TY - GEN A1 - Dietz, Miriam A1 - Küppers, Manfred A1 - Wachendorf, Magnus A1 - Stefan, Thorsten A1 - Veste, Maik A1 - Gypser, Stella T1 - Modelling photosynthesis and carbon fluxes of moss- and lichen-dominated biological soil crusts in temperate dry acid grasslands in Brandenburg 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 - Top soils in temperate climates are regularly covered by cryptogames. Depending on the climatic and environmental conditions and their development stage, these biocrusts are built up by different species of cyanobacteria, bacteria, green algae, mosses, liverworts, lichens and fungi, which crosslink the uppermost soil particles. Biocrusts create a thin surface layer of high biotic activity, with high C and nutrient pools and fluxes to deeper soil layers, where the soil tends to be biotically and biogeochemically less active. Changes in soil structure, e.g. due to the accumulation of organic material and the ability of biological nitrogen fixation, result in significant feedback and control of biogeochemical processes. We analysed the response of photosynthesis and respiration to changing temperature and light in two moss-and lichen-dominated soil crusts from a dry acid grassland in the vicinity of a pine forest in Brandenburg, Germany. For the estimation of carbon fluxes, we combined lab-based CO2 gas exchange measurements and continuous determination of biocrust drying and rewetting cycles under field conditions. These experiments facilitated the development of an empirical photosynthesis model that allows for an estimation of the carbon dynamics of biological soil crusts based on their ecophysiological performance. Y1 - 2019 UR - https://www.gfoe-conference.de/WEBS/GFOe2019.pages.download/Book_of_Abstracts2019.pdf SP - 223 CY - Münster ER - TY - GEN A1 - Gypser, Stella A1 - Diez, Miriam A1 - Boelli, Daniel A1 - Wachendorf, Magnus A1 - Küppers, Manfred A1 - Veste, Maik T1 - Monitoring of biocrust development and physiological activity in disturbed ecosystems in Central Europe T2 - Biocrust 4 - 4th International Workshop on Biological Soil Crusts N2 - In many ecosystems of the earth, biocrusts influence the successive development of vegetation through their influence on the soil formation. This change in soil structure, e.g. due to the accumulation of organic material and the ability of biological nitrogen fixation, results in significant feedback and controls of ecosystem processes, especially in arid regions. In Brandenburg, located in NE Germany, the dry grasslands on sand dunes and the post-mining landscapes, characterized by edaphic drought and lack of nutrients as well as disturbances, are ecologically interesting locations for investigations of the biocrusts. In recent years, the species composition, structure, N-fixation, C-fluxes, and accumulation as well as their soil hydrological properties of biocrusts have been characterized and ecophysiological measurements of biocrust activity and CO2 exchange of different biocrust types under standardized environmental conditions have been performed in the laboratory. These ecophysiological measurements were correlated for the first time with NDVI measurements using a modified consumer camera, thus enabling a spatial analysis of the photosynthesis hotspots and a transfer from the lab into the landscape. The development and physiological activity of biocrusts are significantly influenced by microclimatic boundary conditions and moisture-dry cycles. The duration of these moisture phases is decisive for their spatial and temporal development and for the differentiation of the developmental stages. The permanent recording of moisture in the biocrusts in the uppermost millimeters using a newly developed biocrust wetness sensor in combination with NDVI measurements enable detailed information about biocrust activities and carbon fluxes. These continuous measurements of NDVI and physiological activity with PRI sensors allows determining seasonal activity phases in relation to microclimatological site conditions. More recent technological developments in sensor technology make it possible to carry out detailed and cost-effective investigations of the biocrust activity over the course of the year. KW - biological soil crusts KW - physiological activity KW - ecosystem development Y1 - 2019 U6 - https://doi.org/10.13140/RG.2.2.11042.99523 VL - 2019 CY - North Stradbroke Island, Queensland , Australia ER - TY - GEN A1 - Gypser, Stella A1 - Veste, Maik T1 - Hotspot biocrusts: Combining chlorophyll fluorescence and NDVI to analyze spatial and temporal variations of photosynthesis 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 - Biological soil crusts (biocrusts) play an important role as pioneering organisms on initial soils and in open landscapes after natural and human disturbances. Even though they only cover the topsoil, biocrusts are key drivers for biogeochemical and ecological processes and influencing ecosystem development. Microclimatic conditions, texture, water holding capacity, and chemical soil properties lead to the formation of spatial patterns. Sandy nutrient-poor soils in pine forests in the open-cast lignite mining district in Brandenburg are covered by biocrust, dominated by different functional types and species (e.g. algae, mosses, lichens). The photosynthetic activity of these poikilohydric organisms, strongly depending on moisture, affects biocrust function and their impact on soil C pools and dynamics. Therefore, the evaluation of photosynthesis in relation to the spatial distribution pattern variation is fundamental. For this purpose, we combined different remote sensing techniques, spectral reflectance sensors, and chlorophyll fluorescence imaging to analyze the photosynthetic dynamics in relation to biocrust species composition and wetness. Desiccation of the biocrusts was detected with a miniature moisture sensor and related to their activity. A low-cost consumer grade camera was used to determine NDVI and to map the distribution and heterogeneity of chlorophyll for a comprehensive characterization of spatial photosynthetic activity pattern. Basic as well as maximum fluorescence, the maximum photochemical efficiency, and NDVI decreased during desiccation of the biocrusts, whereby moss and moss/lichen biocrusts showed higher water holding capacities relative to green algae biocrusts. The combination of different sensor technologies is a powerful tool for monitoring long-term biocrust development and their implication for soil C dynamics. Y1 - 2019 UR - https://www.gfoe-conference.de/WEBS/GFOe2019.pages.download/Book_of_Abstracts2019.pdf SP - 199 ER - 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 -