Iso Christl


Last Name

Christl

First Name

Iso

ORCID

0000-0003-0566-8635

Organisational unit

03541 - Kretzschmar, Ruben / Kretzschmar, Ruben

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Publications1 - 10 of 77
  • Chemical composition of aquatic dissolved organic matter in five boreal forest catchments sampled in spring and fall seasons
    Item type: Journal Article
    Schumacher, Marc; Christl, Iso; Vogt, Rolf D.; et al. (2006)
    Biogeochemistry
  • Suitability of biochars produced from rice and oil palm residues as amendments for trace element-affected acidic tropical soils
    Item type: Other Conference Item
    Christl, Iso; Wisawapipat, Worachart (2019)
    Online Abstracts: ICOBTE 2019
  • Isolation and purification of Cu-free methanobactin from Methylosinus trichosporium OB3b
    Item type: Journal Article
    Pesch, Marie-Laure; Christl, Iso; Barmettler, Kurt; et al. (2011)
    Geochemical transactions
    Background The isolation of highly pure copper-free methanobactin is a prerequisite for the investigation of the biogeochemical functions of this chalkophore molecule produced by methane oxidizing bacteria. Here, we report a purification method for methanobactin from Methylosinus trichosporium OB3b cultures based on reversed-phase HPLC fractionation used in combination with a previously reported resin extraction. HPLC eluent fractions of the resin extracted product were collected and characterized with UV-vis, FT-IR, and C-1s NEXAFS spectroscopy, as well as with elemental analysis and ESI-MS. Results The results showed that numerous compounds other than methanobactin were present in the isolate obtained with resin extraction. Molar C/N ratios, mass spectrometry measurements, and UV-vis spectra indicated that methanobactin was only present in one of the HPLC fractions. On a mass basis, methanobactin carbon contributed only 32% to the total organic carbon isolated with resin extraction. Our spectroscopic results implied that besides methanobactin, the organic compounds in the resin extract comprised breakdown products of methanobactin as well as polysaccharide-like substances. Conclusion Our results demonstrate that a purification step is indispensable in addition to resin extraction in order to obtain pure methanobactin. The proposed HPLC purification procedure is suitable for semi-preparative work and provides copper-free methanobactin.
  • Copper and lead binding to minerals coated with fulvic acid
    Item type: Conference Paper
    Christl, Iso; Heidmann, Ilona; Kretzschmar, Ruben (2004)
    Geochimica et Cosmochimica Acta
  • Two-year and multi-site field trials to evaluate soil amendments for controlling cadmium accumulation in rice grain
    Item type: Journal Article
    Fang, Xu; Wang, Jing; Chen, Hongping; et al. (2021)
    Environmental Pollution
    Representing the staple crop for half of the world population, rice can accumulate high levels of cadmium (Cd) in its grain, posing concerns on food safety. Different soil amendments have been proposed to decrease Cd accumulation in rice grain by either decreasing soil Cd availability, introducing competitive ions on Cd uptake, or down-regulating the expression of transporters for Cd uptake. However, the effectiveness of soil amendments applied alone or in combinations needs to be tested under field conditions. Here, we present results of field trials with two rice cultivars differing in Cd accumulation grown at three field sites in southern China in two years, to investigate the effects of two Mn-containing soil amendments (MnO2, Mn-loaded biochar (MB)), Si fertilizer (Si), limestone, and K2SO4, as well as interactions among MnO2, Si, and limestone on decreasing Cd accumulation in rice grain. We found that single applications of MnO2 or MB to acidic soils low in Mn decreased grain Cd concentrations by 44–53 % or 78–82 %, respectively, over two years without decrease in performance. These effects were comparable to or greater than those induced by limestone liming alone (45–62 %). Strong interactions between MnO2 and limestone resulting from their influence on soil extractable Cd and Mn led to non-additive effects on lowering grain Cd. MB addition minimized grain Cd concentrations, primarily by increasing extractable and dissolved Mn concentrations, but also by decreasing Cd extractability in soil. In comparison, Si and K2SO4 amendments affected grain Cd levels only weakly. We conclude that the amendments that decrease labile Cd and increase labile Mn in soils are most effective at reducing Cd accumulation in rice grain, thus contributing to food safety.
  • Copper Redox Transformation and Complexation by Reduced and Oxidized Soil Humic Acid
    Item type: Journal Article
    Fulda, Beate; Voegelin, Andreas; Maurer, Felix; et al. (2013)
    Environmental Science & Technology
  • Sulfur amendments to soil decrease inorganic arsenic accumulation in rice grain under flooded and nonflooded conditions: Insights from temporal dynamics of porewater chemistry and solid-phase arsenic solubility
    Item type: Journal Article
    Wisawapipat, Worachart; Chooaiem, Netisuk; Aramrak, Surachet; et al. (2021)
    Science of The Total Environment
    Rice cultivation under flooded conditions enhances arsenic (As) solubility and favors As accumulation in rice grain that poses an indisputable threat to human health worldwide. The reduction of sulfur may induce processes that decrease As solubility, but its impact on rice grain As species remains unresolved. Herein, we investigated the influence of sulfur (S)-containing materials, including chicken manure and elemental sulfur powder on As accumulation and speciation in rice grain as well as the dynamics of the porewater chemistry and solid-phase As solubility throughout the entire growth stage under continuous flooding and intermittent flooding conditions in pot experiments. The S amendments (200 mg S kg−1) to the soil significantly decreased inorganic As in rice grain under continuous flooding (~65% decrease) as well as under intermittent flooding (~70% decrease). The chicken manure amendment promoted sulfur reduction and enhanced dissolvable Mn, Fe, and As at an earlier growth stage. The sequential extraction results corroborated a decrease in the soluble and exchangeable As (F1) and an increase in residual As (F5) fractions in the S-amended treatments. Solubility data suggested that As adsorption onto Fe oxides was the primary mechanism controlling As solubility rather than the formation of Assingle bondFe sulfides. Porewater As, considered to represent the most bioavailable As fraction, failed to explain the grain As accumulation. The time-averaged concentration of oxalate-extractable As explained grain arsenite best, suggesting that poorly crystalline Fe oxides may be the primary dissolvable reactive phases that control As bioavailability in the soil-rice system. Our results suggest that the application of S-containing soil amendments can effectively decrease inorganic As accumulation in rice grains grown under the flooded conditions, which are most widely applied in paddy rice production.
  • Copper complexation of methanobactin isolated from Methylosinus trichosporium OB3b: pH-dependent speciation and modeling
    Item type: Journal Article
    Pesch, Marie-Laure; Christl, Iso; Hoffmann, Martin; et al. (2012)
    Journal of Inorganic Biochemistry
  • Soil-to-plant transfer of arsenic and phosphorus along a contamination gradient in the mining-impacted Ogosta River floodplain
    Item type: Journal Article
    Simmler, Michael; Suess, Elke; Christl, Iso; et al. (2016)
    Science of The Total Environment
  • Competitive ligand exchange between Cu-humic acid complexes and methanobactin
    Item type: Journal Article
    Pesch, Marie-Laure; Hoffmann, Martin; Christl, Iso; et al. (2013)
    Geobiology
Publications1 - 10 of 77