@misc{Fischer, author = {Fischer, Thomas}, title = {PCA-based Supervised Identification of Biological Soil Crusts in Multispectral Images}, series = {MethodsX}, volume = {6}, journal = {MethodsX}, issn = {2215-0161}, doi = {10.1016/j.mex.2019.03.013}, pages = {764 -- 772}, abstract = {It was the aim of the method development to classify types of various biological soil crusts (biocrusts) using principle component analysis (PCA) on multispectral images. To address this aim, visible (RGB) and NIR images of bare sandy soil, algal and moss biocrusts were registered, per channel reflection values were determined using a calibration color chart on a pixel basis, and a PCA was performed on the unfolded RGB-NIR reflectance hypercubes (i.e. three-dimensional hypercubes were transformed into x.y × λ 2D-matrices with λ channels serving as variables for PCA). The classification approach was based on the hypothesis that biocrust types map specifically in PCA ordination plots, meaning that distinct regions in ordination plots may be assigned specifically to individual biocrust types. Reallocation of the pixels assigned to biocrust types to their respective image coordinates would then yield biocrust classification plots. Allows manual selection of features or identification of given features in PCA ordination plots. Fully permits the selection of relevant and omission of irrelevant, as well as identification of unknown classes. It is not restricted to RGB-NIR multispectral data only, but may be applied to any type of multimodal imaging data.}, language = {en} } @misc{HinzHafarFischer, author = {Hinz, Christoph and Hafar, Brian and Fischer, Thomas}, title = {Heavy metal mobilisation of salt affected soils and sediments: Assessing the role of chloride complex formation.}, series = {European Geosciences Union, General Assembly 2019, Vienna, Austria, 7-12 April 2019}, journal = {European Geosciences Union, General Assembly 2019, Vienna, Austria, 7-12 April 2019}, address = {Katlenburg-Lindau}, abstract = {Terrestrial and aquatic ecosystems are increasingly exposed to high level of salt (NaCl) concentrations. Impacts of increased salt concentration on mobilisation of heavy metals have been shown for road side soils receiving de-icing salt, for sediments and soils exposed to salt water intrusions, and soils and aquifers receiving runoff from salt mines. In fact, this study was motivated by the impact of salt dumps on soil and groundwater observed for potash mines in the central part of Germany. The objectives of this contribution is to asses the impact of NaCl concentration on heavy metal mobilization using speciation modelling. In particular, we focus on the effect of chloride complex formation in solution and how strongly this complex formation is "extracting" heavy metal cation from soil and sediments substrates. As experimental data for speciation at very high ionic strength is not readily available and not easily measurable, we focus on PHREEQC modelling to assess NaCl concentration ranges up to 3 M, needing to employ Pitzer equation as the activity model. In order to determine the competition of surface reaction and complex formation in aqueous solution, we used three reaction models: i) surface complexation with a high and low affinity site for iron hydroxide, ii) a heterogeneous binding site model for humic acids and iii) ion exchange as described with Rothmund-Kornfeld equation We did a series of simulations for Zn, Cd and Pb. Species distribution for the aqueous phase and the solid surfaces where determined by increasing NaCl solutions for a given total heavy metal concentration. In nearly all simulations conducted, the difference between simulations allowing chloride complexes to form and simulations where complexation is disabled, showed the emergence of a characteristic concentration range of NaCl for which the effect of chloride complexation reaches a maximum. In general, the range of highest sensitivity concerning mobilization occurs within the range of 1-3M NaCl for all simulations. At the lower end of this range shows the highest sensitivity to NaCl changes and is determined by several factors including the affinity to bonding sites and the speciation of an element along the salinity gradient. The peak of this curve is controlled by the point along the salinity gradient where the majority of heavy metal has been mobilized from the surface phase. One important outcome of this study is, that increasing NaCl background concentration behaves in a nonlinear way that is determined by the heterogeneity of the surface binding sites and that there is no simple way of assessing the mobilization potential of chloride complexation in soils and sediments.}, language = {en} } @misc{KuhnJenschBryantetal., author = {Kuhn, Ramona and Jensch, Robert and Bryant, Isaac Mbir and Fischer, Thomas and Liebsch, Stephan and Martienssen, Marion}, title = {Rapid sample clean-up procedure for aminophosphonate determination by LC/MS analysis}, series = {Talanta}, volume = {208}, journal = {Talanta}, issn = {0039-9140}, doi = {10.1016/j.talanta.2019.120454}, pages = {6}, abstract = {Aminophosphonates are commonly utilised for complexing bivalent ions such as calcium and magnesium. With regard to environmental samples, the analysis of these highly polar compounds is still challenging due to matrix effects and lacking analytical standard methods. We have recently developed a LC/MS method for common aminophosphonates without derivatisation. This LC/MS method delivers precise and accurate measurement for standard samples with very low concentration of cations disturbing the analysis. However, due to matrix effects this LC/MS method requires a sample clean-up being also applicable to natural water or wastewater samples. We developed and optimised a sample clean-up procedure applying strong cation exchange resin Dowex 50WX8. This clean-up allows a single LC/MS analysis of hydroxyethelidene(diphosphonic acid) (HEDP), aminotris(methylenephosphonic acid) (ATMP), ethylenediaminetetra(methyloenephosphonic acid) (EDTMP), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP) and its major intermediates amino(methylphosphonic acid) (AMPA) and iminodi(methylenephosphonic acid) (IDMP). We compared different test conditions with six aminophosphonates in either ultra pure water or tap water. The latter was used to simulate cation concentrations typical for natural waters. To elute all aminophosphonate including AMPA, ammonium acetate addition was necessary. The addition of ammonium acetate was combinable with all tested aminophosphonates and provides high sample quality for LC/MS analysis. For acceptable recovery, the smallest aminophosphonate AMPA required the highest addition of ammonium acetate (1000 mg L-1) during the sample clean-up. Finally, the optimised clean-up procedure was successfully applied to identify and quantify phosphonates from an industrial wastewater sample. The sample clean-up procedure is simple, cheap, rapid and precise and can be further combined with solid phase extraction and more sensitive LC/MS methods.}, language = {en} } @misc{WannerBirkhoferFischeretal., author = {Wanner, Manfred and Birkhofer, Klaus and Fischer, Thomas and Shimizu, Miki and Shimano, Satoshi D. and Puppe, Daniel}, title = {Soil Testate Amoebae and Diatoms as Bioindicators of an Old Heavy Metal Contaminated Floodplain in Japan}, series = {Microbial Ecology}, volume = {79}, journal = {Microbial Ecology}, number = {1}, issn = {1432-184X}, doi = {10.1007/s00248-019- 01383-x}, pages = {123 -- 133}, language = {en} } @misc{KuhnJenschBryantetal., author = {Kuhn, Ramona and Jensch, Robert and Bryant, Isaac Mbir and Fischer, Thomas and Liebsch, Stephan and Martienssen, Marion}, title = {Photodegradation of ethylenediaminetetra(methylenephosphonic acid) - The effect of the system configuration}, series = {Journal of Photochemistry \& Photobiology A: Chemistry}, volume = {388}, journal = {Journal of Photochemistry \& Photobiology A: Chemistry}, issn = {1010-6030}, doi = {10.1016/j.jphotochem.2019.112192}, pages = {9}, abstract = {Photodegradation of aminophosphonates such as ethylenediaminetetra(methylenephosphonic acid) (EDTMP) is recently assumed being the major degradation pathway in aquatic environments. Several photolysis studies were reported about EDTMP and possible breakdown products occurring in natural ecosystems. Reliable prediction of environmental photolysis of parent compounds and possible release of breakdown products requires different set-up conditions and varying the parameters influencing the photodegradation. We studied the influence of three different system configurations during UV degradation of EDTMP. These three configurations differed either in geometry and/or treated sample volumes. System 1 was equipped with a direct cooling jacket at the UV lamp. System 2 had the geometry of system 1 but there was no usage of a direct cooling jacket. System 3 was a gas-tight system with a larger sample volume. Using the chemical actinometer potassium ferrioxalate, we determined the highest photon flux for system 3 followed by system 2 and 1. In addition, we performed scavenger experiments with methanol and ascorbic acid in order to prove the dominating radical species. In system 1, the addition of methanol showed almost no effect while the ascorbic acid resulted in a reduction of 57.1\% orthophosphate released. Therefore we conclude that in system 1 the radical-drive degradation of EDTMP is mainly based on superoxide radicals. In system 2 and 3 both radical species, i.e., hydroxyl radicals and superoxide radicals, contribute to the photodegradation of EDTMP. We determined different half-lives for EDTMP for the three different systems configurations. For system 1, the estimated half-life achieved was 14.09 ± 0.15 min. For system 2 and 3, the half-lives were almost similar and averaged 4.75 ± 0.05 min and 5.02 ± 0.20 min, respectively. Contrary to our assumption to also find the highest degradation rate for system 3, we found the highest degradation rate for system configuration 2 as a result of the differences in the construction and geometry of the three systems. Our findings lead us to recommend the three system configuration for different research purposes. Thus, we recommend system 1 for detailed studies on the degradation pathway of the parent compound and their breakdown products. System 2 is recommended as a suitable configuration for kinetic studies of the parent compound. And finally, we recommend the system configuration 3 for complete mass balances. The gas-tight system allows determining all soluble and gaseous compounds.}, language = {en} } @misc{ZhangMoreauGeyeretal., author = {Zhang, Tingyi and Moreau, Danielle J. and Geyer, Thomas and Fischer, Jeoffrey and Doolan, Con}, title = {Dataset on tip vortex formation noise produced by wall-mounted finite airfoils with flat and rounded tip geometries}, series = {Data in Brief}, volume = {28}, journal = {Data in Brief}, issn = {2352-3409}, doi = {10.1016/j.dib.2019.105058}, pages = {8}, language = {en} } @misc{ZhangMoreauGeyeretal., author = {Zhang, Tingyi and Moreau, Danielle J. and Geyer, Thomas and Fischer, Jeoffrey and Doolan, Con}, title = {Dataset on tip vortex formation noise produced by wall-mounted finite airfoils with sinusoidal and porous tip geometries}, series = {Data in Brief}, volume = {30}, journal = {Data in Brief}, issn = {2352-3409}, doi = {10.1016/j.dib.2020.105471}, pages = {10}, language = {en} } @misc{SchlykowManganelliRoemeretal., author = {Schlykow, Viktoria and Manganelli, Constanza Lucia and R{\"o}mer, Friedhard and Clausen, Caterina J. and Augel, Lion and Schulze, J{\"o}rg and Katzer, Jens and Schubert, Michael Andreas and Witzigmann, Bernd and Schroeder, Thomas and Capellini, Giovanni and Fischer, Inga Anita}, title = {Ge(Sn) nano-island/Si heterostructure photodetectors with plasmonic antennas}, series = {Nanotechnology}, volume = {31}, journal = {Nanotechnology}, number = {34}, issn = {1361-6528}, doi = {10.1088/1361-6528/ab91ef}, pages = {11}, language = {en} } @misc{ManzoniChakrawalFischeretal., author = {Manzoni, Stefano and Chakrawal, Arjun and Fischer, Thomas and Schimel, Joshua P. and Porporato, Amilcare and Vico, Giulia}, title = {Rainfall intensification increases the contribution of rewetting pulses to soil respiration}, series = {Biogeosciences}, volume = {17}, journal = {Biogeosciences}, number = {15}, doi = {10.5194/bg-17-4007-2020}, pages = {4007 -- 4023}, abstract = {Soil drying and wetting cycles promote carbon (C) release through large heterotrophic respiration pulses at rewetting, known as the "Birch" effect. Empirical evidence shows that drier conditions before rewetting and larger changes in soil moisture at rewetting cause larger respiration pulses. Because soil moisture varies in response to rainfall, these respiration pulses also depend on the random timing and intensity of precipitation. In addition to rewetting pulses, heterotrophic respiration continues during soil drying, eventually ceasing when soils are too dry to sustain microbial activity. The importance of respiration pulses in contributing to the overall soil heterotrophic respiration flux has been demonstrated empirically, but no theoretical investigation has so far evaluated how the relative contribution of these pulses may change along climatic gradients or as precipitation regimes shift in a given location. To fill this gap, we start by assuming that heterotrophic respiration rates during soil drying and pulses at rewetting can be treated as random variables dependent on soil moisture fluctuations, and we develop a stochastic model for soil heterotrophic respiration rates that analytically links the statistical properties of respiration to those of precipitation. Model results show that both the mean rewetting pulse respiration and the mean respiration during drying increase with increasing mean precipitation. However, the contribution of respiration pulses to the total heterotrophic respiration increases with decreasing precipitation frequency and to a lesser degree with decreasing precipitation depth, leading to an overall higher contribution of respiration pulses under future more intermittent and intense precipitation. Specifically, higher rainfall intermittency at constant total rainfall can increase the contribution of respiration pulses up to ∼10 \% or 20 \% of the total heterotrophic respiration in mineral and organic soils, respectively. Moreover, the variability of both components of soil heterotrophic respiration is also predicted to increase under these conditions. Therefore, with future more intermittent precipitation, respiration pulses and the associated nutrient release will intensify and become more variable, contributing more to soil biogeochemical cycling.}, language = {en} } @misc{JurischkaDinterEfimovaetal., author = {Jurischka, Christoph and Dinter, Franziska and Efimova, Anastasia and Weiss, Romano and Schiebel, Juliane and Schulz, Christian and Fayziev, Bekzodjon and Schierack, Peter and Fischer, Thomas and R{\"o}diger, Stefan}, title = {An explorative study of polymers for 3D printing of bioanalytical test systems}, series = {Clinical Hemorheology and Microcirculation}, volume = {75}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/CH-190713}, pages = {57 -- 84}, abstract = {Background: The 3D printing is relevant as a manufacturing technology of functional models for forensic, pharmaceutical and bioanalytical applications such as drug delivery systems, sample preparation and point-of-care tests. Objective: Melting behavior and autofluorescence of materials are decisive for optimal printing and applicability of the product which are influenced by varying unknown additives. Methods: We have produced devices for bioanalytical applications from commercially available thermoplastic polymers using a melt-layer process. We characterized them by differential scanning calorimetry, fluorescence spectroscopy and functional assays (DNA capture assay, model for cell adhesion, bacterial adhesion and biofilm formation test). Results: From 14 tested colored, transparent and black materials we found only deep black acrylonitrile-butadiene-styrene (ABS) and some black polylactic acid (PLA) useable for fluorescence-based assays, with low autofluorescence only in the short-wave range of 300-400 nm. PLA was suitable for standard bioanalytical purposes due to a glass transition temperature of approximately 60°C, resistance to common laboratory chemicals and easy print processing. For temperature-critical methods, such as hybridization reactions up to 90°C, ABS was better suited. Conclusions: Autofluorescence was not a disadvantage per se but can also be used as a reference signal in assays. The rapid development of individual protocols for sample processing and analysis required the availability of a material with consistent quality over time. For fluorescence-based assays, the use of commercial standard materials did not seem to meet this requirement.}, language = {en} } @misc{KrisponeitFischerEsseretal., author = {Krisponeit, Jon-Olaf and Fischer, Simon and Esser, Sven and Moshnyaga, Vasily and Schmidt, Thomas and Piper, Louis F. J. and Flege, Jan Ingo and Falta, Jens}, title = {The morphology of VO2/TiO2(001): terraces, facets, and cracks}, series = {Scientific Reports}, volume = {10}, journal = {Scientific Reports}, issn = {2045-2322}, doi = {10.1038/s41598-020-78584-9}, pages = {8}, abstract = {Vanadium dioxide (VO2) features a pronounced, thermally-driven metal-to-insulator transition at 340 K. Employing epitaxial stress on rutile TiO2(001) substrates, the transition can be tuned to occur close to room temperature. Striving for applications in oxide-electronic devices, the lateral homogeneity of such samples must be considered as an important prerequisite for efforts towards miniaturization. Moreover, the preparation of smooth surfaces is crucial for vertically stacked devices and, hence, the design of functional interfaces. Here, the surface morphology of VO2/TiO2(001) films was analyzed by low-energy electron microscopy and diffraction as well as scanning probe microscopy. The formation of large terraces could be achieved under temperature-induced annealing, but also the occurrence of facets was observed and characterized. Further, we report on quasi-periodic arrangements of crack defects which evolve due to thermal stress under cooling. While these might impair some applicational endeavours, they may also present crystallographically well-oriented nano-templates of bulk-like properties for advanced approaches.}, language = {en} } @misc{ZhangGeyerSilvaetal., author = {Zhang, Tingyi and Geyer, Thomas and Silva, Charitha de and Fischer, Jeoffrey and Doolan, Con and Moreau, Danielle J.}, title = {Experimental Investigation of Tip Vortex Formation Noise Produced by Wall-Mounted Finite Airfoils}, series = {Journal of Aerospace Engineering}, volume = {34}, journal = {Journal of Aerospace Engineering}, number = {6}, issn = {1943-5525}, doi = {10.1061/(ASCE)AS.1943-5525.0001315}, language = {en} } @misc{FranzenFischer, author = {Franzen, Christoph and Fischer, Thomas}, title = {Removal of Iron Crusts from Sandstone Sculptures in a Fountain}, series = {Environmental Earth Sciences}, volume = {81}, journal = {Environmental Earth Sciences}, number = {7}, issn = {1866-6299}, doi = {10.1007/s12665-022-10302-2}, language = {en} } @misc{KuhnJenschFischeretal., author = {Kuhn, Ramona and Jensch, Robert and Fischer, Thomas and Keuler, Klaus and Bryant, Isaac Mbir and Martienssen, Marion}, title = {Sunlight Degradation of the Aminophosphonate Diethylenetriamine Penta-(Methylenephosphonic Acid)}, series = {Solar}, volume = {2}, journal = {Solar}, number = {2}, issn = {2673-9941}, doi = {10.3390/solar2020009}, pages = {141 -- 157}, abstract = {Aminophosphonate diethylenetriamine penta(methylenephosphonic acid) (DTPMP) is a scale inhibitor commonly used in several industries. DTPMP is suspected to cause anthropogenic pollution through discharge into the aquatic environment. DTPMP is assumed to be degraded by sunlight radiation. We recently predicted a preliminary degradation pathway of DTPMP applyingUV treatment. Currently, we have not yet evidenced that DTPMP shows the same degradation pattern with natural sunlight. One major reason leads to the fact that the light spectrum emitted by UV lamps does not completely represent the natural sunlight spectrum, and the emitted UVB and UVA irradiation flux is much higher than for solar light. For that reason, the degradation pattern and kinetics might be different between artificial UV treatment and natural sunlight treatment. Here, we investigated whether DTPMP is degradable under natural sunlight radiation, and whether the degradation mechanisms determined through UV treatment are transferable to sunlight. We investigated five different treatment conditions, i.e., DTPMP degradation in direct or diffuse sunlight, in diffuse sunlight with addition of Ca2+ or Mg2+, and in diffuse sunlight with local TW. Our experiment was carried out from March 2021 to October 2021. We performed LC/MS analyses and measured the release of o-PO4 3 . DTPMP was degraded with all five treatment conditions. The fastest DTPMP degradation occurred in direct and diffuse sunlight without addition of bivalent cations. The addition of Ca2+ and Mg2+ resulted in inhibited degradation. Similar effects occurred for sunlight treatment with local TW. We evidenced different degradation mechanisms for DTPMP depending on the presence of alkaline earth metals as we previously proposed for UV-treated DTPMP. However, both degradation mechanisms of DTPMP belong to the same degradation pathway determined with UV treatment. Therefore, we conclude that DTPMP undergoes a similar degradation pathway in sunlight as compared to UV light.}, language = {en} } @misc{KidronFischerXiao, author = {Kidron, Giora J. and Fischer, Thomas and Xiao, Bo}, title = {The ambivalent effect of biocrusts on evaporation: Can the contradictory conclusions be explained? A review}, series = {Geoderma}, volume = {Vol. 416}, journal = {Geoderma}, issn = {1872-6259}, doi = {10.1016/j.geoderma.2022.115805}, pages = {13}, language = {en} } @misc{KidronLichnerFischeretal., author = {Kidron, Giora J. and Lichner, Lubomir and Fischer, Thomas and Starinsky, Abraham and Or, Dani}, title = {Mechanisms for biocrust-modulated runoff generation - A review}, series = {Earth-Science Reviews}, volume = {231}, journal = {Earth-Science Reviews}, issn = {0012-8252}, doi = {10.1016/j.earscirev.2022.104100}, pages = {1 -- 22}, language = {en} } @misc{FischerMarchettiDeschmannAssisetal., author = {Fischer, Thomas and Marchetti-Deschmann, Martina and Assis, Ana Cristina and Elad, Michal Levin and Algarra, Manuel and Barac, Marko and Bogdanovic Radovic, Iva and Cicconi, Flavio and Claes, Britt and Frascione, Nunzianda and George, Sony and Guedes, Alexandra and Heaton, Cameron and Heeren, Ron and Lasic, Violeta and Lerma, Jos{\´e} Luis and Valle Martinez de Yuso Garcia, Maria del and Nosko, Martin and O'Hara, John and Oshina, Ilze and Palucci, Antonio and Pawlaczyk, Aleksandra and Posp{\´i}škov{\´a}, Krist{\´y}na and de Puit, Marcel and Radodic, Ksenija and Rēpele, Māra and Ristova, Mimoza and Romolo, Francesco Saverio and Šafař{\´i}k, Ivo and Siketic, Zdravko and Spigulis, Janis and Szynkowska-Jozwik, Malgorzata Iwona and Tsiatsiuyeu, Andrei and Vella, Joanna and Dawson, Lorna and R{\"o}diger, Stefan and Francese, Simona}, title = {Profiling and imaging of forensic evidence - A pan-European forensic round robin study part 1: Document forgery}, series = {Science \& Justice}, volume = {62}, journal = {Science \& Justice}, number = {4}, issn = {1876-4452}, doi = {10.1016/j.scijus.2022.06.001}, pages = {433 -- 447}, language = {en} } @misc{BeckerStorckLiuetal., author = {Becker, L. and Storck, Peter and Liu, Y. and Schwalb, G. and Schroeder, Thomas and Fischer, Inga Anita and Albrecht, M.}, title = {Optimizing misfit dislocation glide kinetics for enhanced threading dislocation density reduction in Si1- xGex/Si (001) layers through dynamic growth rate control}, series = {Journal of Applied Physics}, volume = {135}, journal = {Journal of Applied Physics}, number = {20}, issn = {0021-8979}, doi = {10.1063/5.0204318}, pages = {10}, language = {en} } @misc{EissaFischerMausolfetal., author = {Eissa, Mohamed Hussein and Fischer, Gunter and Mausolf, Thomas and R{\"u}cker, Holger and Malignaggi, Andrea and Kahmen, Gerhard}, title = {220-320-GHz J-Band 4-Way Power Amplifier in Advanced 130-nm BiCMOS Technology}, series = {IEEE Microwave and Wireless Components Letters}, volume = {32}, journal = {IEEE Microwave and Wireless Components Letters}, number = {11}, issn = {1531-1309}, doi = {10.1109/LMWC.2022.3181407}, pages = {1335 -- 1338}, language = {en} } @misc{FischerVesteWieheetal., author = {Fischer, Thomas and Veste, Maik and Wiehe, Wolfgang and Lange, Philipp}, title = {How biological crusts are stabilizing the soil surface? The development of organo-mineral interactions in the initial phase}, series = {EGU General Assembly 2009, Vienna, Austria, 19 - 24 April 2009}, journal = {EGU General Assembly 2009, Vienna, Austria, 19 - 24 April 2009}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, language = {en} } @inproceedings{FischerVesteWieheetal., author = {Fischer, Thomas and Veste, Maik and Wiehe, Wolfgang and Lange, Philipp}, title = {Linking microstructural and spectroscopic analysis of biological soil crusts - investigation of organo-mineral interactions}, series = {6th International Symposium on Ecosystem Behaviour BIOGEOMON 2009}, booktitle = {6th International Symposium on Ecosystem Behaviour BIOGEOMON 2009}, editor = {Ukonmaanaho, Liisa and Nieminen, Tiina Maileena and Starr, Michael}, publisher = {Finnish Forest Research Institut}, address = {Vantaa, Finland}, isbn = {978-951-40-2177-0}, pages = {S. 412}, language = {en} } @misc{DuemigVesteHagedornetal., author = {D{\"u}mig, Alexander and Veste, Maik and Hagedorn, Frank and Fischer, Thomas and Lange, Philipp and Spr{\"o}te, Roland and K{\"o}gel-Knabner, Ingrid}, title = {Biological soil crusts on initial soils: organic carbon dynamics and chemistry under temperate climatic conditions}, series = {Biogeosciences Discussion}, volume = {10}, journal = {Biogeosciences Discussion}, number = {1}, issn = {1810-6285}, pages = {851 -- 894}, language = {en} } @misc{DuemigVesteHagedornetal., author = {D{\"u}mig, Alexander and Veste, Maik and Hagedorn, Frank and Fischer, Thomas and Lange, Philipp and Spr{\"o}te, Roland and K{\"o}gel-Knabner, Ingrid}, title = {Organic matter from biological soil crusts induces the initial formation of sandy temperate soils}, series = {Catena}, volume = {122}, journal = {Catena}, doi = {10.1016/j.catena.2014.06.011}, pages = {196 -- 208}, abstract = {Different development stages of algae-dominated and moss-dominated biological soil crusts (BSCs) were sampled on a natural sand dune (b17 years old) and on an experimental sand dune (b8 years old) along a catena, including gradients of vegetation cover, location on the slope, as well as composition and thickness of BSC organisms in northeastern Germany. The accumulation of BSC-derived organic carbon (OC)was determined for bulk materials and fractions less than 63 μm. The OC composition was characterized by solid-state 13C NMR spectroscopy and the carbohydrate-C signature. 14C contents were determined to assess the origin and dynamics of OC. From the radiocarbon contents, two OC pools were differentiated: recent BSC-derived and lignite-derived "old" OC. Downward movement of OC into the underlying substratewas found only undermoss-dominated BSCs at the old sand dune. BSC-derived OC was mainly composed of carbohydrate-C and, to a lesser extent, alkyl C and N-alkyl C, with considerably higher contributions of alkyl C in the young dune, indicating differences in the composition of extracellular polymeric substances produced by the BSCs with age. This is consistent with higher proportions of water-soluble OC of moss-dominated BSCs at the old dune, which is leached in the underlying substrate and initiates soil formation. Because of the channeling effect of mosses, OC depth translocation along with suspended colloidal substances contribute to OC accumulation in substrates.}, language = {en} }