TY - GEN A1 - Ahmed, Ashour A. A1 - Gypser, Stella A1 - Leinweber, Peter A1 - Freese, Dirk A1 - Kühn, Oliver T1 - New insights into IR spectroscopic characterization of phosphate binding at the goethite-water interface T2 - IPW9, ETH Zurich, Switzerland, 8-12 July, 2019 - Abstracts N2 - Facing the projected peak phosphorus (P) scenario, substantial research activities have been triggered to improve our knowledge towards a more efficient and sustainable use of P resources. One major factor playing a role in the P immobilization and thus its availability for plants is the strong interaction between phosphates and soil mineral surfaces, such as Fe- and Al-(oxyhydr)oxides. The reactions of phosphates with Fe-hydroxides and especially goethite have been studied extensively. But a molecular-level picture of the phosphate binding mechanism at the goethite-water interface is still lacking. Therefore, in the current contribution we have explored the molecular binding mechanism for the adsorbed phosphate at the goethite–water interface by performing sorption kinetics experiments for orthophosphate and characterizing the adsorbed species by FT-IR spectroscopy. In parallel, periodic quantum mechanical calculations, at the density functional theory (DFT) level, have been performed to explore the interaction mechanism as well as to calculate the IR spectra for monodentate (M) and bidentate (B) orthophosphate complexes with goethite at two different goethite surface planes (010 and 100) in the presence of water. In general, our interaction energy results give evidence that the mono-protonated B phosphate complex is more favored to be formed at the goethite–water interface although the M motif could exist as a minor fraction. Moreover, it was found that water plays an important role in controlling the phosphate adsorption process at the goethite surfaces. The interfacial water molecules form H-bonds (HBs) with the phosphate as well as with the goethite surface atoms. Further, some water molecules form covalent bonds with goethite Fe atoms while others dissociate at the surface to protons and hydroxyl groups. The present theoretical assignment of IR spectra introduces a benchmark for characterizing experimental IR data for the adsorbed KH2PO4 species at the goethite–water interface. In particular, IR spectra of the mono-protonated (2O+1Fe) B complex at the 010 goethite surface plane and the M complex at the 100 goethite surface plane were found to be consistent with the experimental data. In order to explore the role of different abundancies of surface planes and binding motifs, IR spectra obtained from weighted averages have been analyzed. Results confirmed the above conclusions drawn from interaction energy calculations. Moreover, the soil solution pH effect on the phosphate binding mechanism to goethite surface has been explored as well. Y1 - 2019 UR - https://pure.au.dk/portal/files/159039284/IPW9_AbstractBook.pdf SP - 108 CY - Zürich ER - TY - CHAP A1 - Koch, Maximilian A1 - Kruse, Jens A1 - Eichler-Löbermann, Bettina A1 - Gypser, Stella A1 - Flavel, R. A1 - Guppy, Christopher A1 - Zimmer, Dana A1 - Leinweber, Peter A1 - Siebers, Nina T1 - Phosphorus bioavailability in soil profiles of a long-term fertilizer experiment: The evaluation of their bioaccessibility T2 - Abstracts der DBG Jahrestagung 2017, 02.-07. Sept. 2017, Göttingen N2 - Global agricultural productivity depends on the use of finite phosphorus (P) resources of which not only the topsoil, but also subsoil, can hold immense reserves. To assess potential soil contribution to plant nutrition, we compared the P status of Stagnic Cambisol profiles in experimental plots that received different P fertilizer applications (control, triple superphosphate (TSP), compost, compost+TSP) for 16 years. Sequential fractionation was combined with P K-edge X-ray absorption near edge structure (XANES) spectroscopy to identify the chemical P speciation. Fertilized topsoils (21 to 69 kg P ha-1 a-1) showed P reserves larger by a factor of 1.2 to 1.4, and subsoil P reserves larger by a factor of 1.3 to 1.5 than those of the control. P-XANES revealed the predominance of inorganic P species such as moderately labile Fe- (46 to 92%), Al- (0 to 40%), and Ca- (0 to 15%) P compounds besides organic P (0 to 13%) in all treatments. The fertilizer application slightly altered P speciation throughout the profiles, but the type of fertilizer had no significant effect on it. Optimal plant growth requirements are restricted by the exchangeable P from the solid phase within the soil solution. Therefore, ongoing research focuses on the accessibility of P from P loaded amorphous Fe- and Al-hydroxides, previously identified as the predominant abiotic P forms. To assess their P desorption potential, P-33 rhizotron experiments combined with P-33 isotopic exchange kinetics (IEK) are underway. Preliminary results indicated that besides differences in P binding capacity of soil hydroxides, physical soil parameters, such as the matric potential, strongly control soil P availability, thus plant P acquisition rates can vary among different soil types. Our results gained new detailed information about P bioavailability under agricultural practice. The investigations towards P bioaccessibility may contribute to improved interpretation of soil P tests and reduced fertilizer recommendations. Y1 - 2017 UR - https://eprints.dbges.de/1595/ ER - TY - CHAP A1 - Gypser, Stella A1 - Veste, Maik ED - Novák, Martin ED - Krám, Pavel ED - Stepánová, M. T1 - Biological soil crusts as driver for ecosystem structures and functions on reclaimed post-mining sites in Lower Lusatia, Germany T2 - 9th International Symposium on Ecosystem Behavior BIOGEOMON, Litomysl, Czech Republic, August 20-24, 2017 Y1 - 2017 UR - http://www.biogeomon.cz/documents/Abstracts.pdf SP - 33 EP - 34 ER - TY - CHAP A1 - Gypser, Stella A1 - Slazak, Anna A1 - Freese, Dirk ED - Novák, Martin ED - Krám, Pavel ED - Stepánová, M. T1 - Impact of crystallization of iron and aluminium hydroxides on the mechanisms of phosphate binding T2 - 9th International Symposium on Ecosystem Behavior BIOGEOMON, Litomysl, Czech Republic, August 20-24, 2017 Y1 - 2017 UR - http://www.biogeomon.cz/documents/Abstracts.pdf SP - 366 EP - 367 ER - TY - CHAP A1 - Gypser, Stella A1 - Veste, Maik T1 - Application of chlorophyll fluorescence, CO2 gas exchange, and NDVI for the detection of spatial variances of photosynthesis of biological soil crusts on anthropogenic degraded soils T2 - 3rd International Workshop on Biological Soil Crusts BIOCRUST3, September 26-30, 2016, Star Hall-Moab, Utah, USA N2 - Degradation of soils and the destruction of vegetation as a result of anthropogenic disturbances affect ecosystem functions and properties worldwide. In Brandenburg (NE Germany) various ecosystems were degraded by different human activities like surface mining and military activities on sand dunes. These resulted in degraded open landscapes with an initial soil development. These new ecosystems are characterized by a high vulnerability to erosion, low water holding capacity, lack of nutrients, or low pH. For rehabilitation of degraded soils and vegetation, these post-mining and mobile sand dunes need specific restoration measures, but beside inappropriate soil characteristics, insufficient water availability can limit plant growth. Even located in the temperate zone of Europe, Brandenburg belongs to the driest regions in Germany and faces long drought periods. In this context, the determination of the influence of biocrusts on carbon accumulation during initial ecosystem succession, small-scale investigations on photosynthetic capacity and active phase regarding biocrust formation and developmental stage, which vary from initial green algae-crusts to biocrusts dominated by soil lichens or mosses, are necessary. Hence, succession of biocrusts result in a spatiotemporal heterogeneity and distribution pattern. We could show that varying species abundance, composition, and crust succession affect photosynthetic capacity, and hence, carbon fixation capability. Different spatial hotspots could be analyzed under field conditions and monitored during the season. Long-term measurements of climatic parameters, which include radiation, temperature, precipitation, and desiccation of biocrusts, will be linked to photosynthetic performances under lab conditions. This spatial model can help to understand the impact of biocrusts on carbon accumulation in initial soils. Due to the potential to colonize soil surface under harsh conditions without human support, advantages of biocrusts can be used systematically as a supporting rehabilitation measure for physical stabilization, gain of organic carbon, and hence, facilitates the growth of indigenous vegetation during primary succession. Y1 - 2016 UR - http://www.nau.edu/uploadedFiles/Centers-Institutes/Merriam-Powell/BioCrust3/_Forms/Compiled%20BioCrust3%20abstracts_Oct%2027.pdf SP - 24 EP - 25 ER - TY - GEN A1 - Gypser, Stella A1 - Veste, Maik ED - Thiede, Julia ED - Klein-Rauthake, Theresa T1 - Importance of P limitation for the C:N:P ratio in Robinia plantations on marginal sites T2 - GfÖ 2019, Science Meets Practice, 49th Annual Meeting of the Ecological Society of Germany, Austria and Switzerland, university of Münster, 9-13 September 2019 N2 - Due to disturbances of soils after open-cast lignite mining activities in the Lusatian mining district, Northeast Germany, large areas covered with excavated and dumped material. These initial soils are characterized by a lack of nutrients and organic matter which is why Robinia pseudoacacia was established during reclamation of those marginal sites. As a pioneer species, Robinia is well suitable for the establishment on reclaimed forest ecosystems due to the N fixation capability and its ability to grow on a nutrient-poor sandy substrate with low water holding capacity. Since the N requirement of the Robinia can be covered by symbiotic nodule bacteria, P is important as a growth-limiting nutrient. Even though the total and available P in soils increased with the age of the plantings (planted between 1995 and 2007), the ratio of available to total P decreased relative to younger plantings. Despite the accumulation of organic matter and the decomposition of organic bound P, the bioavailability is affected by ad- and desorption processes, especially on Fe- and Al-hydroxides. It was hypothesized that the P demand of young trees, initially provided by a one-time fertilizer application, exceeds the P supply by mineralization over time. As a first step, kinetics of P desorption from synthetic Fe- and Al-hydroxides were characterized by using humic acid as a model organic compound, to detect fast and slow releasable P over time. At the Robinia sites, soil samples were examined at different depth with regard to their C, N and P concentrations. From the first results, we can conclude that the P availability and its limitation influences the growth performance of Robinia as well as the N-fixing symbiotic bacteria and, thus, the C:N:P ratio as a long-term effect on an ecosystem scale. Y1 - 2019 UR - https://www.gfoe-conference.de/WEBS/GFOe2019.pages.download/Book_of_Abstracts2019.pdf SP - 82 ER - TY - GEN A1 - Veste, Maik A1 - Gypser, Stella T1 - Ökologische Funktionen und Dienstleistungen biologischer Bodenkrusten in Offenlandschaften - Fluch oder Segen? T2 - GfÖ 2019, Science Meets Practice, 49th Annual Meeting of the Ecological Society of Germany, Austria and Switzerland, university of Münster, 9-13 September 2019 N2 - Initiale und nährstoffarme Ökosysteme wie Grasländer und Offenlandschaften haben aus Sicht des Naturschutzes einen hohen Wert für die Landschaft und sind in der intensiv genutzten Kulturlandschaft Mitteleuropas selten geworden. Gerade Bergbaufolgelandschaften, aber auch gestörte Binnendünen, bieten Potenzial für die Entwicklung von initialen Lebensräumen und Landschaften. Die obersten Millimeter der Bodenoberfläche dieser Ökosysteme werden durch Biokrusten besiedelt. Gebildet werden diese komplexen Lebensgemeinschaften aus einer Vielzahl von Cyanobakterien, Grünalgen, Moosen, Pilzen, Bakterien und Flechten. Diese Organismen „verkleben“ die Bodenoberfläche und beeinflussen als „Ökosystem en miniature“ maßgeblich die ökosystemaren Prozesse und die weitere Vegetationsentwicklung. Der Eintrag von C und N sowie die Akkumulation von organischem Material fördert die Bodenentwicklung in der initialen Phase. Während der Sukzession der Biokrusten entwickeln sich die komplexen biotischen Prozesse des N-Kreislaufes mit Rückkopplungen auf die Nährstoffversorgung. Ausgeschiedene Exopolysaccharide, die eine Verbindung mit den Bodenpartikeln eingehen, verkleinern nach Regen den Porenraum der Bodenoberfläche und vermindern die Infiltration. Besonders Moos- und Flechten-Krusten unterbinden bei geringen Niederschlagsintensitäten die Infiltration in tiefere Bodenschichten. Konkurrenz und die großflächige Versiegelung der Bodenoberfläche haben zudem negative Auswirkungen auf die Keimung und Etablierung von höheren Pflanzen. Diese biotischen Interaktionen führen bei gesteuerten Sukzessionen auf Renaturierungsflächen zu Änderungen der Vegetationsentwicklung. Somit wird die Bedeutung der Biokrusten für die Renaturierungsökologie z.T. kontrovers diskutiert. Klein- und großräumige Störungen hingegen sind als integraler Bestandteil der Ökosystementwicklung einzuschließen. Y1 - 2019 UR - https://www.gfoe-conference.de/WEBS/GFOe2019.pages.download/Book_of_Abstracts2019.pdf SP - 166 CY - Münster ER - TY - CHAP A1 - Halke, Christian A1 - Gypser, Stella A1 - Mantovani, Dario A1 - Lebzien, Stefan A1 - Freese, Dirk A1 - Veste, Maik ED - Jeltsch, Florian ED - Joshi, Jasmin T1 - Yield, transpiration and growth of the new bioenergy crop IGNISCUM Candy under different water regimes T2 - GfÖ 43rd Annual Meeting, Building bridges in ecology, linking systems, scales and disciplines, September 9 to 13, 2013, Potsdam, Germany N2 - There is a growing global need to produce more energy and reducing greenhouse gas emissions. One possible source of renewable energy in parts of Europe is the use of crop for bioenergy production. Currently, maize dominates the biogas production. For a diversified production of substrates alternative crops needs to be evaluated for their sustainable utilization and ecological integration into agro-systems. The new bioenergy plants IGNISCUM Candy and IGNISCUM Basic are cultivars of the Sakhalin Knotweed (Fallopia sachalinensis, Fam. Polygonaceae), which are characterized by a high annual biomass production. Information on the crop production of this species is rare. Hence, understanding plant response to the combinations of water and nutrients availability is crucial for the development of sustainable plant production. In greenhouse experiments we investigate the interrelations between nutrient supply, biomass production, and plant ecophysiology. For the determination of yield-transpiration relations at whole plant level we used a wick lysimeter system, which allows us to study plant growth under controlled water regimes and to calculate the plant transpiration. The irrigation is supplied by an automatic drip irrigation system and computer-controlled in relation to the volumetric soil water content. Four different water treatments associated to the SWC range from well-watered to drought stressed plants. The influence of plant sizes on plant water use was investigated under different nitrogen supply. The fertilizer applied is calcium ammonium nitrate (N) and the rates for the four treatments are 0, 50, 100, 150 kg N/ha at the beginning of the growing season. Plant transpiration is calculated on the basis of water input, storage and drainage in weekly intervals. The cumulative transpiration of the plants during the growing season is between 49 L (drought stressed) and 141 L (well-watered) per plant, respectively. We calculated a transpiration coefficient of 525 Liters per kg dry biomass. Y1 - 2013 UR - http://www.gfoe-2013.de/download/130905_GFOe_2013_Abstracts.small.pdf SP - 32 EP - 33 ER - TY - GEN A1 - Gypser, Stella A1 - Freese, Dirk T1 - Mobilization of P from crystalline and amorphous Fe- and Al-hydroxides T2 - EGU General Assembly 2020 KW - Phosphorus KW - Sorption KW - Hydroxides Y1 - 2020 U6 - https://doi.org/10.5194/egusphere-egu2020-2871 ER -