Das Projekt "Effects of water content, input of roots and dissolved organic matter and spatial inaccessibility on C turnover & determination of the spatial variability of subsoil properties" wird/wurde gefördert durch: Deutsche Forschungsgemeinschaft. Es wird/wurde ausgeführt durch: Universität Kassel, Lehr- und Forschungsgebiet Umwelt- und Lebensmittelwissenschaften, Fachgebiet Umweltchemie.It is well established that reduced supply of fresh organic matter, interactions of organic matter with mineral phases and spatial inaccessibility affect C stocks in subsoils. However, quantitative information required for a better understanding of the contribution of each of the different processes to C sequestration in subsoils and for improvements of subsoil C models is scarce. The same is true for the main controlling factors of the decomposition rates of soil organic matter in subsoils. Moreover, information on spatial variabilities of different properties in the subsoil is rare. The few studies available which couple near and middle infrared spectroscopy (NIRS/MIRS) with geostatistical approaches indicate a potential for the creation of spatial maps which may show hot spots with increased biological activities in the soil profile and their effects on the distribution of C contents. Objectives are (i) to determine the mean residence time of subsoil C in different fractions by applying fractionation procedures in combination with 14C measurements; (ii) to study the effects of water content, input of 13C-labelled roots and dissolved organic matter and spatial inaccessibility on C turnover in an automatic microcosm system; (iii) to determine general soil properties and soil biological and chemical characteristics using NIRS and MIRS, and (iv) to extrapolate the measured and estimated soil properties to the vertical profiles by using different spatial interpolation techniques. For the NIRS/MIRS applications, sample pretreatment (air-dried vs. freeze-dried samples) and calibration procedures (a modified partial least square (MPLS) approach vs. a genetic algorithm coupled with MPLS or PLS) will be optimized. We hypothesize that the combined application of chemical fractionation in combination with 14C measurements and the results of the incubation experiments will give the pool sizes of passive, intermediate, labile and very labile C and N and the mean residence times of labile and very labile C and N. These results will make it possible to initialize the new quantitative model to be developed by subproject PC. Additionally, we hypothesize that the sample pretreatment 'freeze-drying' will be more useful for the estimation of soil biological characteristics than air-drying. The GA-MPLS and GA-PLS approaches are expected to give better estimates of the soil characteristics than the MPLS and PLS approaches. The spatial maps for the different subsoil characteristics in combination with the spatial maps of temperature and water contents will presumably enable us to explain the spatial heterogeneity of C contents.
Das Projekt "Quantification of the influence of current use fungicides and climate change on allochthonous Organic MATer decomposition in streams (QUANTOMAT)" wird/wurde gefördert durch: Deutsche Forschungsgemeinschaft. Es wird/wurde ausgeführt durch: Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, Institut für Umweltwissenschaften.The decomposition of terrestrial organic material such as leaf litter represents a fundamental ecosystem function in streams that delivers energy for local and downstream food webs. Although agriculture dominates most regions in Europe and fungicides are applied widely, effects of currently used fungicides on the aquatic decomposer community and consequently the leaf decomposition rate are largely unknown. Also potential compensation of such hypothesised adverse effects due to nutrients or higher average water temperatures associated with climate change are not considered. Moreover, climate change is predicted to alter the community of aquatic decomposers and an open question is, whether this alteration impacts the leaf decomposition rate. The current projects follows a tripartite design to answer these research questions. Firstly, a field study in a vine growing region where fungicides are applied in large amounts will be conducted to whether there is a dose-response relationship between the exposure to fungicides and the leaf decomposition rate. Secondly, experiments in artificial streams with field communities will be carried out to assess potential compensatory mechanisms of nutrients and temperature for effects of fungicides. Thirdly, field experiments with communities exhibiting a gradient of taxa sensitive to climate change will be used to investigate potential climate-related effects on the leaf decomposition rate.
Der Kartendienst (WMS Gruppe) stellt Geodaten aus dem Bereich Mobilität im Saarland dar.:Raster 1000m symbolisiert nach dem Attribut "Anteil attraktiver Wege ÖV" im Zeitraum zwischen 3 und 6 Uhr.
Der Kartendienst (WMS Gruppe) stellt Geodaten aus dem Bereich Mobilität im Saarland dar.:Raster 1000m symbolisiert nach dem Attribut "Anteil attraktiver Wege ÖV" im Zeitraum zwischen 21 und 24 Uhr.
Der Kartendienst (WMS Gruppe) stellt Geodaten aus dem Bereich Mobilität im Saarland dar.:Raster 1000m symbolisiert nach dem Attribut "Anteil attraktiver Wege ÖV" im Zeitraum zwischen 0 und 3 Uhr.
Der Kartendienst (WMS Gruppe) stellt Geodaten aus dem Bereich Mobilität im Saarland dar.:Raster 1000m symbolisiert nach dem Attribut "Anteil attraktiver Wege ÖV" im Zeitraum zwischen 15 und 18 Uhr.
Der Kartendienst (WMS Gruppe) stellt Geodaten aus dem Bereich Mobilität im Saarland dar.:Raster 1000m symbolisiert nach dem Attribut "Anteil attraktiver Wege ÖV" im Zeitraum zwischen 18 und 21 Uhr.
Der Kartendienst (WMS Gruppe) stellt Geodaten aus dem Bereich Mobilität im Saarland dar.:Raster 1000m symbolisiert nach dem Attribut "Anteil attraktiver Wege ÖV" im Zeitraum zwischen 9 und 12 Uhr.
Der Kartendienst (WMS Gruppe) stellt Geodaten aus dem Bereich Mobilität im Saarland dar.:Raster 1000m symbolisiert nach dem Attribut "Anteil attraktiver Wege ÖV" im Zeitraum zwischen 6 und 9 Uhr.
Der Kartendienst (WMS Gruppe) stellt Geodaten aus dem Bereich Mobilität im Saarland dar.:Raster 1000m symbolisiert nach dem Attribut "Anteil attraktiver Wege ÖV" im Zeitraum zwischen 12 und 15 Uhr.
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