78 results on '"Schaumann, Gabriele Ellen"'
Search Results
2. Multiannual soil mulching in agriculture: analysis of biogeochemical soil processes under plastic and straw mulches in a 3-year field study in strawberry cultivation
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Meyer, Maximilian, Diehl, Dörte, Schaumann, Gabriele Ellen, and Muñoz, Katherine
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- 2021
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3. Influence of the physico-chemical properties of root mucilage and model substances on the microstructural stability of sand
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Brax, Mathilde, Buchmann, Christian, Kenngott, Kilian, Schaumann, Gabriele Ellen, and Diehl, Dörte
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- 2020
4. Agricultural mulching and fungicides—impacts on fungal biomass, mycotoxin occurrence, and soil organic matter decomposition
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Meyer, Maximilian, Diehl, Dörte, Schaumann, Gabriele Ellen, and Muñoz, Katherine
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- 2021
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5. Effect of matric potential and soil-water-hydrogel interactions on biohydrogel-induced soil microstructural stability
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Buchmann, Christian, Steinmetz, Zacharias, Brax, Mathilde, Peth, Stephan, and Schaumann, Gabriele Ellen
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- 2020
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6. Potential of NMR relaxometry to unravel the properties of mucilage in several pore sizes
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Brax, Mathilde, Köhne, Maximilian, Kroener, Eva, and Schaumann, Gabriele Ellen
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- 2019
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7. Effect of mucilage on water properties in the rhizosphere monitored by 1H-NMR relaxometry
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Brax, Mathilde, Buchmann, Christian, and Schaumann, Gabriele Ellen
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- 2018
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8. Physico-Chemical Soil Properties Affected by Invasive Plants in Southwest Germany (Rhineland-Palatinate)—A Case Study.
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Jamin, Jellian, Diehl, Dörte, Meyer, Michele, David, Jan, Schaumann, Gabriele Ellen, and Buchmann, Christian
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INVASIVE plants ,PORE size distribution ,PLANT biomass ,STINGING nettle ,SOIL depth ,RIPARIAN areas - Abstract
The invasive plant species Impatiens glandulifera native to Asia mainly occupies European riparian ecosystems. It is still unclear to which extent this invasive plant can alter physico-chemical soil properties in terms of carbon turnover, microstructural stability and soil hydraulic properties threatening native plant species, here represented by Urtica dioica. Soil samples were collected from three sites in the Palatine forest near the river Queich, including bare soil (Control), or soil within dense stands of either I. glandulifera or U. dioica with similar texture. Basic soil parameters including SOM content and quality were analyzed. SOM is known to impact soil microstructural stability and soil hydraulic properties. We therefore assessed microstructural stability, the pore size distribution and the wettability. Our results implied more recalcitrant SOM for soil colonized by U. dioca including a lower pH. For soil colonized by I. glandulifera less recalcitrant SOM was detected indicating a reduced degradation which is likely given due to lignin as a predominant component in the plant biomass of I. glandulifera Soil microstructural stability was higher for soil colonized by the invader showing a slight increase with soil depth, due to higher SOM content. All in all, this case study indicates that I. glandulifera most likely affects the soil microbiome while basic soil parameters, soil hydraulic properties, wettability and soil microstructural stability showed no significant effect. [ABSTRACT FROM AUTHOR]
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- 2022
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9. Hydration of humic and fulvic acids studied by DSC
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Kučerík, Jiří, Bursáková, Petra, Průšová, Alena, Grebíková, Lucie, and Schaumann, Gabriele Ellen
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- 2012
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10. Potential of AFM–nanothermal analysis to study the microscale thermal characteristics in soils and natural organic matter (NOM)
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Schaumann, Gabriele Ellen and Kunhi Mouvenchery, Yamuna
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- 2012
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11. Natural TiO2-Nanoparticles in Soils: A Review on Current and Potential Extraction Methods.
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Campos, Daniel Armando, Schaumann, Gabriele Ellen, and Philippe, Allan
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ANTHROPOGENIC soils , *SOILS , *KAOLIN , *ELECTROPHORETIC deposition , *GEL electrophoresis , *SOIL sampling , *FLOCCULATION - Abstract
The monitoring of anthropogenic TiO2-nanoparticles in soils is challenged by the knowledge gap on their characteristics of the large natural TiO2-nanoparticle pool. Currently, no efficient method is available for characterizing natural TiO2-nanoparticles in soils without an extraction procedure. Considering the reported diversity of extraction methods, the following article reviews and discusses their potential for TiO2 from soils, focusing on the selectivity and the applicability to complex samples. It is imperative to develop a preparative step reducing analytical interferences and producing a stable colloidal dispersion. It is suggested that an oxidative treatment, followed by alkaline conditioning and the application of dispersive agents, achieve such task. This enables the further separation and characterization through size or surface-based separation (i.e., hydrodynamic fractionation methods, filtration or sequential centrifugation). Meanwhile, cloud point extraction, gel electrophoresis, and electrophoretic deposition have been studied on various nanoparticles but not on TiO2-nanoparticles. Furthermore, industrially applied methods in, for example, kaolin processing (flotation and flocculation) are interesting but require further improvements on terms of selectivity and applicability to soil samples. Overall, none of the current extraction methods is sufficient toward TiO2; however, further optimization or combination of orthogonal techniques could help reaching a fair selectivity toward TiO2. [ABSTRACT FROM AUTHOR]
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- 2022
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12. Coevolution of organic substances and soils: links between soil forming processes and the stabilisation of organic substances
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Lang, Friederike, Schaumann, Gabriele Ellen, Thiele-Bruhn, Sören, Schaeffer, Andreas, Fründ, Heinz-Christian, and Schwarzbauer, Jan
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- 2012
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13. Erratum to: Potential of AFM–nanothermal analysis to study the microscale thermal characteristics in soils and natural organic matter (NOM)
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Schaumann, Gabriele Ellen and Kunhi Mouvenchery, Yamuna
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- 2012
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14. Gel formation mechanism and gel properties controlled by Ca2+ in chia seed mucilage and model substances.
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Brax, Mathilde, Schaumann, Gabriele Ellen, and Diehl, Dörte
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CHIA , *MUCILAGE , *URONIC acids , *CALCIUM , *ESTERIFICATION - Abstract
Polygalacturonic acid (PGA) is considered as a model substance for mucilage to study mucilage–soil interactions, assuming that the gel formation mechanism of mucilage is comparable to the one of PGA. However, some studies question the accepted hypothesis, which states that, like for PGA, this mechanism relies on cross‐links between uronic acid and calcium for mucilage. The aim of this study was therefore to understand the influence of the abundance and degree of esterification of uronic acids and the influence of calcium on the gel formation mechanism in mucilage as compared to model substances. The mucilage used was from chia seeds, as it is easily available in great quantity and has gel properties shared by root mucilage. Results reported here demonstrate that, while the gel formation mechanism of PGA relied on specific cross‐links with calcium and led to heterogeneous gels, low‐methoxy pectin (LMP) formed homogeneous calcium gels also characterized by nonspecific ionic interactions with calcium. On the contrary, despite similar uronic acid content to LMP, chia seed mucilage was mostly governed by weak electrostatic interactions between entangled polymer chains, which conferred the gel poor water retention. Addition of calcium reduced repulsion and molecular expansion, resulting in a reduction of the water content in chia seed mucilage. Finally, the discrepancies between PGA, LMP and chia seed mucilage discredit the use of PGA as model for chia seed mucilage. Comparison with root mucilage is still needed. This study offers the keys for further mechanistic understanding on the influence of mucilage on soil properties. [ABSTRACT FROM AUTHOR]
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- 2019
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15. Characterization of Wet Aggregate Stability of Soils by 1H‐NMR Relaxometry
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Buchmann, Christian, Meyer, Maximilian, and Schaumann, Gabriele Ellen
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- 2014
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16. Cation binding in a soil with low exchange capacity: Implication for the structural rigidity of soil organic matter.
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Mouvenchery, Yamuna Kunhi and Schaumann, Gabriele Ellen
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HUMUS , *ION exchange (Chemistry) , *STRUCTURAL rigidity , *TRANSITION temperature , *BINDING sites - Abstract
Abstract: Two previous studies suggested that part of the cation sorption sites in soil organic matter with low exchange capacity have to be considered as “lonely”, i.e., too far from each other to allow direct cross‐linking by bivalent cations. The objective of this contribution was to understand the mechanisms controlling structural rigidity and physicochemical aging of the SOM (soil organic matter) and the role of water molecule bridges (WaMB) therein. For this, we evaluated the matrix rigidity of an organic surface layer of a Haplic Podzol on a quantitative basis, by assessing WaMB transition temperature (T*) directly after treatment with bivalent cations (Mg2+, Ca2+, or Ba2+) and after eight weeks of aging. Cation loading as well as cation type influenced matrix rigidity. Ba2+ induced the most rigid matrix and Mg2+ the weakest, which is in line with their binding strength in terms of Langmuir coefficient. The matrix rigidity increased with the cross‐linking activity, which is the product of loading and Langmuir constant of the respective cation. The aging process, however, was slowed down by the initial matrix rigidity, and the rigidity of the aged matrix decreased with increasing Langmuir constant. The degree of aging increased with increasing hydration enthalpy of the cation and decreased with increasing cation loading. Thus, directly after cation treatment, direct cross‐links by multivalent cations were most relevant, but WaMB increasingly gained influence on the matrix rigidity during aging. The untreated sample revealed a considerable number of WaMB, resulting in a fairly rigid and strongly cross‐linked matrix which, however, flexibly reacts on external influences like change in cation concentration or relative humidity. With these findings, the ideas on the relevance of indirect CaB‐WaMB associations between distant sorption sites for the rigidity and flexibility of the OM matrix as proposed in previous studies were confirmed on a mechanistic basis in this study. [ABSTRACT FROM AUTHOR]
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- 2018
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17. Considerations on cross‐linking by bivalent cations in soil organic matter with low exchange capacity.
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Schaumann, Gabriele Ellen and Kunhi Mouvenchery, Yamuna
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HUMUS , *ION exchange (Chemistry) , *SOIL sampling , *FOREST soils , *CROSSLINKING (Polymerization) - Abstract
Abstract: A soil's cation exchange capacity (CEC) is expected to be relatively inert against changes in cation loading. In this study, we treated a soil sample originating from the organic layer of a forest soil with various bivalent cations after removing the native cations. Sorption isotherms and cation exchange capacity were determined, the latter using the BaCl2 method. Sorption showed Langmuir characteristics, with the maximum coverage (Qmax) increasing in the order Ba2+ < Ca2+ < Mg2+, but being clearly smaller than the initial load of native exchangeable cations. The Langmuir coefficient, kMe, depended oppositely to the order obtained for Qmax. CEC increased upon cation treatment and it varied by a factor of almost two. The unexpected variation of CEC was explained by the low cation exchange capacity of the organic matter such that not all functional groups are close enough to be bridged and the second charge of a bivalent cation is not neutralized by the organic functional group. The Langmuir sorption type, and Qmax being smaller than the content of sorption sites and being largest for Mg, suggested that only a part of the sites can be cross‐linked and at least part of the cross‐links are formed by hydrated cations. Thermodynamic considerations allowed reconstruction of two contrasting processes during CEC determination by Ba2+: Case A: the disruption of cross‐links, which increases with the cationic strength and the cation load before CEC determination, but does not require structural re‐orientation in the SOM matrix, and Case B: the formation of new cross‐links during CEC determination, depending only on the content of unoccupied sites before CEC determination and requiring structural re‐organization of the matrix and thus a minimum matrix flexibility. The use of bivalent cations for CEC determination may thus result in an overestimation of CEC for organic matter with low CEC. This has, however, promising potential when comparing CEC determined with monovalent cations and bivalent cations. Using a set of bivalent cations, may allow probing distribution of distances between functional groups in the organic matter and even characterize the matrix rigidity of the cation‐cross‐linked network. [ABSTRACT FROM AUTHOR]
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- 2018
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18. The Amorphous Nature of Soil Organic Matter - Aging, Swelling and Wetting and their interplay with water
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Schaumann, Gabriele Ellen, Rotard, Wolfgang, and Technische Universität Berlin, Fakultät III - Prozesswissenschaften
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ddc:500 - Abstract
Boden ist unter Feldbedingungen einer Dynamik von Temperatur und Feuchte ausgesetzt. Dadurch werden Quellungs- und Schrumpfungsprozesse sowie Veränderungen in den Oberflächeneigenschaften der organischen Bodensubstanz induziert, die nur in den seltensten Fällen vollständig reversibel sind. Von diesen Veränderun-gen werden direkte Auswirkungen auf das Sorptions- und Transportverhalten organischer Schadstoffe erwartet. Trotz dieser Bedeutung sind die zugrunde liegenden Prozesse bis heute noch weitgehend unverstanden. Ziel dieser Arbeit war es, die organische Bodensubstanz, basierend auf der Modell-vorstellung als amorphe Matrix, von einem neuen Blickwinkel zu beschreiben. Mit Hilfe der in der Bodenchemie noch wenig bekannten Methoden der 1H-NMR-Relaxometrie und Differential Scanning Kalorimetrie wurden ihre Wasserbindung und Matrixeigenschaften charakterisiert. Im Zentrum stand die Charakterisierung des Glasübergangsverhaltens und der physikalischen Alterung sowie deren Beeinflus-sung durch Wasser, Feuchtebedingungen und Temperatur. Die organische Bodensubstanz zeigt sowohl typisches als auch irreversibles Glas-übergangsverhalten, wobei Wasser in antagonistischer Weise als kurzfristig wirken-der Weichmacher und langfristig wirkender Hartmacher fungiert. Die zugrunde liegenden Strukturrelaxationsprozesse äußern sich in einer langsamen physikochemi-schen Alterung der organischen Matrix über einen Zeitraum von mindestens sechs Monaten. Änderungen in den Feuchtebedingungen führen zu einer Beschleunigung und teilweisen Umkehrung der Alterung. Hystereseeffekte als typisches Merkmal amorpher Stoffe wurden bei Matrixeigenschaften und bei Wasseraufnahme und -abgabe beobachtet. Quellungsprozesse führen zu einer Veränderung der Poreneigenschaften, Porengrößen und Wasserbindung. Die Matrixalterung könnte auch für die zeitliche Variabilität der Benetzungseigenschaften von Bodenproben verantwortlich sein, und mikrobiell gebildete extrazelluläre Substanzen stellen einen weiteren wichtigen Einflussfaktor dar. Die Ergebnisse zeigen die Bedeutung der Matrixalterung für Sorption und Stofftrans-port in bodenkundlich relevanten Zeiträumen. Das Verständnis der Matrixalterung kann zu einem tieferen Verständnis der Alterung sorbierter Schadstoffe führen. In der weiteren Forschung sollen deshalb Zusammenhänge zwischen Struktur, Mikrobiologie, Alterung und Schadstoffbindung untersucht werden. Under field conditions, soil is subjected to temperature and moisture dynamics. These induce swelling and shrinking as well as changes in the surface characteristics of soil organic matter, which are not fully reversible. These changes are expected to affect sorption and transport of organic contaminants. Despite this relevance, the underlying processes are still only scarcely understood. The objective of this research were to describe soil organic matter from a new viewpoint considering it as amorphous matrix. Water binding and matrix properties were characterized with 1H-NMR-Relaxometry and Differential Scanning Calorimetry, both of which represent young methods in the field of soil chemistry. We characterized the glass transition behavior and physical and physicochemical aging of soil organic matter and their interplay with water, moisture conditions and temperature. Soil organic matter reveals typical as well as atypical glass transition behavior, where water acts in antagonistic way as short-term plasticizer and long-term antiplasticizer. The processes of structural relaxation express in physicochemical aging of the organic matrix, and lasts for at least six months. Fluctuations and changes of moisture conditions accelerated or reversed the aging process. We observed hysteresis for water absorption as well as matrix properties, and swelling most probably results in a change of pore size, pore characteristics and water binding. Matrix aging may also be responsible for the changes in soil wettability in the course of time, and extracellular polymeric substances (EPS) most probably are additionally involved in the aging process. The results show the relevance of matrix aging for sorption and transport. Understanding of the processes underlying and affecting aging of soil organic matter, will lead to a better understanding of contaminant aging. Future research therefore should concentrate on the interrelations between structure, microbiology and aging of contaminants and soil organic matter.
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- 2006
19. Biohydrogel induced soil-water interactions: how to untangle the gel effect? A review.
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Brax, Mathilde, Buchmann, Christian, and Schaumann, Gabriele Ellen
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SOIL moisture ,HYDROGELS ,POROSITY ,MAGNETIC resonance ,RHEOLOGY - Abstract
Biohydrogels such as microbial exudates and root-derived mucilage are soil-born cross-linked polymers, able to form porous three-dimensional networks during water uptake. The gel effect is the variation of soil properties, such as soil hydrology and soil structural stability, resulting from biohydrogel swelling in soil. Conventionally, soil-water-hydrogel interactions are investigated by measuring soil bulk properties such as water retention curves and porosity, without further analyzing the effect of biohydrogel phases in soil on a quantitative basis. Therefore, the evaluation of advanced and novel methods for the characterization of biohydrogel phases in soil and soil-water-hydrogel interactions is necessary. This review evaluates currently available methods for their potential to analyze processes associated to the gel effect. A promising approach to investigate the spatio-temporal distribution of biohydrogel phases in porous media is based on Nuclear Magnetic Resonance (NMR) such as
1 H-NMR relaxometry, as well as on imaging techniques such as Environmental Scanning Electron Microscopy (ESEM). Especially NMR techniques enable the identification of different water populations based on their differences in the relaxation, and thus the mobility of water molecules in biohydrogels and non-gel water in soil pores. Rheology measures the flow behavior of biohydrogels, providing information on the structural behavior of the hydrogel network and its gelling mechanism. Soil rheology further quantifies the effect of the biohydrogel phases on the interactions between soil particles, and thus the impact on soil microstructural stability. However, rheology does not elucidate the spatio-temporal distribution and structural state of biohydrogel phases in soil. All in all, a systematic combination of rheology, NMR and suitable imaging methods seems promising and necessary in order to elucidate the still widely unknown gel effect in soil. [ABSTRACT FROM AUTHOR]- Published
- 2017
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20. Linking atomic force microscopy with nanothermal analysis to assess microspatial distribution of material characteristics in young soils.
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Mouvenchery, Yamuna Kunhi, Miltner, Anja, Schurig, Christian, Kästner, Matthias, and Schaumann, Gabriele Ellen
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ATOMIC force microscopy ,THERMAL expansion ,SOIL formation ,THERMODYNAMICS ,ISOTHERMAL expansion ,THERMAL stresses ,SOIL composition - Abstract
Coupling of atomic force microscopy (AFM) with nanothermal analysis (nTA) has the potential to assess material characteristics in soils on the lower µm-scale, but has been shown to require additional characteristics for clear distinction of materials. The objective of this study was to evaluate to which extent the combination of AFM-nTA with AFM adhesion force analysis and structural features allows distinction of organic materials in soils. Using soil samples from a chronosequence from the Damma Glacier forefield, Switzerland, as example, we tested a grid analysis approach for assessing distribution of adhesion forces and nanothermal characteristics. This approach was compared with an approach involving pre-selection of structural features of interest via morphological criteria. Only three types of nanothermograms were distinguished in the soil samples based on different thermal expansion-compression characteristics and phase transition temperatures. Combined evaluation of nanothermal characteristics, adhesion forces and morphological characteristics allowed distinction of a larger set of materials than using nanothermal analysis, adhesion force distribution or morphological characteristics separately. Part of the analyzed features showed a combination of characteristics similar to that of fresh bacterial cells which we analyzed as a potential reference material. Their stronger occurrence in the regions of interest of older samples than in those of younger samples may underline their relevance in soil development. Achieving the long-term objective of identification of materials still requires more information on reference materials, understanding the impact of mixed layering of materials on thermal profiles and the assessment of variability of the characteristics within and between different material groups. [ABSTRACT FROM AUTHOR]
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- 2016
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21. The seasonal influence of olive mill wastewater applications on an orchard soil under semi-arid conditions.
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Steinmetz, Zacharias, Kurtz, Markus Peter, Dag, Arnon, Zipori, Isaac, and Schaumann, Gabriele Ellen
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OLIVE oil mills ,WASTEWATER treatment ,ORCHARDS ,SOIL testing ,OLIVE oil industry ,ARID regions - Abstract
Olive oil production generates large amounts of olive mill wastewater (OMW). OMW has a high nutrient content and could serve as fertilizer, but its fatty and phenolic constituents induce soil water repellency, phytotoxicity, and acidification. An appropriate season of OMW application may mitigate negative consequences while preserving beneficial effects. In order to investigate this, a field study was conducted, in which OMW was applied to an olive orchard in Israel either in winter or summer. Soil-water interactions (water drop penetration time, hydraulic conductivity), soil physicochemical parameters, phenolic compounds, and soil biological activity (bait-lamina test) were determined 12 to 18 months after OMW application. The results showed elevated K
+ contents in all treatments, but all other soil properties of winter treatments were comparable to the control, which suggested a certain recovery potential of the soil when OMW is applied in winter. By contrast, summer treatments revealed a ten-fold higher soil water repellency, a three-times lower biological activity, and a four-fold higher content of phenolic compounds, independently of whether the soil was kept moist by irrigation or not. Thus, the OMW constituents were neither degraded nor leached by winter rain when applied during the hot season. Further research is needed to distinguish leaching and biodegradation effects, and to understand the development of the composition and degradation kinetics of organic OMW constituents. [ABSTRACT FROM AUTHOR]- Published
- 2015
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22. Restructuring of a Peat in Interaction with Multivalent Cations: Effect of Cation Type and Aging Time.
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Kunhi Mouvenchery, Yamuna, Jaeger, Alexander, Aquino, Adelia J. A., Tunega, Daniel, Diehl, Dörte, Bertmer, Marko, and Schaumann, Gabriele Ellen
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HUMUS ,CATIONS ,MULTIVALENT molecules ,PEAT ,SORPTION ,SOIL chemistry ,BIOGEOCHEMISTRY - Abstract
It is assumed to be common knowledge that multivalent cations cross-link soil organic matter (SOM) molecules via cation bridges (CaB). The concept has not been explicitly demonstrated in solid SOM by targeted experiments, yet. Therefore, the requirements for and characteristics of CaB remain unidentified. In this study, a combined experimental and molecular modeling approach was adopted to investigate the interaction of cations on a peat OM from physicochemical perspective. Before treatment with salt solutions of Al
3+ , Ca2+ or Na+ , respectively, the original exchangeable cations were removed using cation exchange resin. Cation treatment was conducted at two different values of pH prior to adjusting pH to 4.1. Cation sorption is slower (>>2 h) than deprotonation of functional groups (<2 h) and was described by a Langmuir model. The maximum uptake increased with pH of cation addition and decreased with increasing cation valency. Sorption coefficients were similar for all cations and at both pH. This contradicts the general expectations for electrostatic interactions, suggesting that not only the interaction chemistry but also spatial distribution of functional groups in OM determines binding of cations in this peat. The reaction of contact angle, matrix rigidity due to water molecule bridges (WaMB) and molecular mobility of water (NMR analysis) suggested that cross-linking via CaB has low relevance in this peat. This unexpected finding is probably due to the low cation exchange capacity, resulting in low abundance of charged functionalities. Molecular modeling demonstrates that large average distances between functionalities (∼3 nm in this peat) cannot be bridged by CaB-WaMB associations. However, aging strongly increased matrix rigidity, suggesting successive increase of WaMB size to connect functionalities and thus increasing degree of cross-linking by CaB-WaMB associations. Results thus demonstrated that the physicochemical structure of OM is decisive for CaB and aging-induced structural reorganisation can enhance cross-link formation. [ABSTRACT FROM AUTHOR]- Published
- 2013
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23. Kinetics of the release of dissolved organic matter (DOM) from air-dried and pre-moistened soil material.
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Schaumann, Gabriele Ellen, Siewert, Christian, and Marschner, Bernd
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- 2000
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24. Toward Balancing the Pros and Cons of Spreading Olive Mill Wastewater in Irrigated Olive Orchards.
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Kurtz, Markus Peter, Dag, Arnon, Zipori, Isaac, Laor, Yael, Buchmann, Christian, Saadi, Ibrahim, Medina, Shlomit, Raviv, Michael, Zchori-Fein, Einat, Schaumann, Gabriele Ellen, Diehl, Dörte, Villasclaras, Sebastián Sánchez, and Martín, Juan Francisco García
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OLIVE ,SOIL moisture ,SOIL biology ,SEWAGE ,ARID regions - Abstract
The controlled application of olive mill wastewater (OMW) as a by-product of the olive oil extraction process is widespread in olive oil-producing countries. Therefore, a sustainable approach necessarily targets the positive effects of soil resilience between successive annual applications to exclude possible accumulations of negative consequences. To investigate this, we applied 50, 100, 100 with tillage and 150 m
3 OMW ha−1 y−1 for five consecutive seasons to an olive orchard in a semi-arid region and monitored various soil physicochemical and biological properties. OMW increased soil water content with concentration of total phenols, cations, and anions as well as various biological and soil organic matter indices. Soil hydrophobicity, as measured by water drop penetration time (WDPT), was found to be predominantly in the uppermost layer (0–3 and 3–10 cm). OMW positively affected soil biology, increased the activity and abundance of soil arthropods, and served as a food source for bacteria and fungi. Subsequent shallow tillage reduced the extent of OMW-induced changes and could provide a simple means of OMW dilution and effect minimization. Despite potentially higher leaching risks, an OMW dose of 50–100 m3 ha−1 applied every two years followed by tillage could be a cost-effective and feasible strategy for OMW recycling. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
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25. Analytical strategies to the determination of metal-containing nanoparticles in environmental waters.
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Leopold, Kerstin, Philippe, Allan, Wörle, Katharina, and Schaumann, Gabriele Ellen
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METAL nanoparticles , *EMERGING contaminants , *SOLID phase extraction , *ATOMIC absorption spectroscopy , *HYDRODYNAMICS - Abstract
Metal-containing nanoparticles (MNPs) represent emerging pollutants that still pose analytical challenges for their determination in environmentally relevant samples, including extremely low MNPs' concentrations, high colloidal background and the need to perform speciation analysis. Complementary to traditional state-of-the-art techniques evaluated elsewhere, this review additionally evaluates less conventional approaches for sample pretreatment, preconcentration, on- and offline detection, size characterisation and quantification of MNPs in environmental samples. Preconcentration techniques, like cloud point extraction and solid phase extraction, provide high preconcentration factors and recoveries. Electrothermal atomic absorption spectrometry opens interesting perspectives in the still unresolved distinction between dissolved ions and nanoparticles. Combination of single particle ICP-MS with size fractionation techniques, like hydrodynamic chromatography or electrospray-differential mobility analysis, is highly promising for assessment of shape and structure-related information of MNPs and their aggregates. Although highly relevant, the validation and production of reference materials and quantitative criteria on measurement certainty still require further development. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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26. Plastic mulching in agriculture. Trading short-term agronomic benefits for long-term soil degradation?
- Author
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Steinmetz, Zacharias, Wollmann, Claudia, Schaefer, Miriam, Buchmann, Christian, David, Jan, Tröger, Josephine, Muñoz, Katherine, Frör, Oliver, and Schaumann, Gabriele Ellen
- Subjects
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SOIL degradation , *PLASTIC mulching , *AGRICULTURE , *ENVIRONMENTAL impact analysis , *WATER efficiency - Abstract
Plastic mulching has become a globally applied agricultural practice for its instant economic benefits such as higher yields, earlier harvests, improved fruit quality and increased water-use efficiency. However, knowledge of the sustainability of plastic mulching remains vague in terms of both an environmental and agronomic perspective. This review critically discusses the current understanding of the environmental impact of plastic mulch use by linking knowledge of agricultural benefits and research on the life cycle of plastic mulches with direct and indirect implications for long-term soil quality and ecosystem services. Adverse effects may arise from plastic additives, enhanced pesticide runoff and plastic residues likely to fragment into microplastics but remaining chemically intact and accumulating in soil where they can successively sorb agrochemicals. The quantification of microplastics in soil remains challenging due to the lack of appropriate analytical techniques. The cost and effort of recovering and recycling used mulching films may offset the aforementioned benefits in the long term. However, comparative and long-term agronomic assessments have not yet been conducted. Furthermore, plastic mulches have the potential to alter soil quality by shifting the edaphic biocoenosis (e.g. towards mycotoxigenic fungi), accelerate C/N metabolism eventually depleting soil organic matter stocks, increase soil water repellency and favour the release of greenhouse gases. A substantial process understanding of the interactions between the soil microclimate, water supply and biological activity under plastic mulches is still lacking but required to estimate potential risks for long-term soil quality. Currently, farmers mostly base their decision to apply plastic mulches rather on expected short-term benefits than on the consideration of long-term consequences. Future interdisciplinary research should therefore gain a deeper understanding of the incentives for farmers and public perception from both a psychological and economic perspective in order to develop new support strategies for the transition into a more environment-friendly food production. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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27. Spatiotemporal distribution of silver and silver-containing nanoparticles in a prealpine lake in relation to the discharge from a wastewater treatment plant.
- Author
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Vogt, Roland, Mozhayeva, Darya, Steinhoff, Benedikt, Schardt, Annika, Spelz, Bastian Thiedo Frederic, Philippe, Allan, Kurtz, Sandra, Schaumann, Gabriele Ellen, Engelhard, Carsten, Schönherr, Holger, Lamatsch, Dunja Katharina, and Wanzenböck, Josef
- Abstract
Over two years we assessed silver-containing nanoparticles (SCN) and total silver in the in- and effluent of a wastewater treatment plant (WWTP) discharging purified wastewater into a lake. Additionally, total silver was measured in sludge of the WWTP and in water, sediment, and fish of the receiving lake at several points with varying distance to the discharge point and compared to a reference lake. We used a novel single particle inductively coupled plasma mass spectrometry (SP-ICP-MS, with microsecond time resolution) protocol to detect SCN in environmental samples in addition to total elemental analysis by ICP-MS/OES (optical emission spectrometry), and histological analysis by dark-field microscopy. Total silver was below the limit of quantification in the WWTP influent and effluent, and in lake water and fishes, except for one influent sample. However, comparably high silver concentrations were detected in the sludge, irrespective of the season, indicating accumulation of silver. Furthermore, SP-ICP-MS analysis of influent samples confirmed the presence of SCN. Despite the high removal efficiency of silver and SCN from the wastewater, high silver concentrations were measured in the sediment near the discharge point, suggesting a constant silver input into the lake. Silver and SCN levels were lower than concentrations leading to adverse effects in recently published toxicological studies, thus the investigated lake ecosystem is currently not at risk. Unlabelled Image • A novel SP-ICP-MS with μs-time resolution was applied for environmental samples. • Silver-containing nanoparticles (SCN) were detected in wastewater samples. • No seasonal variations of SCN concentrations were detected in the wastewater. • Total silver concentrations were low in wastewater, sludge, lake water, and sediments. • Wastewater discharge leads to silver accumulation in sediments near discharge area. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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28. Wechselwirkungen zwischen organischer Bodensubstanz und Wasser unter besonderer Berücksichtigung des Glasübergangsverhaltens
- Author
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Hurraß, Julia, Schaumann, Gabriele Ellen, and Technische Universität Berlin, Fakultät III - Prozesswissenschaften
- Subjects
ddc:500 - Abstract
Viele ökologisch wichtige Aspekte der organischen Bodensubstanz (OBS), wie die Sorption von organischen Verbindungen und die Wasseraufnahme-Kinetik, lassen sich nur mit Hilfe einer makromolekularen Betrachtungsweise der humosen Substanzen erklären. Es ist bekannt, dass die Konformation des makromolekularen OBS-Netzwerks stark vom Wasserstatus des Bodens beeinflusst wird. Die zugrunde liegenden Prozesse, wie die Art der Wasserbindung und die daraus resultierenden Effekte für die Starrheit der organischen Bodenmatrix, werden bisher jedoch nur unzureichend verstanden. Im Mittelpunkt dieser Dissertation stand die Charakterisierung der Wechselwirkungen zwischen der festen OBS und Wasser. Einerseits wurde der Wasseraufnahmeprozess humoser Bodenproben untersucht. Dabei wurden vor allem Unterschiede des Benetzungsvorgangs zwischen wasserabweisenden und benetzbaren Proben und mögliche Einflussfaktoren für Benetzungshemmung im Boden betrachtet. Andererseits wurde für 102 Bodenproben von unterschiedlichen Standorten das Glasübergangsverhalten der OBS, das sehr genau die Art der Wasserbindung widerspiegelt, untersucht. Sowohl die Ergebnisse der Benetzungsversuche als auch die der Glasübergangsuntersuchungen stützen die makromolekulare Vorstellungsweise der humosen Substanzen. In 52 der 102 Bodenproben wurden zwei Arten von Glasübergängen festgestellt: Ein klassischer Glasübergang lässt sich nur in wasserfreien Proben beobachten. Der andere Übergangstyp ist stark vom Wasserstatus der OBS abhängig und zeichnet sich durch einen nur langsam reversierenden Charakter aus, was der klassischen Definition von Glasübergängen widerspricht. Die Übergangstemperaturen dieses untypischen Übergangs lagen für alle untersuchten luftgetrockneten Proben zwischen 51 °C und 67 °C. Gemäß des Wasserstoffbrückenbindungs-Modells (HBCL) kann eine Quervernetzung der Seitenketten der organischen Substanzen durch mittels Wasserstoffbrücken gebundene Wassermoleküle die vergleichbare Starrheit und damit die ähnlichen Übergangstemperaturen der OBS luftgetrockneter Proben erklären. Zusätzlich zum Wasserstatus beeinflussen der Corg-Gehalt, die Profiltiefe und anthropogene Bodenveränderungen den untypischen glasübergangsähnlichen Stufenübergang. Aufgrund von Alterungsprozessen stellt die Zeit einen weiteren wichtigen Faktor dar. Die Alterungsprozesse können eine zunehmende Starrheit der organischen Bodenmatrix im Verlauf der Zeit verursachen und beruhen auf Konformationsänderungen der OBS, die stark von den Effekten der Wassermoleküle auf die makromolekulare Struktur abhängen. Höchstwahrscheinlich sind auch langsame Konformationsänderungen an den OBS-Oberflächen für den langsamen Benetzungsprozess von wasserabweisenden Proben, der bis zu drei Wochen dauern kann, verantwortlich. Die Ergebnisse dieser Arbeit zeigen, dass die Mechanismen, die für das wasserabweisende Verhalten verantwortlich sind, von Standort zu Standort variieren können. Für einen der beiden untersuchten anthropogen beeinflussten Standorte ist das Auftreten benetzungsgehemmter Bereiche mit niedrigen pH-Werten und hohen Leitfähigkeiten der Bodenlösung verbunden. Die Protonierung negativ geladener funktioneller Gruppen und eine stärker kondensierte OBS-Struktur aufgrund der hohen Elektrolytgehalte können die schlechte Benetzbarkeit dieser Bereiche verursachen. Für beide Standorte wurden in wässrigen Extrakten von wasserabweisenden Proben geringere Oberflächenspannungen als für die benetzbaren Proben gemessen. Es kann folglich vermutet werden, dass amphiphile Substanzen für das Auftreten von benetzungsgehemmten Bereichen im Boden eine wichtige Rolle spielen. Several ecologically relevant aspects of soil organic matter (SOM), like the sorption of organic compounds and the water uptake kinetics, can only be explained in terms of the macromolecular structure of the humic substances. It is known that the conformation of the macromolecular SOM network is distinctly affected by the water status in soil. But, the underlying processes, as the way of water binding and the resulting effects on the rigidity of the organic soil matrix, are still insufficiently understood. This thesis focused on the characterization of the interactions between solid SOM and water. On the one hand, the hydration process of humous soil samples was studied. Especially, differences in the wetting process of water repellent and wettable samples and possible factors of influence for soil water repellency were investigated. On the other hand, the glass transition behavior of SOM, which sensitively reflects the way of water bonding, was examined for a set of 102 soil samples from different locations. The results of the wetting experiments as well as of the study of the glass transition behavior strongly support the macromolecular view of humic substances. In 52 out of the 102 soil samples, two types of glass transitions were detected: A classical glass transition can be observed only in water-free samples. The other transition type is strongly influenced by the moisture status in SOM and reveals a slowly reversing behavior, which contradicts the classical definition of glass transitions. The transition temperatures of this atypical transition ranged between 51 °C and 67 °C for all studied air-dried samples. According to the hydrogen bond-based crosslinking (HBCL) model, a crosslinking of the side chains of the organic substances by hydrogen bond water molecules may explain the comparable rigidity and with that the similar transition temperatures of SOM in air-dried samples. In addition to the water status, the atypical glass transition-like step transition is influenced by the Corg content, the profile depth, and by anthropogenic impacts to the soil. Due to aging effects, the time additionally represents an important factor. These aging effects may cause an increasing rigidity of the organic soil matrix in the course of time and are based on conformational changes of SOM, which are distinctly influenced by the effects of water molecules on the macromolecular structure. Most probably, slow conformational changes occurring at the SOM surfaces are also responsible for the slow wetting process of water repellent samples, which may last up to three weeks. The results of this study indicate that the mechanisms causing water repellent behavior may differ from location to location. For one of the two studied anthropogenic sites, the occurrence of water repellent regions is correlated to low pH and high ionic strength in the soil solutions. The protonation of negatively charged functional groups and a more condensed SOM structure due to the high electrolyte contents may cause the lower wettability of these regions. For both locations, lower surface tensions were measured in aqueous extracts of actually water repellent samples than for actually wettable samples. Amphiphilic substances consequently are supposed to play an important part for the occurrence of water repellent spots in soil.
- Published
- 2006
29. Natural TiO 2 -Nanoparticles in Soils: A Review on Current and Potential Extraction Methods.
- Author
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Campos DA, Schaumann GE, and Philippe A
- Abstract
The monitoring of anthropogenic TiO
2 -nanoparticles in soils is challenged by the knowledge gap on their characteristics of the large natural TiO2 -nanoparticle pool. Currently, no efficient method is available for characterizing natural TiO2 -nanoparticles in soils without an extraction procedure. Considering the reported diversity of extraction methods, the following article reviews and discusses their potential for TiO2 from soils, focusing on the selectivity and the applicability to complex samples. It is imperative to develop a preparative step reducing analytical interferences and producing a stable colloidal dispersion. It is suggested that an oxidative treatment, followed by alkaline conditioning and the application of dispersive agents, achieve such task. This enables the further separation and characterization through size or surface-based separation (i.e., hydrodynamic fractionation methods, filtration or sequential centrifugation). Meanwhile, cloud point extraction, gel electrophoresis, and electrophoretic deposition have been studied on various nanoparticles but not on TiO2 -nanoparticles. Furthermore, industrially applied methods in, for example, kaolin processing (flotation and flocculation) are interesting but require further improvements on terms of selectivity and applicability to soil samples. Overall, none of the current extraction methods is sufficient toward TiO2 ; however, further optimization or combination of orthogonal techniques could help reaching a fair selectivity toward TiO2 .- Published
- 2020
- Full Text
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