards
    Van Malderen, Stijn J. M.; Vergucht, Eva; De Rijcke, Maarten; Janssen, Colin; Vincze, Laszlo; Vanhaecke, Frank
    Analytical Chemistry (Washington, DC, United States) (2016), 88 (11), 5783-5789CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
    This manuscript describes the development and characterization of a high-d. microarray calibration std., manufd. inhouse and designed to overcome the limitations in precision, accuracy, and throughput of current calibration approaches for the quantification of elemental concns. on the cellular level using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS). As a case study, the accumulation of Cu in the model organism Scrippsiella trochoidea resulting from transition metal exposure (ranging from 0.5 to 100 μg/L) was evaluated. After the Cu exposure, cells of this photosynthetic dinoflagellate were treated with a crit. point drying protocol, transferred to a carbon stub, and sputter-coated with a Au layer for SEM (SEM) anal. In subsequent LA-ICPMS anal., approx. 100 cells of each population were individually ablated. This approach permitted the evaluation of the mean concn. of Cu in the cell population across different exposure levels and also allowed the examn. of the cellular distribution of Cu within the populations. In a cross-validation exercise, subcellular LA-ICPMS imaging was demonstrated to corroborate synchrotron radiation confocal X-ray fluorescence (SR-XRF) microimaging of single cells investigated under in vivo conditions.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xnt12rsrY%253D&md5=4e6b5d9cf4155b2114dad93e6ed3ed5d
  19. 19
    Wu, B.; Becker, J. S. Imaging of elements and molecules in biological tissues and cells in the low-micrometer and nanometer range. Int. J. Mass Spectrom. 2011, 307, 112– 122,  DOI: 10.1016/j.ijms.2011.01.019
    Google Scholar
    19
    Imaging of elements and molecules in biological tissues and cells in the low-micrometer and nanometer range
    Wu, Bei; Becker, J. Sabine
    International Journal of Mass Spectrometry (2011), 307 (1-3), 112-122CODEN: IMSPF8; ISSN:1387-3806. (Elsevier B.V.)
    A review. Investigation of small areas of biol. tissues or single cells is of particular interest in the life sciences. Chem. imaging in such samples is able to provide the spatial distribution as well as concns. of elements and mols. present in the sample. At present, the anal. techniques supporting chem. imaging are under intensive development with respect to higher spatial resoln. and higher sensitivity and accuracy. In this review, we will focus on the state of the art of advanced mass spectrometric techniques such as secondary ionization mass spectrometry (SIMS), imaging matrix-assisted laser desorption/ionization mass spectrometry (imaging MALDI-MS), nano-scale laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) vs. non-mass spectrometric techniques, for instance, synchrotron-based X-ray fluorescence and scanning near-field optical microscopy (SNOM) assist Raman spectroscopy, with lateral resoln. down to low-micrometer and nanometer scales. The outstanding features and drawbacks of each technique are also discussed regarding their application on the study of biol. samples. The promising future of imaging mass spectrometric techniques, esp. nano-scale LA-ICP-MS, for application in biochem. studies with high spatial resoln. down to the nanometer range is also discussed.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXht1WktLrE&md5=4eaf89abc0fe321da3fd938ced7705d3
  20. 20
    Limbeck, A.; Galler, P.; Bonta, M.; Bauer, G.; Nischkauer, W.; Vanhaecke, F. Recent advances in quantitative LA-ICP-MS analysis: challenges and solutions in the life sciences and environmental chemistry. Anal. Bioanal. Chem. 2015, 407, 6593– 6617,  DOI: 10.1007/s00216-015-8858-0
    Google Scholar
    20
    Recent advances in quantitative LA-ICP-MS analysis: challenges and solutions in the life sciences and environmental chemistry
    Limbeck, Andreas; Galler, Patrick; Bonta, Maximilian; Bauer, Gerald; Nischkauer, Winfried; Vanhaecke, Frank
    Analytical and Bioanalytical Chemistry (2015), 407 (22), 6593-6617CODEN: ABCNBP; ISSN:1618-2642. (Springer)
    A review. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is a widely accepted method for direct sampling of solid materials for trace elemental anal. The no. of reported applications is high and the application range is broad; besides geochem., LA-ICP-MS is mostly used in environmental chem. and the life sciences. This review focuses on the application of LA-ICP-MS for quantification of trace elements in environmental, biol., and medical samples. The fundamental problems of LA-ICP-MS, such as sample-dependent ablation behavior and elemental fractionation, can be even more pronounced in environmental and life science applications as a result of the large variety of sample types and conditions. Besides variations in compn., the range of available sample states is highly diverse, including powders (e.g., soil samples, fly ash), hard tissues (e.g., bones, teeth), soft tissues (e.g., plants, tissue thin-cuts), or liq. samples (e.g., whole blood). Within this article, quantification approaches that have been proposed in the past are critically discussed and compared regarding the results obtained in the applications described. Although a large variety of sample types is discussed within this article, the quantification approaches used are similar for many anal. questions and have only been adapted to the specific questions. Nevertheless, none of them proved to be a universally applicable method.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFOisr%252FI&md5=fbc1838ed42ad908fae0b174797a477b
  21. 21
    Scarciglia, F.; Barca, D.; De Rosa, R.; Pulice, I. Application of laser ablation ICP-MS and traditional micromorphological techniques to the study of an Alfisol (Sardinia, Italy) in thin sections: Insights into trace element distribution. Geoderma 2009, 152, 113– 126,  DOI: 10.1016/j.geoderma.2009.05.021
    Google Scholar
    21
    Application of laser ablation ICP-MS and traditional micromorphological techniques to the study of an Alfisol (Sardinia, Italy) in thin sections: Insights into trace element distribution
    Scarciglia, Fabio; Barca, Donatella; De Rosa, Rosanna; Pulice, Iolanda
    Geoderma (2009), 152 (1-2), 113-126CODEN: GEDMAB; ISSN:0016-7061. (Elsevier B.V.)
    An innovative methodol. approach is proposed in this study, based on the chem. anal. of different portions of soil horizons (illuvial pedofeatures, pedogenic matrix and skeletal parent rock fragments) by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), assocd. with traditional micromorphol. (optical and SEM) techniques. Validation of the LA-ICP-MS technique provides in situ accurate and reproducible (RSD 13-18%) anal. of low concn. trace elements and rare earth elements (REE) in soil samples (0.001-0.1 ppm). Analyses were carried out on thin sections prepd. from undisturbed soil samples, collected from three different Bt (argillic, i.e. clay-illuviated) horizons in an Alfisol from the Muravera area (southeastern Sardinia, Italy). The main aims were (i) to develop and test the reliability of a LA-ICP-MS anal. method on soil thin sections and (ii) to explore the idea that concns. of trace and rare earth elements in the different portions of a soil profile can be used to investigate their distribution, as a response to pedogenetic processes. The three horizons show similar features, particularly in terms of element concns. and patterns. By comparing the concn. of REE and other trace elements in the clay coatings, the soil matrix and the skeletal rock fragments in the same horizon, a general enrichment trend is obsd. from the parent rock to the pedogenic matrix up to the illuvial pedofeatures, suggesting a prominent role of pedogenetic processes in element fractionation and distribution during weathering. In particular, the highest concn. of trace elements (and specifically REE) in clay coatings, which represent the most mobile solid phase in the soil profile, indicates that the former can be used as a reliable indicator of soil weathering if a preliminary assessment of the presence of clay coatings is achieved. In addn., the discontinuous trend of some trace elements among soil features of different horizons is consistent with field evidence of slope dynamics, marked by an erosive and depositional discontinuity along the soil profile.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXptFGnt7s%253D&md5=31a3c8c902bb4456f46ae618425bbd17
  22. 22
    Spötl, C.; Mattey, D. Stable isotope microsampling of speleothems for palaeoenvironmental studies: A comparison of microdrill, micromill and laser ablation techniques. Chem. Geol. 2006, 235, 48– 58,  DOI: 10.1016/j.chemgeo.2006.06.003
    Google Scholar
    There is no corresponding record for this reference.
  23. 23
    Bruneau, P. M. C.; Ostle, N.; Davidson, D. A.; Grieve, I. C.; Fallick, A. E. Determination of rhizosphere 13C pulse signals in soil thin sections by laser ablation isotope ratio mass spectrometry. Rapid Commun. Mass Spectrom. 2002, 16, 2190– 2194,  DOI: 10.1002/rcm.740
    Google Scholar
    23
    Determination of rhizosphere 13C pulse signals in soil thin sections by laser ablation isotope ratio mass spectrometry
    Bruneau, Patricia M. C.; Ostle, Nick; Davidson, Donald A.; Grieve, Ian C.; Fallick, Anthony E.
    Rapid Communications in Mass Spectrometry (2002), 16 (23), 2190-2194CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)
    In grassland ecosystems, soil animals act as key soil engineers and architects. The diversity of soil animals is also a regulator of ecosystem carbon flow. However, our understanding of the link between soil animals, carbon fluxes and soil phys. organization remains poor. An integrated approach based on soil micromorphol. and laser ablation stable isotope ratio mass spectrometry (LA-IRMS) was developed to provide spatially distributed data of pulse-derived 13C trace from roots in the soil environment. This paper describes the development and testing of a LA-IRMS 13C/12C anal. method on soil thin sections as a means to det. the fate of root carbon derived from photosynthesis into soil. Results from this work demonstrated (1) that microscale δ13C (‰) anal. could be made on targeted features located within a soil thin section and (2) that LA-IRMS δ13C (‰) measurements made on samples obtained from 13CO2 pulse labeled plant-soil blocks confirmed the presence of recent photosynthates in the rhizosphere (1 and 4 wk post-pulse).
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XptlGrsr0%253D&md5=79393089eb989c96be41549b4f82853b
  24. 24
    Schulze, B.; Wirth, C.; Linke, P.; Brand, W. A.; Kuhlmann, I.; Horna, V.; Schulze, E.-D. Laser ablation-combustion-GC-IRMS--a new method for online analysis of intra-annual variation of delta13C in tree rings. Tree Physiol. 2004, 24, 1193– 1201,  DOI: 10.1093/treephys/24.11.1193
    Google Scholar
    24
    Laser ablation-combustion-GC-IRMS - a new method for online analysis of intra-annual variation of δ13C in tree rings
    Schulze, Birgit; Wirth, Christian; Linke, Petra; Brand, Willi A.; Kuhlmann, Iris; Horna, Viviana; Schulze, Ernst-Detlef
    Tree Physiology (Victoria, BC, Canada) (2004), 24 (11), 1193-1201CODEN: TRPHEM; ISSN:0829-318X. (Heron Publishing)
    The authors present a new, rapid method for high-resoln. online detn. of δ13C in tree rings, combining laser ablation (LA), combustion (C), gas chromatog. (GC) and isotope ratio mass spectrometry (IRMS) (LA-C-GC-IRMS). Sample material was extd. every 6 min with a UV laser from a tree core, leaving 40-μm-wide holes. Ablated wood dust was combusted to CO2 at 700 °C, sepd. from other gases on a GC column and injected into an isotope ratio mass spectrometer after removal of water vapor. The measurements were calibrated against an internal and an external std. The tree core remained intact and could be used for subsequent dendrochronol. and dendrochem. analyses. Cores from two Scots pine trees (Pinus sylvestris spp. sibirica Lebed.) from central Siberia were sampled. Inter- and intra-annual patterns of δ13C in whole-wood and lignin-extd. cores were indistinguishable apart from a const. offset, suggesting that lignin extn. is unnecessary for this method. Comparison with the conventional method (microtome slicing, elemental anal. and IRMS) indicated high accuracy of the LA-C-GC-IRMS measurements. Patterns of δ13C along three parallel ablation lines on the same core showed high congruence. A conservative est. of the precision was ±0.24‰. Isotopic patterns of the two Scots pine trees were broadly similar, indicating a signal related to the forest stand's climate history. The max. variation in δ13C over 22 years was about 5‰, ranging from -27 to -22.3‰. The most obvious pattern was a sharp decline in δ13C during latewood formation and a rapid increase with spring early growth. The authors conclude that the LA-C-GC-IRMS method will be useful in elucidating short-term climate effects on the δ13C signal in tree rings.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtFahtLnE&md5=37346623dc69e3be14af9acc75cf25e6
  25. 25
    Moran, J. J.; Newburn, M. K.; Alexander, M. L.; Sams, R. L.; Kelly, J. F.; Kreuzer, H. W. Laser ablation isotope ratio mass spectrometry for enhanced sensitivity and spatial resolution in stable isotope analysis. Rapid Commun. Mass Spectrom. 2011, 25, 1282– 1290,  DOI: 10.1002/rcm.4985
    Google Scholar
    25
    Laser ablation isotope ratio mass spectrometry for enhanced sensitivity and spatial resolution in stable isotope analysis
    Moran, James J.; Newburn, Matt K.; Alexander, M. Lizabeth; Sams, Robert L.; Kelly, James F.; Kreuzer, Helen W.
    Rapid Communications in Mass Spectrometry (2011), 25 (9), 1282-1290CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)
    Stable isotope anal. permits the tracking of phys., chem., and biol. reactions and source materials at a wide variety of spatial scales. We present a laser ablation isotope ratio mass spectrometry (LA-IRMS) method that enables δ13C measurement of solid samples at 50 μm spatial resoln. The method does not require sample pre-treatment to phys. sep. spatial zones. We use laser ablation of solid samples followed by quant. combustion of the ablated particulates to convert sample carbon into CO2. Cryofocusing of the resulting CO2 coupled with modulation in the carrier flow rate permits coherent peak introduction into an isotope ratio mass spectrometer, with only 65 ng carbon required per measurement. We conclusively demonstrate that the measured CO2 is produced by combustion of laser-ablated aerosols from the sample surface. We measured δ13C for a series of solid compds. using laser ablation and traditional solid sample anal. techniques. Both techniques produced consistent isotopic results but the laser ablation method required over two orders of magnitude less sample. We demonstrated that LA-IRMS sensitivity coupled with its 50 μm spatial resoln. could be used to measure δ13C values along a length of hair, making multiple sample measurements over distances corresponding to a single day's growth. This method will be highly valuable in cases where the δ13C anal. of small samples over prescribed spatial distances is required. Suitable applications include forensic anal. of hair samples, investigations of tightly woven microbial systems, and cases of surface anal. where there is a sharp delineation between different components of a sample. Copyright © 2011 John Wiley & Sons, Ltd.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXks1ajtrc%253D&md5=a4c0a811e92dcf855770cc72a393ca4d
  26. 26
    van Roij, L.; Sluijs, A.; Laks, J. J.; Reichart, G.-J. Stable carbon isotope analyses of nanogram quantities of particulate organic carbon (pollen) with laser ablation nano combustion gas chromatography/isotope ratio mass spectrometry. Rapid Commun. Mass Spectrom. 2017, 31, 47– 58,  DOI: 10.1002/rcm.7769
    Google Scholar
    26
    Stable carbon isotope analyses of nanogram quantities of particulate organic carbon (pollen) with laser ablation nano combustion gas chromatography/isotope ratio mass spectrometry
    van Roij, Linda; Sluijs, Appy; Laks, Jelmer J.; Reichart, Gert-Jan
    Rapid Communications in Mass Spectrometry (2017), 31 (1), 47-58CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)
    Analyses of stable carbon isotope ratios (δ13C values) of org. and inorg. matter remains have been instrumental for much of the understanding of present and past environmental and biol. processes. Until recently, the anal. window of such analyses has been limited to samples contg. at least several μg of carbon. Here the authors present a setup combining laser ablation, nano combustion gas chromatog. and isotope ratio mass spectrometry (LA/nC/GC/IRMS). A deep UV (193 nm) laser was used for optimal fragmentation of org. matter with min. fractionation effects and an exceptionally small ablation chamber and combustion oven were used to reduce the min. sample mass requirement compared with previous studies. Analyses of the international IAEA CH-7 polyethylene std. show optimal accuracy and precision better than 0.5‰, when measuring at least 42 ng C. Application to untreated modern Eucalyptus globulus (C3 plant) and Zea mays (C4 plant) pollen grains shows an ∼16‰ offset between these species. Within each single Z. mays pollen grain, replicate analyses show almost identical δ13C values. Thus, isotopic offsets between individual pollen grains exceed anal. uncertainties, therefore probably reflecting interspecimen variability of ∼0.5-0.9‰. These promising results set the stage for studying both δ13C values and natural carbon isotopic variability between single specimens of a single population of all kinds of org. particles yielding tens of nanograms of carbon.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitVGqtrnP&md5=d9b99042b556ba2fe81a8b08be63f178
  27. 27
    Brand, W. A. PreCon: A Fully Automated Interface for the Pre-Gc Concentration of Trace Gases on Air for Isotopic Analysis. Isot. Environ. Health Stud. 1995, 31, 277– 284,  DOI: 10.1080/10256019508036271
    Google Scholar
    27
    PreCon. A fully automated interface for the pre-GC concentration of trace gases in air for isotopic analysis
    Brand, W. A.
    Isotopes in Environmental and Health Studies (1995), 31 (3-4), 277-84CODEN: IEHSF8 ISSN:. (Gordon & Breach)
    For the high precision isotope anal. of atm. trace gases a computer controlled concn. interface was developed. From small air samples it collects either N2O or CO2 derived from CH4 (at concn. of 0.3 and 1.7 ppm for N2O and CH4, resp.) into a small diam. cold trap (-196°) and interfaces via GC and open split to an isotope ratio mass spectrometer (Finnigan MAT 252) for online isotope evaluation. External preproducibilities for repeated measurements of 100 mL air samples from the same source of <0.2‰ (δ-notation) were achieved for 13C/12C from CH4 and for 15N/14N and 18O/16O from N2O. The precision is adequate to monitor the isotope changes in these gases during a day's course.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XntVegsA%253D%253D&md5=1149bb8292fda8436ffe9cc30eae5748
  28. 28
    Günther, D.; Hattendorf, B. Solid sample analysis using laser ablation inductively coupled plasma mass spectrometry. TrAC, Trends Anal. Chem. 2005, 24, 255– 265,  DOI: 10.1016/j.trac.2004.11.017
    Google Scholar
    28
    Solid sample analysis using laser ablation inductively coupled plasma mass spectrometry
    Guenther, Detlef; Hattendorf, Bodo
    TrAC, Trends in Analytical Chemistry (2005), 24 (3), 255-265CODEN: TTAEDJ; ISSN:0165-9936. (Elsevier B.V.)
    A review. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a highly accepted, widely used method for the detn. of major, minor and trace elements in solids, as well as isotope-ratio measurements. However, it suffers from nonstoichiometric effects occurring during sampling, aerosol transport, vaporization, atomization and ionization within the ICP, described as elemental fractionation. This matrix-dependent phenomenon was the limitation for quant. anal. without matrix-matched calibration stds. Significant insights into the processes responsible for elemental fractionation were obtained and, with improved understanding of LA-ICP-MS, a variety of strategies for more precise, more accurate quant. analyses were developed. This review aims to summarize recent developments in LA-ICP-MS based on the fundamental understanding of the LA process and particle formation but also includes the importance of the ICP and its operating conditions. Figures of merit and new trends in quantification to demonstrate the capabilities of this direct solid-sampling technique are discussed. The authors present a few selected applications to underline why LA is a fast-expanding anal. technique.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhs12kurc%253D&md5=ed53beb61eb6a5f6c14b5115dbb8cc92
  29. 29
    Brand, W. A.; Coplen, T. B.; Vogl, J.; Rosner, M.; Prohaska, T. Assessment of international reference materials for isotope-ratio analysis (IUPAC Technical Report). Pure Appl. Chem. 2014, 86, 425– 467,  DOI: 10.1515/pac-2013-1023
    Google Scholar
    29
    Assessment of international reference materials for isotope-ratio analysis (IUPAC Technical Report)
    Brand, Willi A.; Coplen, Tyler B.; Vogl, Jochen; Rosner, Martin; Prohaska, Thomas
    Pure and Applied Chemistry (2014), 86 (3), 425-467CODEN: PACHAS; ISSN:0033-4545. (Walter de Gruyter, Inc.)
    A review. Since the early 1950s, the no. of international measurement stds. for anchoring stable isotope delta scales has mushroomed from 3 to more than 30, expanding to more than 25 chem. elements. With the development of new instrumentation, along with new and improved measurement procedures for studying naturally occurring isotopic abundance variations in natural and tech. samples, the no. of internationally distributed, secondary isotopic ref. materials with a specified delta value has blossomed in the last six decades to more than 150 materials. More than half of these isotopic ref. materials were produced for isotope-delta measurements of seven elements: H, Li, B, C, N, O, and S. The no. of isotopic ref. materials for other, heavier elements has grown considerably over the last decade. Nevertheless, even primary international measurement stds. for isotope-delta measurements are still needed for some elements, including Mg, Fe, Te, Sb, Mo, and Ge. It is recommended that authors publish the delta values of internationally distributed, secondary isotopic ref. materials that were used for anchoring their measurement results to the resp. primary stable isotope scale.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXmslGlt7k%253D&md5=68bb686894fe9734166102f2e62e6a81
  30. 30
    Krause, L.; Rodionov, A.; Schweizer, S. A.; Siebers, N.; Lehndorff, E.; Klumpp, E.; Amelung, W. Microaggregate stability and storage of organic carbon is affected by clay content in arable Luvisols. Soil Tillage Res. 2018, 182, 123– 129,  DOI: 10.1016/j.still.2018.05.003
    Google Scholar
    There is no corresponding record for this reference.
  31. 31
    Glisczynski, F. v.; Pude, R.; Amelung, W.; Sandhage-Hofmann, A. Biochar-compost substrates in short-rotation coppice: Effects on soil and trees in a three-year field experiment. J. Plant Nutr. Soil Sci. 2016, 179, 574– 583,  DOI: 10.1002/jpln.201500545
    Google Scholar
    There is no corresponding record for this reference.
  32. 32
    Schiedung, H.; Tilly, N.; Hütt, C.; Welp, G.; Brüggemann, N.; Amelung, W. Spatial controls of topsoil and subsoil organic carbon turnover under C3–C4 vegetation change. Geoderma 2017, 303, 44– 51,  DOI: 10.1016/j.geoderma.2017.05.006
    Google Scholar
    32
    Spatial controls of topsoil and subsoil organic carbon turnover under C3-C4 vegetation change
    Schiedung, H.; Tilly, N.; Huett, C.; Welp, G.; Brueggemann, N.; Amelung, W.
    Geoderma (2017), 303 (), 44-51CODEN: GEDMAB; ISSN:0016-7061. (Elsevier B.V.)
    Soil org. carbon (SOC) is often heterogeneously distributed in arable fields and so is probably its turnover. We hypothesized that the spatial patterns of SOC turnover are controlled by basic soil properties like soil texture and the amt. of rock fragments. To test this hypothesis, we cultivated maize as a C4 plant on a heterogeneous arable field (155 × 60 m) that had formerly been solely cultivated with C3 crops, and monitored the incorporation of isotopically heavier maize-derived C into SOC by stable 13C isotope analyses. To obtain a homogeneous input of C4 biomass into the C3 soil across the field, we chopped the aboveground maize biomass after harvest in autumn and re-spread it uniformly over the field. Subsequently, the soil was grubbed and then ploughed in the next spring. In addn., we assessed the spatial patterns of SOC stocks, amt. of rock fragments and texture, as well as potential soil org. matter (SOM) degradability by ex-situ soil respiration measurements. Heterogeneity of maize growth was monitored as a covariate using laser scanning and satellite images. After two years, maize C had substituted 7.4 ± 3.2% of SOC in the topsoil (0-30 cm) and 2.9 ± 1.7% of SOC in the subsoil (30-50 cm). Assuming that monoexponential decay mainly drove this SOC substitution, this resulted in mean residence times (MRT) of SOC in the range of 30 ± 12 years for the topsoil and of 87 ± 45 years for the subsoil, resp. Variation in topsoil MRT was related to potential CO2 release during soil incubation (R2 = 0.51), but not to basic soil properties. In the subsoil, in contrast, the variation of maize C incorporation into the SOC pool was controlled by variations in maize yield (R2 = 0.44), which also exhibited a pronounced spatial variability (0.84 to 1.94 kg dry biomass m-2), and which was neg. correlated with the amt. of rock fragments (R2 = 0.48, p < 0.001). We assume that heterogeneous input of belowground root biomass blurs the causal interactions between the spatial heterogeneity of soil properties and the related patterns of SOC turnover, and conclude that spatial patterns of SOC turnover are not easily predictable by std. soil analyses.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXotlSqu7c%253D&md5=68a8d5072604888a3ac9d0a2193f1222
  33. 33
    Jeong, S. H.; Borisov, O. V.; Yoo, J. H.; Mao, X. L.; Russo, R. E. Effects of Particle Size Distribution on Inductively Coupled Plasma Mass Spectrometry Signal Intensity during Laser Ablation of Glass Samples. Anal. Chem. 1999, 71, 5123– 5130,  DOI: 10.1021/ac990455a
    Google Scholar
    33
    Effects of Particle Size Distribution on Inductively Coupled Plasma Mass Spectrometry Signal Intensity during Laser Ablation of Glass Samples
    Jeong, S. H.; Borisov, O. V.; Yoo, J. H.; Mao, X. L.; Russo, R. E.
    Analytical Chemistry (1999), 71 (22), 5123-5130CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
    The relation between laser-generated particles and ICPMS signal intensity was studied using single-pulse laser ablation sampling of solids. The particle size distribution of glass samples was measured using an optical particle counter for different laser ablation conditions. Ablation of a new surface produced fewer particles and lower ICPMS signal intensity than a preablated surface. Laser power d. of 0.4-0.5 GW/cm2 is a threshold value, across which particle size distribution changed. Laser beam diam. was a more influential parameter than power d. in efficient particle generation. Particle loss during transport from the ablation chamber to the ICPMS was significant for a low carrier gas flow rate of 0.1 L/min, while almost no loss was obsd. for a higher flow rate of 0.26 L/min. The onset of ICPMS intensity time profiles decreased as more large particles were generated. ICPMS intensity data were calibrated with respect to the particle mass entering the ICPMS. Particle entrainment efficiency of the LA-ICPMS system was estd. and is a strong function of laser power d.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXmtlKqsr0%253D&md5=f42c5f2c8a022be14c3c1b4935b4d7d2
  34. 34
    Ohlsson, K. E. A. Uncertainty of blank correction in isotope ratio measurement. Anal. Chem. 2013, 85, 5326– 5329,  DOI: 10.1021/ac4003968
    Google Scholar
    34
    Uncertainty of Blank Correction in Isotope Ratio Measurement
    Ohlsson, K. E. Anders
    Analytical Chemistry (Washington, DC, United States) (2013), 85 (11), 5326-5329CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
    Blank correction for isotope ratio measurement on small amts. of substances is often limited by presence of a blank, with an apparent isotopic compn. different from that of the sample. For isotope ratios, blank correction is commonly performed either by the regression method, which works without the need for estn. of the blank, or by the subtraction method. With the subtraction method, estn. of the amt. and isotope delta of the blank is required, and these ests. could be obtained either by direct, semi-indirect, or indirect measurement. Previously given expressions for the std. uncertainties of indirectly measured blank amts. and blank isotope deltas did not account for covariance between input quantities. A previously published data set was reevaluated, with covariance terms properly included in the calcn. of uncertainties. Covariance effects may yield a significant redn. in uncertainty ests., both for blank quantities and for blank cor. results. For series measurements on a std. material, also the distribution of individual cor. isotope delta values around the av. value was approx. normal, with its std. deviation equal to the estd. std. uncertainty of the cor. values. In most cases, the regression and subtraction methods yield approx. the same blank cor. av. values and uncertainties, regardless of method selected for estn. of blank quantities.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXntFWlt7w%253D&md5=a11f2702f96c7edfe9e85c016bba9a31
  35. 35
    Werner, R. A.; Brand, W. A. Referencing strategies and techniques in stable isotope ratio analysis. Rapid Commun. Mass Spectrom. 2001, 15, 501– 519,  DOI: 10.1002/rcm.258
    Google Scholar
    35
    Referencing strategies and techniques in stable isotope ratio analysis
    Werner, Roland A.; Brand, Willi A.
    Rapid Communications in Mass Spectrometry (2001), 15 (7), 501-519CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)
    A review, with 53 refs., is given on techniques for reliable standardization in carrier gas or online techniques where an accepted protocol for assigning δ-values on an internationally accepted scale was not yet defined. Stable isotope ratios are reported in the literature in terms of a deviation from an international std. (δ-values). The referencing procedures, however, differ from instrument to instrument and are not consistent between measurement facilities. This paper reviews an attempt to unify the strategy for referencing isotopic measurements. In particular, emphasis is given to the importance of identical treatment of sample and ref. material (IT principle), which should guide all isotope ratio detns. and evaluations. The implementation of the principle in the lab., the monitoring of the measurement quality, the status of the international scales and ref. materials and necessary correction procedures are discussed.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXivFOjsb4%253D&md5=957d85e78f0b6184465f04570c673d5d
  36. 36
    Werner, R. A.; Bruch, B. A.; Brand, W. A. ConFlo III - an interface for high precision δ13C and δ15N analysis with an extended dynamic range. Rapid Commun. Mass Spectrom. 1999, 13, 1237– 1241,  DOI: 10.1002/(SICI)1097-0231(19990715)13:13<1237::AID-RCM633>3.0.CO;2-C
    Google Scholar
    36
    ConFlo III - an interface for high precision δ13C and δ15N analysis with an extended dynamic range
    Werner, Roland A.; Bruch, Beate A.; Brand, Willi A.
    Rapid Communications in Mass Spectrometry (1999), 13 (13), 1237-1241CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)
    A newly developed interface coupling a CHN combustion device (elemental analyzer EA) to an isotope ratio mass spectrometer is described and evaluated. The purpose of the device is to extend the dynamic range of δ13C and δ15N anal. from <2 orders of magnitude to >3 orders of magnitude. Carbon isotope ratio measurements of atropine as a model compd. were performed analyzing between 1 μg to 5 mg C with acceptable to excellent precision (0.6 to 0.06 ‰ -notation). The correction due to the blank signal is crit. for sample amts. smaller than 4 μg C. The max. sample wt. is detd. by the combustion capacity of the EA. Larger sample amts. are measured using diln. of a small part of the EA effluent with helium. The diln. mechanism works virtually free of isotope fractionation.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXksVKrt7s%253D&md5=f6d599b78335134daf1a75a379f0296a
  37. 37
    Borisov, O. V.; Mao, X.; Russo, R. E. Effects of crater development on fractionation and signal intensity during laser ablation inductively coupled plasma mass spectrometry. Spectrochim. Acta, Part B 2000, 55, 1693– 1704,  DOI: 10.1016/S0584-8547(00)00272-X
    Google Scholar
    37
    Effects of crater development on fractionation and signal intensity during laser ablation inductively coupled plasma mass spectrometry
    Borisov, Oleg V.; Mao, Xianglei; Russo, Richard E.
    Spectrochimica Acta, Part B: Atomic Spectroscopy (2000), 55B (11), 1693-1704CODEN: SAASBH; ISSN:0584-8547. (Elsevier Science B.V.)
    The effects of crater development on ICP-MS signal intensities and elemental fractionation were presented. Craters formed after repetitive 266-nm Nd/YAG laser ablation with 1.0-mJ pulses had a cone-like shape. The laser ablation rate (ng/s) depended on the laser irradiance (laser pulse energy per unit time and unit area), decreasing as irradiance increased. In contrast, the particle entrainment/transport efficiency did not significantly change with irradiance. As the crater-aspect ratio (depth/diam.) increased above some threshold value of six, the Pb/U elemental ratio departed from the stoichiometric value. However, good stoichiometry of ablated mass could be achieved when exptl. conditions were carefully selected. The exact mechanism of how crater development affects fractionation is not well understood. Actual irradiance was introduced instead of a nominal value. Actual irradiance decreased as the crater deepened due to changes of the effective area, sampled by the laser beam.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXosV2ntr0%253D&md5=5ca41b722adbdb23f3155a7c3ffbcd7e
  38. 38
    Bleiner, D.; Plotnikov, A.; Vogt, C.; Wetzig, K.; Günther, D. Depth profile analysis of various titanium based coatings on steel and tungsten carbide using laser ablation inductively coupled plasma--″time of flight″ mass spectrometry. Fresenius' J. Anal. Chem. 2000, 368, 221– 226,  DOI: 10.1007/s002160000417
    Google Scholar
    38
    Depth profile analysis of various titanium based coatings on steel and tungsten carbide using laser ablation inductively coupled plasma - "time of flight" mass spectrometry
    Bleiner, Davide; Plotnikov, Alexei; Vogt, Carla; Wetzig, Klaus; Gunther, D.
    Fresenius' Journal of Analytical Chemistry (2000), 368 (2-3), 221-226CODEN: FJACES; ISSN:0937-0633. (Springer-Verlag)
    A homogenized 193 nm ArF* laser ablation system coupled to an inductively coupled plasma-Time of Flight-mass spectrometer (LA-ICP-TOFMS) was tested for depth profiling anal. on different single-layer Ti based coatings on steel and W carbides. Laser parameters, such as repetition rate, pulse energy and spatial resoln. were tested to allow optimum depth related calibration curves. The ablation process using a laser repetition rate of 3 Hz, 120 μm crater diam., and 100 mJ output energy, leads to linear calibration curves independent of the drill time or peak area used for calibrating the thickness of the layer. The best depth resoln. obtained (without beam splitter) was 0.20 μm per laser shot. The time resoln. of the ICP-TOFMS of 102 ms integration time per isotope was sufficient for the detn. of the drill time of the laser through the coatings into the matrix with better than 2.6% relative std. deviation (∼7 μm coating thickness, n = 7). Variation of the vol. of the ablation cell was not influencing the depth resoln., which suggests that the depth resoln. is governed by the ablation process. However, the application on the Ti(N,C) based single layer shows the potential of LA-ICP-TOFMS as a complementary technique for fast depth detns. on various coatings in the low to medium μm region.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXmtFGmtbw%253D&md5=c453500ab5eaf8fcd7a65a7032e6a840
  39. 39
    Paul, E. A.; Follett, R. F.; Leavitt, S. W.; Halvorson, A.; Peterson, G. A.; Lyon, D. J. Radiocarbon dating for determination of soil organic matter pool sizes and dynamics. Soil Sci. Soc. Am. J. 1997, 61, 1058– 1067,  DOI: 10.2136/sssaj1997.03615995006100040011x
    Google Scholar
    39
    Radiocarbon dating for determination of soil organic matter pool sizes and dynamics
    Paul, E. A.; Follett, R. F.; Leavitt, S. W.; Halvorson, A.; Peterson, G. A.; Lyon, D. J.
    Soil Science Society of America Journal (1997), 61 (4), 1058-1067CODEN: SSSJD4; ISSN:0361-5995. (Soil Science Society of America)
    The size and turnover rate of the resistant soil org. matter (SOM) fractions were measured by 14C dating and 13C/12C measurements. This involved soils archived in 1948, and recent samples, from a series of long-term sites in the North American Great Plains. A reevaluation of C dates obtained in the 1960s expanded the study scope. The 14C ages of surface soils were modern in some native sites and near modern in the low, moist areas of the landscape. They were much older at the catena summits. The 14C ages were not related to latitude, although this strongly influenced the total SOM content. Cultivation resulted in lower C contents and increased the 14C age by an av. of 900 yr. The 10- to 20-cm depths from both cultivated and native sites were 1200 yr older than the 0- to 10-cm depth. The 90- to 120-cm depth of a cultivated site at 7015 yr before present (BP) was 6000 yr older than the surface. The nonhydrolyzable C of this depth dated 9035 yr BP. The residue of 6 M HCl hydrolysis comprised 23 to 70% of the total soil C and was, on the av., 1500 yr older. The percentage of nonhydrolyzable C and its 14C age anal. identify the amt. and turnover rate of the old resistant soil C.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXlt1Shsb8%253D&md5=519bab0af6bdb74364f107a154360095
  40. 40
    Holz, M.; Zarebanadkouki, M.; Kuzyakov, Y.; Pausch, J.; Carminati, A. Root hairs increase rhizosphere extension and carbon input to soil. Ann. Bot. 2018, 121, 61– 69,  DOI: 10.1093/aob/mcx127
    Google Scholar
    40
    Root hairs increase rhizosphere extension and carbon input to soil
    Holz, Maire; Zarebanadkouki, Mohsen; Kuzyakov, Yakov; Pausch, Johanna; Carminati, Andrea
    Annals of Botany (Oxford, United Kingdom) (2018), 121 (1), 61-69CODEN: ANBOA4; ISSN:1095-8290. (Oxford University Press)
    • Background and Aims Although it is commonly accepted that root exudation enhances plant-microbial interactions in the rhizosphere, exptl. data on the spatial distribution of exudates are scarce. Our hypothesis was that root hairs exude org. substances to enlarge the rhizosphere farther from the root surface. • Methods Barley (Hordeum vulgare 'Pallas' - wild type) and its root-hairless mutant (brb) were grown in rhizoboxes and labeled with 14CO2. A filter paper was placed on the soil surface to capture, image and quantify root exudates. • Key Results Plants with root hairs allocated more carbon (C) to roots (wild type: 13 %; brb: 8 % of assimilated 14C) and to rhizosheaths (wild type: 1.2 %; brb: 0.2 %), while hairless plants allocated more C to shoots (wild type: 65 %; brb: 75 %). Root hairs increased the radial rhizosphere extension three-fold, from 0.5 to 1.5 mm. Total exudation on filter paper was three times greater for wild type plants compared to the hairless mutant. • Conclusion Root hairs increase exudation and spatial rhizosphere extension, which probably enhance rhizosphere interactions and nutrient cycling in larger soil vols. Root hairs may therefore be beneficial to plants under nutrient-limiting conditions. The greater C allocation below ground in the presence of root hairs may addnl. foster C sequestration.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXmt1SrtrY%253D&md5=5f69bc3006385034bcf6a360b8108846

Cited By

ARTICLE SECTIONS
Jump To

This article is cited by 22 publications.

  1. Eva Lippold, Steffen Schlüter, Carsten W. Mueller, Carmen Höschen, Gertraud Harrington, Rüdiger Kilian, Martina I. Gocke, Eva Lehndorff, Robert Mikutta, Doris Vetterlein. Correlative Imaging of the Rhizosphere─A Multimethod Workflow for Targeted Mapping of Chemical Gradients. Environmental Science & Technology 2023, 57 (3) , 1538-1549. https://doi.org/10.1021/acs.est.2c07340
  2. Timothy Vazquez, Colette Taylor, Maverick Knowlton, Sean Williams, Theresa Evans-Nguyen. Enabling Isotope Ratio Measurements on an Ion Trap Mass Spectrometer. Journal of the American Society for Mass Spectrometry 2020, 31 (8) , 1722-1729. https://doi.org/10.1021/jasms.0c00143
  3. Amir H. Ahkami, Odeta Qafoku, Tiina Roose, Quanbing Mou, Yi Lu, Zoe G. Cardon, Yuxin Wu, Chunwei Chou, Joshua B. Fisher, Tamas Varga, Pubudu Handakumbura, Jayde A. Aufrecht, Arunima Bhattacharjee, James J. Moran. Emerging sensing, imaging, and computational technologies to scale nano-to macroscale rhizosphere dynamics – Review and research perspectives. Soil Biology and Biochemistry 2024, 189 , 109253. https://doi.org/10.1016/j.soilbio.2023.109253
  4. Daniel M. Cleary, Timothy J. Linley, Jason M. Kriesel, Andrew Fahrland, James F. Kelly, James J. Moran. Laser Ablation-Capillary Absorption Spectroscopy: A novel approach for high throughput and increased spatial resolution measurements of δ13C in plant-soil systems. Soil Biology and Biochemistry 2023, 187 , 109208. https://doi.org/10.1016/j.soilbio.2023.109208
  5. Chongkai Hao, Ping Du, Jie Ren, Lijuan Hu, Zongpeng Zhang. Halophyte Elymus dahuricus colonization regulates microbial community succession by mediating saline-alkaline and biogenic organic matter in bauxite residue. Science of The Total Environment 2023, 905 , 167140. https://doi.org/10.1016/j.scitotenv.2023.167140
  6. Franziska E. Zahn, Erik Söll, Thomas K. Chapin, Deyi Wang, Sofia I. F. Gomes, Nicole A. Hynson, Johanna Pausch, Gerhard Gebauer. Novel insights into orchid mycorrhiza functioning from stable isotope signatures of fungal pelotons. New Phytologist 2023, 239 (4) , 1449-1463. https://doi.org/10.1111/nph.18991
  7. Wulf Amelung, Nele Meyer, Andrey Rodionov, Claudia Knief, Michaela Aehnelt, Sara L. Bauke, Danh Biesgen, Stefan Dultz, Georg Guggenberger, Maguy Jaber, Erwin Klumpp, Ingrid Kögel-Knabner, Volker Nischwitz, Steffen A. Schweizer, Bei Wu, Kai U. Totsche, Eva Lehndorff. Process sequence of soil aggregate formation disentangled through multi-isotope labelling. Geoderma 2023, 429 , 116226. https://doi.org/10.1016/j.geoderma.2022.116226
  8. Charlotte Védère, Laure Vieublé Gonod, Naoise Nunan, Claire Chenu. Opportunities and limits in imaging microorganisms and their activities in soil microhabitats. Soil Biology and Biochemistry 2022, 174 , 108807. https://doi.org/10.1016/j.soilbio.2022.108807
  9. A. Schnepf, A. Carminati, M. A. Ahmed, M. Ani, P. Benard, J. Bentz, M. Bonkowski, M. Knott, D. Diehl, P. Duddek, E. Kröner, M. Javaux, M. Landl, E. Lehndorff, E. Lippold, A. Lieu, C. W. Mueller, E. Oburger, W. Otten, X. Portell, M. Phalempin, A. Prechtel, R. Schulz, J. Vanderborght, D. Vetterlein. Linking rhizosphere processes across scales: Opinion. Plant and Soil 2022, 478 (1-2) , 5-42. https://doi.org/10.1007/s11104-022-05306-7
  10. James J. Moran, Timothy J. Linley, Camille N. Makarem, James F. Kelly, Eric D. Wilcox Freeburg, Daniel M. Cleary, M. Lizabeth Alexander, Jason M. Kriesel. Spectroscopy-based isotopic (δ13C) analysis for high spatial resolution of carbon exchange in the rhizosphere. Rhizosphere 2022, 23 , 100564. https://doi.org/10.1016/j.rhisph.2022.100564
  11. Xue-Ling Chang, Lingyun Chen, Boning Liu, Sheng-Tao Yang, Haifang Wang, Aoneng Cao, Chunying Chen. Stable isotope labeling of nanomaterials for biosafety evaluation and drug development. Chinese Chemical Letters 2022, 33 (7) , 3303-3314. https://doi.org/10.1016/j.cclet.2022.03.057
  12. Anna S. Wendel, Sara L. Bauke, Wulf Amelung, Claudia Knief. Root-rhizosphere-soil interactions in biopores. Plant and Soil 2022, 475 (1-2) , 253-277. https://doi.org/10.1007/s11104-022-05406-4
  13. Riccardo Finotello, Mohamed Tamaazousti, Jean-Baptiste Sirven. HyperPCA: A powerful tool to extract elemental maps from noisy data obtained in LIBS mapping of materials. Spectrochimica Acta Part B: Atomic Spectroscopy 2022, 192 , 106418. https://doi.org/10.1016/j.sab.2022.106418
  14. Qiuyue Shi, Cheng Fang, Changzhou Yan, Xue-Ling Chang, Xian Zhang, Han Zhang. Visualization of fullerenol nanoparticles distribution in Daphnia magna using Laser Ablation-isotope Ratio Mass (LA-IRMS) and Matrix-assisted Laser Desorption/Ionization Imaging Mass Spectrometry (MALDI-IMS). Ecotoxicology and Environmental Safety 2022, 232 , 113226. https://doi.org/10.1016/j.ecoenv.2022.113226
  15. Peng Yao, Haiyan Ni, Dipayan Paul, Agne Masalaite, Ru-Jin Huang, Harro A.J. Meijer, Ulrike Dusek. An automated method for thermal-optical separation of aerosol organic/elemental carbon for 13C analysis at the sub-μgC level: A comprehensive assessment. Science of The Total Environment 2022, 804 , 150031. https://doi.org/10.1016/j.scitotenv.2021.150031
  16. Tom Guhra, Katharina Stolze, Kai Uwe Totsche. Pathways of biogenically excreted organic matter into soil aggregates. Soil Biology and Biochemistry 2022, 164 , 108483. https://doi.org/10.1016/j.soilbio.2021.108483
  17. Manuel Vergara Sosa, Eva Lehndorff, Andrei Rodionov, Martina Gocke, Alexandra Sandhage-Hofmann, Wulf Amelung. Micro-scale resolution of carbon turnover in soil - Insights from laser ablation isotope ratio mass spectrometry on water-glass embedded aggregates. Soil Biology and Biochemistry 2021, 159 , 108279. https://doi.org/10.1016/j.soilbio.2021.108279
  18. Carsten W. Mueller, Markus Steffens, Henning Buddenbaum. Permafrost soil complexity evaluated by laboratory imaging Vis ‐ NIR spectroscopy. European Journal of Soil Science 2021, 72 (1) , 114-119. https://doi.org/10.1111/ejss.12927
  19. Doris Vetterlein, Andrea Carminati, Ingrid Kögel-Knabner, Gerd Patrick Bienert, Kornelia Smalla, Eva Oburger, Andrea Schnepf, Thomas Banitz, Mika Tapio Tarkka, Steffen Schlüter. Rhizosphere Spatiotemporal Organization–A Key to Rhizosphere Functions. Frontiers in Agronomy 2020, 2 https://doi.org/10.3389/fagro.2020.00008
  20. Han ZHANG, Lai WEI, Xu LIAO, Jia-Ni WANG, Qiu-Yue SHI, Xian ZHANG. In Situ Carbon Stable isotope Analysis of Organic Carbon by Laser Ablation-Isotope Ratio Mass Spectrometry. Chinese Journal of Analytical Chemistry 2020, 48 (6) , 774-779. https://doi.org/10.1016/S1872-2040(20)60028-7
  21. E. Hywel Evans, Jorge Pisonero, Clare M. M. Smith, Rex N. Taylor. Atomic spectrometry update: review of advances in atomic spectrometry and related techniques. Journal of Analytical Atomic Spectrometry 2020, 35 (5) , 830-851. https://doi.org/10.1039/D0JA90015J
  22. Jeffrey R. Bacon, Owen T. Butler, Warren R. L. Cairns, Jennifer M. Cook, Christine M. Davidson, Olga Cavoura, Regina Mertz-Kraus. Atomic spectrometry update – a review of advances in environmental analysis. Journal of Analytical Atomic Spectrometry 2020, 35 (1) , 9-53. https://doi.org/10.1039/C9JA90060H
Download PDF

  • Abstract

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 1

    Figure 1. Setup of the LA-IRMS system starting with a newly constructed low-volume cell. Only the upper part of the cell is the active operating volume for laser ablation (marked in red; more details in the Supporting Information).

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 2

    Figure 2. Impact of loading time in the first cryo-trap on the blank peak area in cells with 3.8 and 0.4 mL active volume (without laser ablation). If the loading time was <7 s, the blank was at the baseline level of the IRMS detector for both cells. The isotopic signature of the blank signal was not affected by the loading time.

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 3

    Figure 3. Discrimination of stable carbon isotopes from different organic matrices by ablation with increasing laser energy.

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 4

    Figure 4. Detection limit of the LA-IRMS system given in C amount (a) for the cell with 3.8 mL active volume and (b) for the cell with 0.4 mL active volume (detected with an acryl plate with known ablated crater volume; see also Supporting Information).

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 5

    Figure 5. Spatially resolved microanalysis of δ13C heterogeneity in a soil microaggregate structure from a cropped Luvisol field of 33% clay (53–250 μm aggregate fraction, 20 μm spot size, 40 shots per ablation). Raw δ13C values shown in red and blank corrected δ13C values, in black.

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 6

    Figure 6. Spatial differences of isotopic signatures inside the root, rhizosphere area, and soil matrix from a Miscanthus root ablated with (a) constant spot size of 30 μm and 30 shot numbers and with (b) variable spot size of 15 μm and 40 shot numbers (white-colored signatures) and spot size of 10 μm and 80 shot numbers (black colored signatures), both performed on a 60 μm cross section; in-house reference acryl = −29.75 ± 0.04‰.

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 7

    Figure 7. Spatial differences of isotopic signatures ablated from 2 mm sieved soil with constant spot size of 10 μm and 60 shot numbers after 2 years of C3 to C4 vegetation change (Zea mais L., Selhausen; in-house reference acryl = −29.57 ± 0.32‰).

    High Resolution Image
    Download MS PowerPoint Slide

  • References

    ARTICLE SECTIONS
    Jump To

    This article references 40 other publications.

    1. 1
      Köhler, P. Using the Suess effect on the stabile carbon isotope to distinguish the future from the past in radiocarbon. Environ. Res. Lett. 2016, 11, 124016,  DOI: 10.1088/1748-9326/11/12/124016
      Google Scholar
      There is no corresponding record for this reference.
    2. 2
      Beer, K. D.; Orellana, M. V.; Baliga, N. S. Modeling the evolution of C4 photosynthesis. Cell 2013, 153, 1427– 1429,  DOI: 10.1016/j.cell.2013.05.058
      Google Scholar
      2
      Modeling the evolution of C4 photosynthesis
      Beer, Karlyn D.; Orellana, Monica V.; Baliga, Nitin S.
      Cell (Cambridge, MA, United States) (2013), 153 (7), 1427-1429CODEN: CELLB5; ISSN:0092-8674. (Cell Press)
      FR OLa review. The prediction and verification of adaptive trajectories on macroevolutionary timescales have rarely been achieved for complex biol. systems. Employing a model linking biol. information at multiple scales, Heckmann et al. simulate likely sequences of evolutionary changes from C3 to C4 photosynthesis biochem.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtVWgt7rE&md5=81b2efe1c68a72c7fc39be37ead18569
    3. 3
      Kellogg, E. A. C4 photosynthesis. Curr. Biol. 2013, 23, R594– 9,  DOI: 10.1016/j.cub.2013.04.066
      Google Scholar
      3
      C4 photosynthesis
      Kellogg, Elizabeth A.
      Current Biology (2013), 23 (14), R594-R599CODEN: CUBLE2; ISSN:0960-9822. (Cell Press)
      A review. The no. of humans on earth is increasing, generating concerns about food security and spurring efforts throughout the world to increase the productivity of crops. If a way could be found to increase the yield of crops by, say, 20%, it would have immense impact on global food supplies. Fortunately, evolution has already crafted such a mechanism, known as C4 photosynthesis. The C4 pathway is in effect a turbocharger for the more conventional C3 pathway. Just as a turbocharger improves performance of an engine by forcing more air into the manifold, C4 improves photosynthetic performance by forcing CO2 into the std. C3 photosynthetic app. The added efficiency of this mechanism is obvious at a global level. Only about 3% of flowering plant species use the C4 pathway, but this relative handful of species account for 23% of the carbon fixed (primary productivity) in the world. The pathway occurs in several of the world's major crops, notably maize (corn) and sorghum, and in many of the species in use as biofuels, most importantly sugar cane; all of these are grasses in the family Poaceae. If a major C3 crop such as rice could be bred to use the C4 pathway, the economic impact would be immense.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtFCqtr7E&md5=8b4f50068ca8f7db76f0f597fc4c4ebc
    4. 4
      Moreno-Gutiérrez, C.; Dawson, T. E.; Nicolás, E.; Querejeta, J. I. Isotopes reveal contrasting water use strategies among coexisting plant species in a Mediterranean ecosystem. New Phytol. 2012, 196, 489– 496,  DOI: 10.1111/j.1469-8137.2012.04276.x
      Google Scholar
      4
      Isotopes reveal contrasting water use strategies among coexisting plant species in a Mediterranean ecosystem
      Moreno-Gutierrez, Cristina; Dawson, Todd E.; Nicolas, Emilio; Querejeta, Jose Ignacio
      New Phytologist (2012), 196 (2), 489-496CODEN: NEPHAV; ISSN:0028-646X. (Wiley-Blackwell)
      Summary : Variation in the stable carbon and oxygen isotope compn. (δ13C, Δ18O) of co-occurring plant species may reflect the functional diversity of water use strategies present in natural plant communities. We investigated the patterns of water use among 10 coexisting plant species representing diverse taxonomic groups and life forms in semiarid southeast Spain by measuring their leaf δ13C and Δ18O, the oxygen isotope ratio of stem water and leaf gas exchange rates. Across species, Δ18O was tightly neg. correlated with stomatal conductance (gs), whereas δ13C was pos. correlated with intrinsic water use efficiency (WUEi). Broad interspecific variation in Δ18O, δ13C and WUEi was largely detd. by differences in gs, as indicated by a strong pos. correlation between leaf δ13C and Δ18O across species. The 10 co-occurring species segregated along a continuous ecophysiol. gradient defined by their leaf δ13C and Δ18O, thus revealing a wide spectrum of stomatal regulation intensity and contrasting water use strategies ranging from profligate/opportunistic' (high gs, low WUEi) to conservative' (low gs, high WUEi). Coexisting species maintained their relative isotopic rankings in 2 yr with contrasting rainfall, suggesting the existence of species-specific isotopic niches' that reflect ecophysiol. niche segregation in dryland plant communities.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtlGjt77P&md5=a0241ffcb2f7936250cf6cf935d37c38
    5. 5
      Gebrekirstos, A.; van Noordwijk, M.; Neufeldt, H.; Mitlöhner, R. Relationships of stable carbon isotopes, plant water potential and growth: an approach to asses water use efficiency and growth strategies of dry land agroforestry species. Trees 2011, 25, 95– 102,  DOI: 10.1007/s00468-010-0467-0
      Google Scholar
      There is no corresponding record for this reference.
    6. 6
      Hartman, G.; Danin, A. Isotopic values of plants in relation to water availability in the Eastern Mediterranean region. Oecologia 2010, 162, 837– 852,  DOI: 10.1007/s00442-009-1514-7
      Google Scholar
      6
      Isotopic values of plants in relation to water availability in the Eastern Mediterranean region
      Hartman Gideon; Danin Avinoam
      Oecologia (2010), 162 (4), 837-52 ISSN:.
      Plant C and N isotope values often correlate with rainfall on global and regional scales. This study examines the relationship between plant isotopic values and rainfall in the Eastern Mediterranean region. The results indicate significant correlations between both C and N isotope values and rainfall in C(3) plant communities. This significant relationship is maintained when plant communities are divided by plant life forms. Furthermore, a seasonal increase in C isotope values is observed during the dry season while N isotope values remain stable across the wet and dry seasons. Finally, the isotopic pattern in plants originating from desert environments differs from those from Mediterranean environments because some desert plants obtain most of their water from secondary sources, namely water channeled by local topographic features rather than direct rainfall. From these results it can be concluded that water availability is the primary factor controlling C and N isotope variability in plant communities in the Eastern Mediterranean.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC3c7ovFyjug%253D%253D&md5=a6724a1e128bbb1f782cc1355a0708d2
    7. 7
      Hudson, A. M.; Quade, J.; Ali, G.; Boyle, D.; Bassett, S.; Huntington, K. W.; De los Santos, M. G.; Cohen, A. S.; Lin, K.; Wang, X. Stable C, O and clumped isotope systematics and 14C geochronology of carbonates from the Quaternary Chewaucan closed-basin lake system, Great Basin, USA: Implications for paleoenvironmental reconstructions using carbonates. Geochim. Cosmochim. Ac. 2017, 212, 274– 302,  DOI: 10.1016/j.gca.2017.06.024
      Google Scholar
      There is no corresponding record for this reference.
    8. 8
      Wilson, K. E.; Maslin, M. A.; Leng, M. J.; Kingston, J. D.; Deino, A. L.; Edgar, R. K.; Mackay, A. W. East African lake evidence for Pliocene millennial-scale climate variability. Geology 2014, 42, 955– 958,  DOI: 10.1130/G35915.1
      Google Scholar
      There is no corresponding record for this reference.
    9. 9
      Laskov, C.; Amelung, W.; Peiffer, S. Organic Matter Preservation in the Sediment of an Acidic Mining Lake. Environ. Sci. Technol. 2002, 36, 4218– 4223,  DOI: 10.1021/es010320y
      Google Scholar
      9
      Organic Matter Preservation in the Sediment of an Acidic Mining Lake
      Laskov, Christine; Amelung, Wulf; Peiffer, Stefan
      Environmental Science and Technology (2002), 36 (20), 4218-4223CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
      Sustainable management of acidic mining lakes requires knowledge of the origin and reactivity of its sedimentary org. matter. We identified different pools of org. matter (OM) in the Fe-rich sediment (up to 35%) of an acidic (pH 2.8) mining lake using δ13C-signals, C/N ratios, and the markers alkanes, lignin-derived phenols, and benzenepolycarboxylic acids (BPCAs). Addnl., a d. fractionation was applied to each sediment layer. Three fractions, aquatic (AOM), terrestrial (TOM), and lignite-derived (LOM) org. matter, were discriminated, of which AOM composes only a small fraction, with a min. at the sediment bottom. The terrestrial contribution to sedimentary OM is higher than that of AOM but still low throughout the sediment core, whereas lignite-derived OM constitutes the major carbon fraction, even in the upper sediment layers. The size of the carbon pools was quantified with a mass-balance approach, in which the BPCA content was utilized as an est. for the lignite fraction in combination with the δ13C-signals of the three C fractions. The largest amt. of OM was found in the heaviest (>2.4 g/cm3) of the three d. fractions of the two upper sediment layers, which implies strong interaction with iron hydroxides. Comparisons with carbon oxidn. rates revealed that besides the refractory origin of the OM, sorptive preservation by solid iron phases controls carbon reactivity in the sediment and, hence, the internal neutralization capacity of the lake system.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XmvFKrsrc%253D&md5=84c7c5e76a561d35d2f1f8f9f78027fa
    10. 10
      Derrien, D.; Amelung, W. Computing the mean residence time of soil carbon fractions using stable isotopes: impacts of the model framework. Europ. J. Soil Sci. 2011, 62, 237– 252,  DOI: 10.1111/j.1365-2389.2010.01333.x
      Google Scholar
      There is no corresponding record for this reference.
    11. 11
      Still, C. J.; Berry, J. A.; Collatz, G. J.; DeFries, R. S. Global distribution of C 3 and C 4 vegetation: Carbon cycle implications. Global Biogeochem. Cycles 2003, 17, 6-1– 6-14,  DOI: 10.1029/2001GB001807
      Google Scholar
      There is no corresponding record for this reference.
    12. 12
      Blagodatskaya, E.; Yuyukina, T.; Blagodatsky, S.; Kuzyakov, Y. Turnover of soil organic matter and of microbial biomass under C3–C4 vegetation change: Consideration of 13C fractionation and preferential substrate utilization. Soil Biol. Biochem. 2011, 43, 159– 166,  DOI: 10.1016/j.soilbio.2010.09.028
      Google Scholar
      12
      Turnover of soil organic matter and of microbial biomass under C3-C4 vegetation change: Consideration of 13C fractionation and preferential substrate utilization
      Blagodatskaya, E.; Yuyukina, T.; Blagodatsky, S.; Kuzyakov, Y.
      Soil Biology & Biochemistry (2011), 43 (1), 159-166CODEN: SBIOAH; ISSN:0038-0717. (Elsevier B.V.)
      Two processes contribute to changes of the δ13C signature in soil pools: 13C fractionation per se and preferential microbial utilization of various substrates with different δ13C signature. These two processes were disentangled by simultaneously tracking δ13C in three pools - soil org. matter (SOM), microbial biomass, dissolved org. carbon (DOC) - and in CO2 efflux during incubation of (1) soil after C3-C4 vegetation change, and (2) the ref. C3 soil. The study was done on the Ap horizon of a loamy Gleyic Cambisol developed under C3 vegetation. Miscanthus giganteus - a perennial C4 plant - was grown for 12 years, and the δ13C signature was used to distinguish between old' SOM (>12 years) and recent'Miscanthus-derived C (<12 years). The differences in δ13C signature of the three C pools and of CO2 in the ref. C3 soil were less than 1‰, and only δ13C of microbial biomass was significantly different compared to other pools. Nontheless, the neglecting of isotopic fractionation can cause up to 10% of errors in calcns. In contrast to the ref. soil, the δ13C of all pools in the soil after C3-C4 vegetation change was significantly different. Old C contributed only 20% to the microbial biomass but 60% to CO2. This indicates that most of the old C was decompd. by microorganisms catabolically, without being utilized for growth. Based on δ13C changes in DOC, CO2 and microbial biomass during 54 days of incubation in Miscanthus and ref. soils, we concluded that the main process contributing to changes of the δ13C signature in soil pools was preferential utilization of recent vs. old C (causing an up to 9.1‰ shift in δ13C values) and not 13C fractionation per se. Based on the δ13C changes in SOM, we showed that the estd. turnover time of old SOM increased by two years per yr in 9 years after the vegetation change. The relative increase in the turnover rate of recent microbial C was 3 times faster than that of old C indicating preferential utilization of available recent C vs. the old C. Combining long-term field observations with soil incubation reveals that the turnover time of C in microbial biomass was 200 times faster than in total SOM. Our study clearly showed that estg. the residence time of easily degradable microbial compds. and biomarkers should be done at time scales reflecting microbial turnover times (days) and not those of bulk SOM turnover (years and decades). This is necessary because the absence of C reutilization is a prerequisite for correct estn. of SOM turnover. We conclude that comparing the δ13C signature of linked pools helps calc. the relative turnover of old and recent pools.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhsVGrs7zJ&md5=661f5b3001db53a25bc355f2611a7745
    13. 13
      Schemmel, F.; Mikes, T.; Rojay, B.; Mulch, A. The impact of topography on isotopes in precipitation across the Central Anatolian Plateau (Turkey). Am. J. Sci. 2013, 313, 61– 80,  DOI: 10.2475/02.2013.01
      Google Scholar
      13
      The impact of topography on isotopes in precipitation across the Central Anatolian Plateau (Turkey)
      Schemmel, Fabian; Mikes, Tamas; Rojay, Bora; Mulch, Andreas
      American Journal of Science (2013), 313 (2), 61-80CODEN: AJSCAP; ISSN:0002-9599. (Kline Geology Laboratory)
      Paleoelevation reconstructions of mountain belts and orogenic plateaus based on stable isotope climate and pptn. records benefit greatly from present-day calibrations that relate the fractionation of hydrogen (δD) and oxygen (δ18O) isotopes in pptn. to orog. rainfall. Here, we establish a first-order template of δD and δ18O of modern meteoric waters across the Central Anatolian Plateau (CAP) and its bordering Pontic and Taurus Mountains. We identify key regions in the plateau interior and along the plateau margins that have the potential to reliably record topog.-related paleotemperature and paleopptn. changes as recovered from stable isotope paleosol, fossil teeth or lipid proxy data. Based on δD and δ18O data of more than 480 surface water samples from small catchments and springs, we characterize moisture sources affecting the net isotopic budget of pptn. over the CAP and analyze how orog. rainout and plateau aridity shape modem patterns of δD and δ18O in pptn. The Taurus Mountains bordering the CAP to the south act as a major orog. barrier for transport of predominantly winter moisture and exhibit isotopic lapse rates of approx. -20‰/km for δD and -2.9‰/km for δ18O across an elevation range of nearly 3000 m. The Pontic Mountains at the northern margin of the CAP force perennial moisture to ascend and condensate revealing lapse rates of -19‰/km for δD and -2.6‰/km for δ18O. The difference in the predominant moisture source for the southern and northern margins of the CAP (North African vs. Atlantic air masses) is manifested in systematic north-south differences in near-sea level meteoric water compns. of Δ(δDN-S) ∼20 permil and Δ(δ18ON-S) ∼3 permil in a swath across the central part of the plateau. Stable isotope data from the semi-arid plateau interior with rainfall as low as 300 to 500 mm/yr and mean summer temps. attaining 23 °C, provide clear evidence for an evaporative regime that drastically affects surface water and runoff compns. and results in a local meteoric water line for the plateau interior that follows δD = 4.0 · δ18O - 29.3. Strongly evaporitic conditions contrast rainfall patterns along the plateau margins including their immediate leeward flanks where δD- and δ18O-elevation relationships are reliable predictors of modern topog.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXms1Ggtr8%253D&md5=be3863c72d7eebbc5b93015fc8b595e6
    14. 14
      Leier, A.; Quade, J.; DeCelles, P.; Kapp, P. Stable isotopic results from paleosol carbonate in South Asia: Paleoenvironmental reconstructions and selective alteration. Earth Planet. Sci. Lett. 2009, 279, 242– 254,  DOI: 10.1016/j.epsl.2008.12.044
      Google Scholar
      14
      Stable isotopic results from paleosol carbonate in South Asia: Paleoenvironmental reconstructions and selective alteration
      Leier, Andrew; Quade, Jay; DeCelles, P.; Kapp, P.
      Earth and Planetary Science Letters (2009), 279 (3-4), 242-254CODEN: EPSLA2; ISSN:0012-821X. (Elsevier B.V.)
      We measured δ18O and δ13C values of paleosol carbonate nodules from a variety of sedimentary units in southern Asia in order to reconstruct paleoenvironmental conditions and to evaluate for possible diagenetic alteration. Paleosol carbonate nodules were collected from Lower to Upper Cretaceous strata exposed in two locations in southern Tibet, and from Lower to Middle Miocene strata in northern India and Nepal. Addnl. samples were collected from stratigraphically adjacent marine carbonate units to test for possible resetting of stable isotope values. Based on the implausibly low δ18O values (∼ - 13‰) of most of the marine carbonate samples, we interpret the δ18O values of the assocd. paleosol carbonate nodules as being reset, and therefore unreliable for paleoenvironmental or paleoelevation reconstruction. Importantly, the δ18O values of both marine and nonmarine carbonate samples have been altered irresp. of texture, including micritic fabrics, suggesting textural criteria alone are insufficient to det. whether primary stable isotope values have been altered. In contrast, δ13C values of marine carbonate rocks fall within the expected primary isotopic range, and so by assocn. we interpret the δ13C values of paleosol carbonate from the same sections to have been unaffected by diagenesis. Using the δ13C values of paleosol carbonate nodules from Cretaceous strata in southern Tibet, atm. pCO2 is estd. to have been 1400-2000 ppmV between 130-120 Ma, and 2600-3200 ppmV between 100-90 Ma, consistent with previous ests. of pCO2 for these time periods. Paleosol carbonate nodules within early to middle Miocene strata in northern India and Nepal have av. δ13C values of -10.4‰, indicating virtually pure C3 vegetation and lower pCO2.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXisFaisr8%253D&md5=038157475bc9f6f843ed45f071819a8a
    15. 15
      Sikes, N. E.; Ashley, G. M. Stable isotopes of pedogenic carbonates as indicators of paleoecology in the Plio-Pleistocene (upper Bed I), western margin of the Olduvai Basin, Tanzania. J. Hum. Evol. 2007, 53, 574– 594,  DOI: 10.1016/j.jhevol.2006.12.008
      Google Scholar
      15
      Stable isotopes of pedogenic carbonates as indicators of paleoecology in the Plio-Pleistocene (upper Bed I), western margin of the Olduvai Basin, Tanzania
      Sikes Nancy E; Ashley Gail M
      Journal of human evolution (2007), 53 (5), 574-94 ISSN:0047-2484.
      Paleosol carbonates from trenches excavated as part of a landscape-scale project in Bed I of Olduvai Gorge, Tanzania, were analyzed for stable carbon and oxygen isotopic composition. The approximately 60,000-year interval ( approximately 1.845-1.785 Ma) above Tuff IB records evidence for lake and fluvial sequences, volcanic eruptions, eolian and pedogenic processes, and the development of a fluvial plain in the western margin of the basin. Significant temporal variation in the carbonate delta(18)O values records variation of local precipitation and supports the shifts in climatic conditions interpreted from the lithologic record. During this period, carbonate delta(13)C values varied between depositional facies indicating that the paleolandscape supported a local biomass of about 40-60% C(4) plants within a mosaic of grassy woodlands and wooded grasslands. The lithologic and stable isotope record in this small lake basin indicates the area was much wetter, with more woody C(3) plants, during this interval than is the semi-arid area today. The record also reflects the variation in climatic conditions (wet/dry) documented by other global climate proxies for this time.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD1czjs1aisg%253D%253D&md5=cfe518ba380657bd3e903329297b8894
    16. 16
      Sankaran, M.; Hanan, N. P.; Scholes, R. J.; Ratnam, J.; Augustine, D. J.; Cade, B. S.; Gignoux, J.; Higgins, S. I.; Le Roux, X.; Ludwig, F.; Ardo, J.; Banyikwa, F.; Bronn, A.; Bucini, G.; Caylor, K. K.; Coughenour, M. B.; Diouf, A.; Ekaya, W.; Feral, C. J.; February, E. C.; Frost, P. G. H.; Hiernaux, P.; Hrabar, H.; Metzger, K. L.; Prins, H. H. T.; Ringrose, S.; Sea, W.; Tews, J.; Worden, J.; Zambatis, N. Determinants of woody cover in African savannas. Nature 2005, 438, 846– 849,  DOI: 10.1038/nature04070
      Google Scholar
      16
      Determinants of woody cover in African savannas
      Sankaran, Mahesh; Hanan, Niall P.; Scholes, Robert J.; Ratnam, Jayashree; Augustine, David J.; Cade, Brian S.; Gignoux, Jacques; Higgins, Steven I.; Le Roux, Xavier; Ludwig, Fulco; Ardo, Jonas; Banyikwa, Feetham; Bronn, Andries; Bucini, Gabriela; Caylor, Kelly K.; Coughenour, Michael B.; Diouf, Alioune; Ekaya, Wellington; Feral, Christie J.; February, Edmund C.; Frost, Peter G. H.; Hiernaux, Pierre; Hrabar, Halszka; Metzger, Kristine L.; Prins, Herbert H. T.; Ringrose, Susan; Sea, William; Tews, Joerg; Worden, Jeff; Zambatis, Nick
      Nature (London, United Kingdom) (2005), 438 (7069), 846-849CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)
      Savannas are globally important ecosystems of great significance to human economies. In these biomes, which are characterized by the co-dominance of trees and grasses, woody cover is a chief determinant of ecosystem properties. The availability of resources (water, nutrients) and disturbance regimes (fire, herbivory) are thought to be important in regulating woody cover, but perceptions differ on which of these are the primary drivers of savanna structure. Here we show, using data from 854 sites across Africa, that max. woody cover in savannas receiving a mean annual pptn. (MAP) of less than ∼650 mm is constrained by, and increases linearly with, MAP. These arid and semi-arid savannas may be considered 'stable' systems in which water constrains woody cover and permits grasses to coexist, while fire, herbivory and soil properties interact to reduce woody cover below the MAP-controlled upper bound. Above a MAP of ∼650 mm, savannas are 'unstable' systems in which MAP is sufficient for woody canopy closure, and disturbances (fire, herbivory) are required for the coexistence of trees and grass. These results provide insights into the nature of African savannas and suggest that future changes in pptn. may considerably affect their distribution and dynamics.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXht1ynsrrP&md5=9d8498bc8f611c5b9f0922e214978f74
    17. 17
      van Malderen, S. J. M.; Laforce, B.; van Acker, T.; Vincze, L.; Vanhaecke, F. Imaging the 3D trace metal and metalloid distribution in mature wheat and rye grains via laser ablation-ICP-mass spectrometry and micro-X-ray fluorescence spectrometry. J. Anal. At. Spectrom. 2017, 32, 289– 298,  DOI: 10.1039/C6JA00357E
      Google Scholar
      17
      Imaging the 3D trace metal and metalloid distribution in mature wheat and rye grains via laser ablation-ICP-mass spectrometry and micro-X-ray fluorescence spectrometry
      Van Malderen, Stijn J. M.; Laforce, Brecht; Van Acker, Thibaut; Vincze, Laszlo; Vanhaecke, Frank
      Journal of Analytical Atomic Spectrometry (2017), 32 (2), 289-298CODEN: JASPE2; ISSN:0267-9477. (Royal Society of Chemistry)
      Toxic trace metals and metalloids in human nutrient sources pose a severe health risk, and the processes governing metal accumulation should hence be well understood. In this work, the spatial distribution of toxic trace metals/metalloids and micronutrients (Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb) in mature wheat (Triticum aestivum L.) and rye (Secale cereale L.) grains at typical exposure levels was visualized and quantified via laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) by serial sectioning. The bulk concns. of these elements were also detd. by pneumatic nebulisation-ICP-MS. Furthermore, longitudinal sections were scanned using μ-X-ray fluorescence spectrometry to confirm the major element distribution. Serial sectioning in this study was realized via a polishing strategy. Although the methodol. is time-consuming and laborious, it enables to access 3D information for samples which cannot be sectioned using a microtome on a depth scale that would otherwise be inaccessible by a laser probe. In the elemental images, strong local enrichment patterns for Mn and Zn are apparent in the aleurone layer/seed coat, vascular tissue of the crease, and embryonic tissue, whereas Cr, As, Cd and Pb have been mainly accumulated in the grain endosperm as a result of different transport and storage dynamics.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvF2gurnO&md5=5c71ba8d42e15ae6d83a01f96b6723ce
    18. 18
      van Malderen, S. J. M.; Vergucht, E.; De Rijcke, M.; Janssen, C.; Vincze, L.; Vanhaecke, F. Quantitative Determination and Subcellular Imaging of Cu in Single Cells via Laser Ablation-ICP-Mass Spectrometry Using High-Density Microarray Gelatin Standards. Anal. Chem. 2016, 88, 5783– 5789,  DOI: 10.1021/acs.analchem.6b00334
      Google Scholar
      18
      Quantitative Determination and Subcellular Imaging of Cu in Single Cells via Laser Ablation-ICP-Mass Spectrometry Using High-Density Microarray Gelatin Standards
      Van Malderen, Stijn J. M.; Vergucht, Eva; De Rijcke, Maarten; Janssen, Colin; Vincze, Laszlo; Vanhaecke, Frank
      Analytical Chemistry (Washington, DC, United States) (2016), 88 (11), 5783-5789CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
      This manuscript describes the development and characterization of a high-d. microarray calibration std., manufd. inhouse and designed to overcome the limitations in precision, accuracy, and throughput of current calibration approaches for the quantification of elemental concns. on the cellular level using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS). As a case study, the accumulation of Cu in the model organism Scrippsiella trochoidea resulting from transition metal exposure (ranging from 0.5 to 100 μg/L) was evaluated. After the Cu exposure, cells of this photosynthetic dinoflagellate were treated with a crit. point drying protocol, transferred to a carbon stub, and sputter-coated with a Au layer for SEM (SEM) anal. In subsequent LA-ICPMS anal., approx. 100 cells of each population were individually ablated. This approach permitted the evaluation of the mean concn. of Cu in the cell population across different exposure levels and also allowed the examn. of the cellular distribution of Cu within the populations. In a cross-validation exercise, subcellular LA-ICPMS imaging was demonstrated to corroborate synchrotron radiation confocal X-ray fluorescence (SR-XRF) microimaging of single cells investigated under in vivo conditions.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xnt12rsrY%253D&md5=4e6b5d9cf4155b2114dad93e6ed3ed5d
    19. 19
      Wu, B.; Becker, J. S. Imaging of elements and molecules in biological tissues and cells in the low-micrometer and nanometer range. Int. J. Mass Spectrom. 2011, 307, 112– 122,  DOI: 10.1016/j.ijms.2011.01.019
      Google Scholar
      19
      Imaging of elements and molecules in biological tissues and cells in the low-micrometer and nanometer range
      Wu, Bei; Becker, J. Sabine
      International Journal of Mass Spectrometry (2011), 307 (1-3), 112-122CODEN: IMSPF8; ISSN:1387-3806. (Elsevier B.V.)
      A review. Investigation of small areas of biol. tissues or single cells is of particular interest in the life sciences. Chem. imaging in such samples is able to provide the spatial distribution as well as concns. of elements and mols. present in the sample. At present, the anal. techniques supporting chem. imaging are under intensive development with respect to higher spatial resoln. and higher sensitivity and accuracy. In this review, we will focus on the state of the art of advanced mass spectrometric techniques such as secondary ionization mass spectrometry (SIMS), imaging matrix-assisted laser desorption/ionization mass spectrometry (imaging MALDI-MS), nano-scale laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) vs. non-mass spectrometric techniques, for instance, synchrotron-based X-ray fluorescence and scanning near-field optical microscopy (SNOM) assist Raman spectroscopy, with lateral resoln. down to low-micrometer and nanometer scales. The outstanding features and drawbacks of each technique are also discussed regarding their application on the study of biol. samples. The promising future of imaging mass spectrometric techniques, esp. nano-scale LA-ICP-MS, for application in biochem. studies with high spatial resoln. down to the nanometer range is also discussed.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXht1WktLrE&md5=4eaf89abc0fe321da3fd938ced7705d3
    20. 20
      Limbeck, A.; Galler, P.; Bonta, M.; Bauer, G.; Nischkauer, W.; Vanhaecke, F. Recent advances in quantitative LA-ICP-MS analysis: challenges and solutions in the life sciences and environmental chemistry. Anal. Bioanal. Chem. 2015, 407, 6593– 6617,  DOI: 10.1007/s00216-015-8858-0
      Google Scholar
      20
      Recent advances in quantitative LA-ICP-MS analysis: challenges and solutions in the life sciences and environmental chemistry
      Limbeck, Andreas; Galler, Patrick; Bonta, Maximilian; Bauer, Gerald; Nischkauer, Winfried; Vanhaecke, Frank
      Analytical and Bioanalytical Chemistry (2015), 407 (22), 6593-6617CODEN: ABCNBP; ISSN:1618-2642. (Springer)
      A review. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is a widely accepted method for direct sampling of solid materials for trace elemental anal. The no. of reported applications is high and the application range is broad; besides geochem., LA-ICP-MS is mostly used in environmental chem. and the life sciences. This review focuses on the application of LA-ICP-MS for quantification of trace elements in environmental, biol., and medical samples. The fundamental problems of LA-ICP-MS, such as sample-dependent ablation behavior and elemental fractionation, can be even more pronounced in environmental and life science applications as a result of the large variety of sample types and conditions. Besides variations in compn., the range of available sample states is highly diverse, including powders (e.g., soil samples, fly ash), hard tissues (e.g., bones, teeth), soft tissues (e.g., plants, tissue thin-cuts), or liq. samples (e.g., whole blood). Within this article, quantification approaches that have been proposed in the past are critically discussed and compared regarding the results obtained in the applications described. Although a large variety of sample types is discussed within this article, the quantification approaches used are similar for many anal. questions and have only been adapted to the specific questions. Nevertheless, none of them proved to be a universally applicable method.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFOisr%252FI&md5=fbc1838ed42ad908fae0b174797a477b
    21. 21
      Scarciglia, F.; Barca, D.; De Rosa, R.; Pulice, I. Application of laser ablation ICP-MS and traditional micromorphological techniques to the study of an Alfisol (Sardinia, Italy) in thin sections: Insights into trace element distribution. Geoderma 2009, 152, 113– 126,  DOI: 10.1016/j.geoderma.2009.05.021
      Google Scholar
      21
      Application of laser ablation ICP-MS and traditional micromorphological techniques to the study of an Alfisol (Sardinia, Italy) in thin sections: Insights into trace element distribution
      Scarciglia, Fabio; Barca, Donatella; De Rosa, Rosanna; Pulice, Iolanda
      Geoderma (2009), 152 (1-2), 113-126CODEN: GEDMAB; ISSN:0016-7061. (Elsevier B.V.)
      An innovative methodol. approach is proposed in this study, based on the chem. anal. of different portions of soil horizons (illuvial pedofeatures, pedogenic matrix and skeletal parent rock fragments) by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), assocd. with traditional micromorphol. (optical and SEM) techniques. Validation of the LA-ICP-MS technique provides in situ accurate and reproducible (RSD 13-18%) anal. of low concn. trace elements and rare earth elements (REE) in soil samples (0.001-0.1 ppm). Analyses were carried out on thin sections prepd. from undisturbed soil samples, collected from three different Bt (argillic, i.e. clay-illuviated) horizons in an Alfisol from the Muravera area (southeastern Sardinia, Italy). The main aims were (i) to develop and test the reliability of a LA-ICP-MS anal. method on soil thin sections and (ii) to explore the idea that concns. of trace and rare earth elements in the different portions of a soil profile can be used to investigate their distribution, as a response to pedogenetic processes. The three horizons show similar features, particularly in terms of element concns. and patterns. By comparing the concn. of REE and other trace elements in the clay coatings, the soil matrix and the skeletal rock fragments in the same horizon, a general enrichment trend is obsd. from the parent rock to the pedogenic matrix up to the illuvial pedofeatures, suggesting a prominent role of pedogenetic processes in element fractionation and distribution during weathering. In particular, the highest concn. of trace elements (and specifically REE) in clay coatings, which represent the most mobile solid phase in the soil profile, indicates that the former can be used as a reliable indicator of soil weathering if a preliminary assessment of the presence of clay coatings is achieved. In addn., the discontinuous trend of some trace elements among soil features of different horizons is consistent with field evidence of slope dynamics, marked by an erosive and depositional discontinuity along the soil profile.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXptFGnt7s%253D&md5=31a3c8c902bb4456f46ae618425bbd17
    22. 22
      Spötl, C.; Mattey, D. Stable isotope microsampling of speleothems for palaeoenvironmental studies: A comparison of microdrill, micromill and laser ablation techniques. Chem. Geol. 2006, 235, 48– 58,  DOI: 10.1016/j.chemgeo.2006.06.003
      Google Scholar
      There is no corresponding record for this reference.
    23. 23
      Bruneau, P. M. C.; Ostle, N.; Davidson, D. A.; Grieve, I. C.; Fallick, A. E. Determination of rhizosphere 13C pulse signals in soil thin sections by laser ablation isotope ratio mass spectrometry. Rapid Commun. Mass Spectrom. 2002, 16, 2190– 2194,  DOI: 10.1002/rcm.740
      Google Scholar
      23
      Determination of rhizosphere 13C pulse signals in soil thin sections by laser ablation isotope ratio mass spectrometry
      Bruneau, Patricia M. C.; Ostle, Nick; Davidson, Donald A.; Grieve, Ian C.; Fallick, Anthony E.
      Rapid Communications in Mass Spectrometry (2002), 16 (23), 2190-2194CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)
      In grassland ecosystems, soil animals act as key soil engineers and architects. The diversity of soil animals is also a regulator of ecosystem carbon flow. However, our understanding of the link between soil animals, carbon fluxes and soil phys. organization remains poor. An integrated approach based on soil micromorphol. and laser ablation stable isotope ratio mass spectrometry (LA-IRMS) was developed to provide spatially distributed data of pulse-derived 13C trace from roots in the soil environment. This paper describes the development and testing of a LA-IRMS 13C/12C anal. method on soil thin sections as a means to det. the fate of root carbon derived from photosynthesis into soil. Results from this work demonstrated (1) that microscale δ13C (‰) anal. could be made on targeted features located within a soil thin section and (2) that LA-IRMS δ13C (‰) measurements made on samples obtained from 13CO2 pulse labeled plant-soil blocks confirmed the presence of recent photosynthates in the rhizosphere (1 and 4 wk post-pulse).
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XptlGrsr0%253D&md5=79393089eb989c96be41549b4f82853b
    24. 24
      Schulze, B.; Wirth, C.; Linke, P.; Brand, W. A.; Kuhlmann, I.; Horna, V.; Schulze, E.-D. Laser ablation-combustion-GC-IRMS--a new method for online analysis of intra-annual variation of delta13C in tree rings. Tree Physiol. 2004, 24, 1193– 1201,  DOI: 10.1093/treephys/24.11.1193
      Google Scholar
      24
      Laser ablation-combustion-GC-IRMS - a new method for online analysis of intra-annual variation of δ13C in tree rings
      Schulze, Birgit; Wirth, Christian; Linke, Petra; Brand, Willi A.; Kuhlmann, Iris; Horna, Viviana; Schulze, Ernst-Detlef
      Tree Physiology (Victoria, BC, Canada) (2004), 24 (11), 1193-1201CODEN: TRPHEM; ISSN:0829-318X. (Heron Publishing)
      The authors present a new, rapid method for high-resoln. online detn. of δ13C in tree rings, combining laser ablation (LA), combustion (C), gas chromatog. (GC) and isotope ratio mass spectrometry (IRMS) (LA-C-GC-IRMS). Sample material was extd. every 6 min with a UV laser from a tree core, leaving 40-μm-wide holes. Ablated wood dust was combusted to CO2 at 700 °C, sepd. from other gases on a GC column and injected into an isotope ratio mass spectrometer after removal of water vapor. The measurements were calibrated against an internal and an external std. The tree core remained intact and could be used for subsequent dendrochronol. and dendrochem. analyses. Cores from two Scots pine trees (Pinus sylvestris spp. sibirica Lebed.) from central Siberia were sampled. Inter- and intra-annual patterns of δ13C in whole-wood and lignin-extd. cores were indistinguishable apart from a const. offset, suggesting that lignin extn. is unnecessary for this method. Comparison with the conventional method (microtome slicing, elemental anal. and IRMS) indicated high accuracy of the LA-C-GC-IRMS measurements. Patterns of δ13C along three parallel ablation lines on the same core showed high congruence. A conservative est. of the precision was ±0.24‰. Isotopic patterns of the two Scots pine trees were broadly similar, indicating a signal related to the forest stand's climate history. The max. variation in δ13C over 22 years was about 5‰, ranging from -27 to -22.3‰. The most obvious pattern was a sharp decline in δ13C during latewood formation and a rapid increase with spring early growth. The authors conclude that the LA-C-GC-IRMS method will be useful in elucidating short-term climate effects on the δ13C signal in tree rings.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXhtFahtLnE&md5=37346623dc69e3be14af9acc75cf25e6
    25. 25
      Moran, J. J.; Newburn, M. K.; Alexander, M. L.; Sams, R. L.; Kelly, J. F.; Kreuzer, H. W. Laser ablation isotope ratio mass spectrometry for enhanced sensitivity and spatial resolution in stable isotope analysis. Rapid Commun. Mass Spectrom. 2011, 25, 1282– 1290,  DOI: 10.1002/rcm.4985
      Google Scholar
      25
      Laser ablation isotope ratio mass spectrometry for enhanced sensitivity and spatial resolution in stable isotope analysis
      Moran, James J.; Newburn, Matt K.; Alexander, M. Lizabeth; Sams, Robert L.; Kelly, James F.; Kreuzer, Helen W.
      Rapid Communications in Mass Spectrometry (2011), 25 (9), 1282-1290CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)
      Stable isotope anal. permits the tracking of phys., chem., and biol. reactions and source materials at a wide variety of spatial scales. We present a laser ablation isotope ratio mass spectrometry (LA-IRMS) method that enables δ13C measurement of solid samples at 50 μm spatial resoln. The method does not require sample pre-treatment to phys. sep. spatial zones. We use laser ablation of solid samples followed by quant. combustion of the ablated particulates to convert sample carbon into CO2. Cryofocusing of the resulting CO2 coupled with modulation in the carrier flow rate permits coherent peak introduction into an isotope ratio mass spectrometer, with only 65 ng carbon required per measurement. We conclusively demonstrate that the measured CO2 is produced by combustion of laser-ablated aerosols from the sample surface. We measured δ13C for a series of solid compds. using laser ablation and traditional solid sample anal. techniques. Both techniques produced consistent isotopic results but the laser ablation method required over two orders of magnitude less sample. We demonstrated that LA-IRMS sensitivity coupled with its 50 μm spatial resoln. could be used to measure δ13C values along a length of hair, making multiple sample measurements over distances corresponding to a single day's growth. This method will be highly valuable in cases where the δ13C anal. of small samples over prescribed spatial distances is required. Suitable applications include forensic anal. of hair samples, investigations of tightly woven microbial systems, and cases of surface anal. where there is a sharp delineation between different components of a sample. Copyright © 2011 John Wiley & Sons, Ltd.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXks1ajtrc%253D&md5=a4c0a811e92dcf855770cc72a393ca4d
    26. 26
      van Roij, L.; Sluijs, A.; Laks, J. J.; Reichart, G.-J. Stable carbon isotope analyses of nanogram quantities of particulate organic carbon (pollen) with laser ablation nano combustion gas chromatography/isotope ratio mass spectrometry. Rapid Commun. Mass Spectrom. 2017, 31, 47– 58,  DOI: 10.1002/rcm.7769
      Google Scholar
      26
      Stable carbon isotope analyses of nanogram quantities of particulate organic carbon (pollen) with laser ablation nano combustion gas chromatography/isotope ratio mass spectrometry
      van Roij, Linda; Sluijs, Appy; Laks, Jelmer J.; Reichart, Gert-Jan
      Rapid Communications in Mass Spectrometry (2017), 31 (1), 47-58CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)
      Analyses of stable carbon isotope ratios (δ13C values) of org. and inorg. matter remains have been instrumental for much of the understanding of present and past environmental and biol. processes. Until recently, the anal. window of such analyses has been limited to samples contg. at least several μg of carbon. Here the authors present a setup combining laser ablation, nano combustion gas chromatog. and isotope ratio mass spectrometry (LA/nC/GC/IRMS). A deep UV (193 nm) laser was used for optimal fragmentation of org. matter with min. fractionation effects and an exceptionally small ablation chamber and combustion oven were used to reduce the min. sample mass requirement compared with previous studies. Analyses of the international IAEA CH-7 polyethylene std. show optimal accuracy and precision better than 0.5‰, when measuring at least 42 ng C. Application to untreated modern Eucalyptus globulus (C3 plant) and Zea mays (C4 plant) pollen grains shows an ∼16‰ offset between these species. Within each single Z. mays pollen grain, replicate analyses show almost identical δ13C values. Thus, isotopic offsets between individual pollen grains exceed anal. uncertainties, therefore probably reflecting interspecimen variability of ∼0.5-0.9‰. These promising results set the stage for studying both δ13C values and natural carbon isotopic variability between single specimens of a single population of all kinds of org. particles yielding tens of nanograms of carbon.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitVGqtrnP&md5=d9b99042b556ba2fe81a8b08be63f178
    27. 27
      Brand, W. A. PreCon: A Fully Automated Interface for the Pre-Gc Concentration of Trace Gases on Air for Isotopic Analysis. Isot. Environ. Health Stud. 1995, 31, 277– 284,  DOI: 10.1080/10256019508036271
      Google Scholar
      27
      PreCon. A fully automated interface for the pre-GC concentration of trace gases in air for isotopic analysis
      Brand, W. A.
      Isotopes in Environmental and Health Studies (1995), 31 (3-4), 277-84CODEN: IEHSF8 ISSN:. (Gordon & Breach)
      For the high precision isotope anal. of atm. trace gases a computer controlled concn. interface was developed. From small air samples it collects either N2O or CO2 derived from CH4 (at concn. of 0.3 and 1.7 ppm for N2O and CH4, resp.) into a small diam. cold trap (-196°) and interfaces via GC and open split to an isotope ratio mass spectrometer (Finnigan MAT 252) for online isotope evaluation. External preproducibilities for repeated measurements of 100 mL air samples from the same source of <0.2‰ (δ-notation) were achieved for 13C/12C from CH4 and for 15N/14N and 18O/16O from N2O. The precision is adequate to monitor the isotope changes in these gases during a day's course.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XntVegsA%253D%253D&md5=1149bb8292fda8436ffe9cc30eae5748
    28. 28
      Günther, D.; Hattendorf, B. Solid sample analysis using laser ablation inductively coupled plasma mass spectrometry. TrAC, Trends Anal. Chem. 2005, 24, 255– 265,  DOI: 10.1016/j.trac.2004.11.017
      Google Scholar
      28
      Solid sample analysis using laser ablation inductively coupled plasma mass spectrometry
      Guenther, Detlef; Hattendorf, Bodo
      TrAC, Trends in Analytical Chemistry (2005), 24 (3), 255-265CODEN: TTAEDJ; ISSN:0165-9936. (Elsevier B.V.)
      A review. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a highly accepted, widely used method for the detn. of major, minor and trace elements in solids, as well as isotope-ratio measurements. However, it suffers from nonstoichiometric effects occurring during sampling, aerosol transport, vaporization, atomization and ionization within the ICP, described as elemental fractionation. This matrix-dependent phenomenon was the limitation for quant. anal. without matrix-matched calibration stds. Significant insights into the processes responsible for elemental fractionation were obtained and, with improved understanding of LA-ICP-MS, a variety of strategies for more precise, more accurate quant. analyses were developed. This review aims to summarize recent developments in LA-ICP-MS based on the fundamental understanding of the LA process and particle formation but also includes the importance of the ICP and its operating conditions. Figures of merit and new trends in quantification to demonstrate the capabilities of this direct solid-sampling technique are discussed. The authors present a few selected applications to underline why LA is a fast-expanding anal. technique.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhs12kurc%253D&md5=ed53beb61eb6a5f6c14b5115dbb8cc92
    29. 29
      Brand, W. A.; Coplen, T. B.; Vogl, J.; Rosner, M.; Prohaska, T. Assessment of international reference materials for isotope-ratio analysis (IUPAC Technical Report). Pure Appl. Chem. 2014, 86, 425– 467,  DOI: 10.1515/pac-2013-1023
      Google Scholar
      29
      Assessment of international reference materials for isotope-ratio analysis (IUPAC Technical Report)
      Brand, Willi A.; Coplen, Tyler B.; Vogl, Jochen; Rosner, Martin; Prohaska, Thomas
      Pure and Applied Chemistry (2014), 86 (3), 425-467CODEN: PACHAS; ISSN:0033-4545. (Walter de Gruyter, Inc.)
      A review. Since the early 1950s, the no. of international measurement stds. for anchoring stable isotope delta scales has mushroomed from 3 to more than 30, expanding to more than 25 chem. elements. With the development of new instrumentation, along with new and improved measurement procedures for studying naturally occurring isotopic abundance variations in natural and tech. samples, the no. of internationally distributed, secondary isotopic ref. materials with a specified delta value has blossomed in the last six decades to more than 150 materials. More than half of these isotopic ref. materials were produced for isotope-delta measurements of seven elements: H, Li, B, C, N, O, and S. The no. of isotopic ref. materials for other, heavier elements has grown considerably over the last decade. Nevertheless, even primary international measurement stds. for isotope-delta measurements are still needed for some elements, including Mg, Fe, Te, Sb, Mo, and Ge. It is recommended that authors publish the delta values of internationally distributed, secondary isotopic ref. materials that were used for anchoring their measurement results to the resp. primary stable isotope scale.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXmslGlt7k%253D&md5=68bb686894fe9734166102f2e62e6a81
    30. 30
      Krause, L.; Rodionov, A.; Schweizer, S. A.; Siebers, N.; Lehndorff, E.; Klumpp, E.; Amelung, W. Microaggregate stability and storage of organic carbon is affected by clay content in arable Luvisols. Soil Tillage Res. 2018, 182, 123– 129,  DOI: 10.1016/j.still.2018.05.003
      Google Scholar
      There is no corresponding record for this reference.
    31. 31
      Glisczynski, F. v.; Pude, R.; Amelung, W.; Sandhage-Hofmann, A. Biochar-compost substrates in short-rotation coppice: Effects on soil and trees in a three-year field experiment. J. Plant Nutr. Soil Sci. 2016, 179, 574– 583,  DOI: 10.1002/jpln.201500545
      Google Scholar
      There is no corresponding record for this reference.
    32. 32
      Schiedung, H.; Tilly, N.; Hütt, C.; Welp, G.; Brüggemann, N.; Amelung, W. Spatial controls of topsoil and subsoil organic carbon turnover under C3–C4 vegetation change. Geoderma 2017, 303, 44– 51,  DOI: 10.1016/j.geoderma.2017.05.006
      Google Scholar
      32
      Spatial controls of topsoil and subsoil organic carbon turnover under C3-C4 vegetation change
      Schiedung, H.; Tilly, N.; Huett, C.; Welp, G.; Brueggemann, N.; Amelung, W.
      Geoderma (2017), 303 (), 44-51CODEN: GEDMAB; ISSN:0016-7061. (Elsevier B.V.)
      Soil org. carbon (SOC) is often heterogeneously distributed in arable fields and so is probably its turnover. We hypothesized that the spatial patterns of SOC turnover are controlled by basic soil properties like soil texture and the amt. of rock fragments. To test this hypothesis, we cultivated maize as a C4 plant on a heterogeneous arable field (155 × 60 m) that had formerly been solely cultivated with C3 crops, and monitored the incorporation of isotopically heavier maize-derived C into SOC by stable 13C isotope analyses. To obtain a homogeneous input of C4 biomass into the C3 soil across the field, we chopped the aboveground maize biomass after harvest in autumn and re-spread it uniformly over the field. Subsequently, the soil was grubbed and then ploughed in the next spring. In addn., we assessed the spatial patterns of SOC stocks, amt. of rock fragments and texture, as well as potential soil org. matter (SOM) degradability by ex-situ soil respiration measurements. Heterogeneity of maize growth was monitored as a covariate using laser scanning and satellite images. After two years, maize C had substituted 7.4 ± 3.2% of SOC in the topsoil (0-30 cm) and 2.9 ± 1.7% of SOC in the subsoil (30-50 cm). Assuming that monoexponential decay mainly drove this SOC substitution, this resulted in mean residence times (MRT) of SOC in the range of 30 ± 12 years for the topsoil and of 87 ± 45 years for the subsoil, resp. Variation in topsoil MRT was related to potential CO2 release during soil incubation (R2 = 0.51), but not to basic soil properties. In the subsoil, in contrast, the variation of maize C incorporation into the SOC pool was controlled by variations in maize yield (R2 = 0.44), which also exhibited a pronounced spatial variability (0.84 to 1.94 kg dry biomass m-2), and which was neg. correlated with the amt. of rock fragments (R2 = 0.48, p < 0.001). We assume that heterogeneous input of belowground root biomass blurs the causal interactions between the spatial heterogeneity of soil properties and the related patterns of SOC turnover, and conclude that spatial patterns of SOC turnover are not easily predictable by std. soil analyses.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXotlSqu7c%253D&md5=68a8d5072604888a3ac9d0a2193f1222
    33. 33
      Jeong, S. H.; Borisov, O. V.; Yoo, J. H.; Mao, X. L.; Russo, R. E. Effects of Particle Size Distribution on Inductively Coupled Plasma Mass Spectrometry Signal Intensity during Laser Ablation of Glass Samples. Anal. Chem. 1999, 71, 5123– 5130,  DOI: 10.1021/ac990455a
      Google Scholar
      33
      Effects of Particle Size Distribution on Inductively Coupled Plasma Mass Spectrometry Signal Intensity during Laser Ablation of Glass Samples
      Jeong, S. H.; Borisov, O. V.; Yoo, J. H.; Mao, X. L.; Russo, R. E.
      Analytical Chemistry (1999), 71 (22), 5123-5130CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
      The relation between laser-generated particles and ICPMS signal intensity was studied using single-pulse laser ablation sampling of solids. The particle size distribution of glass samples was measured using an optical particle counter for different laser ablation conditions. Ablation of a new surface produced fewer particles and lower ICPMS signal intensity than a preablated surface. Laser power d. of 0.4-0.5 GW/cm2 is a threshold value, across which particle size distribution changed. Laser beam diam. was a more influential parameter than power d. in efficient particle generation. Particle loss during transport from the ablation chamber to the ICPMS was significant for a low carrier gas flow rate of 0.1 L/min, while almost no loss was obsd. for a higher flow rate of 0.26 L/min. The onset of ICPMS intensity time profiles decreased as more large particles were generated. ICPMS intensity data were calibrated with respect to the particle mass entering the ICPMS. Particle entrainment efficiency of the LA-ICPMS system was estd. and is a strong function of laser power d.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXmtlKqsr0%253D&md5=f42c5f2c8a022be14c3c1b4935b4d7d2
    34. 34
      Ohlsson, K. E. A. Uncertainty of blank correction in isotope ratio measurement. Anal. Chem. 2013, 85, 5326– 5329,  DOI: 10.1021/ac4003968
      Google Scholar
      34
      Uncertainty of Blank Correction in Isotope Ratio Measurement
      Ohlsson, K. E. Anders
      Analytical Chemistry (Washington, DC, United States) (2013), 85 (11), 5326-5329CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
      Blank correction for isotope ratio measurement on small amts. of substances is often limited by presence of a blank, with an apparent isotopic compn. different from that of the sample. For isotope ratios, blank correction is commonly performed either by the regression method, which works without the need for estn. of the blank, or by the subtraction method. With the subtraction method, estn. of the amt. and isotope delta of the blank is required, and these ests. could be obtained either by direct, semi-indirect, or indirect measurement. Previously given expressions for the std. uncertainties of indirectly measured blank amts. and blank isotope deltas did not account for covariance between input quantities. A previously published data set was reevaluated, with covariance terms properly included in the calcn. of uncertainties. Covariance effects may yield a significant redn. in uncertainty ests., both for blank quantities and for blank cor. results. For series measurements on a std. material, also the distribution of individual cor. isotope delta values around the av. value was approx. normal, with its std. deviation equal to the estd. std. uncertainty of the cor. values. In most cases, the regression and subtraction methods yield approx. the same blank cor. av. values and uncertainties, regardless of method selected for estn. of blank quantities.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXntFWlt7w%253D&md5=a11f2702f96c7edfe9e85c016bba9a31
    35. 35
      Werner, R. A.; Brand, W. A. Referencing strategies and techniques in stable isotope ratio analysis. Rapid Commun. Mass Spectrom. 2001, 15, 501– 519,  DOI: 10.1002/rcm.258
      Google Scholar
      35
      Referencing strategies and techniques in stable isotope ratio analysis
      Werner, Roland A.; Brand, Willi A.
      Rapid Communications in Mass Spectrometry (2001), 15 (7), 501-519CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)
      A review, with 53 refs., is given on techniques for reliable standardization in carrier gas or online techniques where an accepted protocol for assigning δ-values on an internationally accepted scale was not yet defined. Stable isotope ratios are reported in the literature in terms of a deviation from an international std. (δ-values). The referencing procedures, however, differ from instrument to instrument and are not consistent between measurement facilities. This paper reviews an attempt to unify the strategy for referencing isotopic measurements. In particular, emphasis is given to the importance of identical treatment of sample and ref. material (IT principle), which should guide all isotope ratio detns. and evaluations. The implementation of the principle in the lab., the monitoring of the measurement quality, the status of the international scales and ref. materials and necessary correction procedures are discussed.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXivFOjsb4%253D&md5=957d85e78f0b6184465f04570c673d5d
    36. 36
      Werner, R. A.; Bruch, B. A.; Brand, W. A. ConFlo III - an interface for high precision δ13C and δ15N analysis with an extended dynamic range. Rapid Commun. Mass Spectrom. 1999, 13, 1237– 1241,  DOI: 10.1002/(SICI)1097-0231(19990715)13:13<1237::AID-RCM633>3.0.CO;2-C
      Google Scholar
      36
      ConFlo III - an interface for high precision δ13C and δ15N analysis with an extended dynamic range
      Werner, Roland A.; Bruch, Beate A.; Brand, Willi A.
      Rapid Communications in Mass Spectrometry (1999), 13 (13), 1237-1241CODEN: RCMSEF; ISSN:0951-4198. (John Wiley & Sons Ltd.)
      A newly developed interface coupling a CHN combustion device (elemental analyzer EA) to an isotope ratio mass spectrometer is described and evaluated. The purpose of the device is to extend the dynamic range of δ13C and δ15N anal. from <2 orders of magnitude to >3 orders of magnitude. Carbon isotope ratio measurements of atropine as a model compd. were performed analyzing between 1 μg to 5 mg C with acceptable to excellent precision (0.6 to 0.06 ‰ -notation). The correction due to the blank signal is crit. for sample amts. smaller than 4 μg C. The max. sample wt. is detd. by the combustion capacity of the EA. Larger sample amts. are measured using diln. of a small part of the EA effluent with helium. The diln. mechanism works virtually free of isotope fractionation.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXksVKrt7s%253D&md5=f6d599b78335134daf1a75a379f0296a
    37. 37
      Borisov, O. V.; Mao, X.; Russo, R. E. Effects of crater development on fractionation and signal intensity during laser ablation inductively coupled plasma mass spectrometry. Spectrochim. Acta, Part B 2000, 55, 1693– 1704,  DOI: 10.1016/S0584-8547(00)00272-X
      Google Scholar
      37
      Effects of crater development on fractionation and signal intensity during laser ablation inductively coupled plasma mass spectrometry
      Borisov, Oleg V.; Mao, Xianglei; Russo, Richard E.
      Spectrochimica Acta, Part B: Atomic Spectroscopy (2000), 55B (11), 1693-1704CODEN: SAASBH; ISSN:0584-8547. (Elsevier Science B.V.)
      The effects of crater development on ICP-MS signal intensities and elemental fractionation were presented. Craters formed after repetitive 266-nm Nd/YAG laser ablation with 1.0-mJ pulses had a cone-like shape. The laser ablation rate (ng/s) depended on the laser irradiance (laser pulse energy per unit time and unit area), decreasing as irradiance increased. In contrast, the particle entrainment/transport efficiency did not significantly change with irradiance. As the crater-aspect ratio (depth/diam.) increased above some threshold value of six, the Pb/U elemental ratio departed from the stoichiometric value. However, good stoichiometry of ablated mass could be achieved when exptl. conditions were carefully selected. The exact mechanism of how crater development affects fractionation is not well understood. Actual irradiance was introduced instead of a nominal value. Actual irradiance decreased as the crater deepened due to changes of the effective area, sampled by the laser beam.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXosV2ntr0%253D&md5=5ca41b722adbdb23f3155a7c3ffbcd7e
    38. 38
      Bleiner, D.; Plotnikov, A.; Vogt, C.; Wetzig, K.; Günther, D. Depth profile analysis of various titanium based coatings on steel and tungsten carbide using laser ablation inductively coupled plasma--″time of flight″ mass spectrometry. Fresenius' J. Anal. Chem. 2000, 368, 221– 226,  DOI: 10.1007/s002160000417
      Google Scholar
      38
      Depth profile analysis of various titanium based coatings on steel and tungsten carbide using laser ablation inductively coupled plasma - "time of flight" mass spectrometry
      Bleiner, Davide; Plotnikov, Alexei; Vogt, Carla; Wetzig, Klaus; Gunther, D.
      Fresenius' Journal of Analytical Chemistry (2000), 368 (2-3), 221-226CODEN: FJACES; ISSN:0937-0633. (Springer-Verlag)
      A homogenized 193 nm ArF* laser ablation system coupled to an inductively coupled plasma-Time of Flight-mass spectrometer (LA-ICP-TOFMS) was tested for depth profiling anal. on different single-layer Ti based coatings on steel and W carbides. Laser parameters, such as repetition rate, pulse energy and spatial resoln. were tested to allow optimum depth related calibration curves. The ablation process using a laser repetition rate of 3 Hz, 120 μm crater diam., and 100 mJ output energy, leads to linear calibration curves independent of the drill time or peak area used for calibrating the thickness of the layer. The best depth resoln. obtained (without beam splitter) was 0.20 μm per laser shot. The time resoln. of the ICP-TOFMS of 102 ms integration time per isotope was sufficient for the detn. of the drill time of the laser through the coatings into the matrix with better than 2.6% relative std. deviation (∼7 μm coating thickness, n = 7). Variation of the vol. of the ablation cell was not influencing the depth resoln., which suggests that the depth resoln. is governed by the ablation process. However, the application on the Ti(N,C) based single layer shows the potential of LA-ICP-TOFMS as a complementary technique for fast depth detns. on various coatings in the low to medium μm region.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXmtFGmtbw%253D&md5=c453500ab5eaf8fcd7a65a7032e6a840
    39. 39
      Paul, E. A.; Follett, R. F.; Leavitt, S. W.; Halvorson, A.; Peterson, G. A.; Lyon, D. J. Radiocarbon dating for determination of soil organic matter pool sizes and dynamics. Soil Sci. Soc. Am. J. 1997, 61, 1058– 1067,  DOI: 10.2136/sssaj1997.03615995006100040011x
      Google Scholar
      39
      Radiocarbon dating for determination of soil organic matter pool sizes and dynamics
      Paul, E. A.; Follett, R. F.; Leavitt, S. W.; Halvorson, A.; Peterson, G. A.; Lyon, D. J.
      Soil Science Society of America Journal (1997), 61 (4), 1058-1067CODEN: SSSJD4; ISSN:0361-5995. (Soil Science Society of America)
      The size and turnover rate of the resistant soil org. matter (SOM) fractions were measured by 14C dating and 13C/12C measurements. This involved soils archived in 1948, and recent samples, from a series of long-term sites in the North American Great Plains. A reevaluation of C dates obtained in the 1960s expanded the study scope. The 14C ages of surface soils were modern in some native sites and near modern in the low, moist areas of the landscape. They were much older at the catena summits. The 14C ages were not related to latitude, although this strongly influenced the total SOM content. Cultivation resulted in lower C contents and increased the 14C age by an av. of 900 yr. The 10- to 20-cm depths from both cultivated and native sites were 1200 yr older than the 0- to 10-cm depth. The 90- to 120-cm depth of a cultivated site at 7015 yr before present (BP) was 6000 yr older than the surface. The nonhydrolyzable C of this depth dated 9035 yr BP. The residue of 6 M HCl hydrolysis comprised 23 to 70% of the total soil C and was, on the av., 1500 yr older. The percentage of nonhydrolyzable C and its 14C age anal. identify the amt. and turnover rate of the old resistant soil C.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXlt1Shsb8%253D&md5=519bab0af6bdb74364f107a154360095
    40. 40
      Holz, M.; Zarebanadkouki, M.; Kuzyakov, Y.; Pausch, J.; Carminati, A. Root hairs increase rhizosphere extension and carbon input to soil. Ann. Bot. 2018, 121, 61– 69,  DOI: 10.1093/aob/mcx127
      Google Scholar
      40
      Root hairs increase rhizosphere extension and carbon input to soil
      Holz, Maire; Zarebanadkouki, Mohsen; Kuzyakov, Yakov; Pausch, Johanna; Carminati, Andrea
      Annals of Botany (Oxford, United Kingdom) (2018), 121 (1), 61-69CODEN: ANBOA4; ISSN:1095-8290. (Oxford University Press)
      • Background and Aims Although it is commonly accepted that root exudation enhances plant-microbial interactions in the rhizosphere, exptl. data on the spatial distribution of exudates are scarce. Our hypothesis was that root hairs exude org. substances to enlarge the rhizosphere farther from the root surface. • Methods Barley (Hordeum vulgare 'Pallas' - wild type) and its root-hairless mutant (brb) were grown in rhizoboxes and labeled with 14CO2. A filter paper was placed on the soil surface to capture, image and quantify root exudates. • Key Results Plants with root hairs allocated more carbon (C) to roots (wild type: 13 %; brb: 8 % of assimilated 14C) and to rhizosheaths (wild type: 1.2 %; brb: 0.2 %), while hairless plants allocated more C to shoots (wild type: 65 %; brb: 75 %). Root hairs increased the radial rhizosphere extension three-fold, from 0.5 to 1.5 mm. Total exudation on filter paper was three times greater for wild type plants compared to the hairless mutant. • Conclusion Root hairs increase exudation and spatial rhizosphere extension, which probably enhance rhizosphere interactions and nutrient cycling in larger soil vols. Root hairs may therefore be beneficial to plants under nutrient-limiting conditions. The greater C allocation below ground in the presence of root hairs may addnl. foster C sequestration.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXmt1SrtrY%253D&md5=5f69bc3006385034bcf6a360b8108846

  • Supporting Information

    Supporting Information

    ARTICLE SECTIONS
    Jump To

    The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.analchem.9b00892.

    • One table and six figures showing the determination of carbon amount by measurements of crater depth on an acryl plate (Table S-1), configuration of the newly developed laser cells (Figure S-1), images of press-pellets from the ground and mixed standard substances (Figure S-2), images of spot depth and surface mapping of ablated spots (Figure S-3), deviation of the δ13C signal from referenced values due to the contribution of the blank signal (Figure S-4), adjustment of loading times in the cryo-trap (Figure S-5), and stable C isotope signatures of a Miscanthus rhizome and the surrounding soil (Figure S-6) (PDF)


    Terms & Conditions

    Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

PDF [ 5MB]

Pair your accounts.

Export articles to Mendeley

Get article recommendations from ACS based on references in your Mendeley library.

Pair your accounts.

Export articles to Mendeley

Get article recommendations from ACS based on references in your Mendeley library.

You’ve supercharged your research process with ACS and Mendeley!

STEP 1:
Click to create an ACS ID

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

MENDELEY PAIRING EXPIRED
Your Mendeley pairing has expired. Please reconnect