In the frame of the project microbial turnover processes of phosphorous shall be investigated in forest soils and drivers for the corresponding populations as well as their activity pattern shall be described. Furthermore microbial transport and uptake systems for phosphorous should be characterized to understand the competition between plants and microbes for phosphorous in more detail, in relation to the availability of phosphorous and other nutrients. Therefore it is planned to investigate different soil compartments with different nutrient amounts (litter layer - rhizosphere - bulk soil). To reach the described goal molecular metagenomic methods will be used to characterize the structure and function of microbial communities as well as to describe the regulation of selected important pathways. In addition quantitative real time PCR and enzymatic measurements will be used to describe the abundance and activity of the corresponding populations and to describe their relevance for P turnover in the different soil compartments under investigation. With this we hope to reconstruct mainly the microbial phosphorous cycle and give important data to improve the model development of P dynamics in forest soils.
Phosphorus (P) is an essential nutrient for living organisms. Whereas agriculture avoids P-limitation of primary production through continuous application of P fertilizers, forest ecosystems have developed highly efficient strategies to adapt to low P supply. A main hypothesis of the SPP 1685 is that P depletion of soils drives forest ecosystems from P acquiring system (efficient mobilization of P from the mineral phase) to P recycling systems (highly efficient cycling of P). Regarding P fluxes in soils and from soil to streamwater, this leads to the assumption that recycling systems may have developed strategies to minimize P losses. Further, not only the quantity but also the chemistry (P forms) of transported or accumulated P will differ between the ecosystems. In our project, we will therefore experimentally test the relevance of the two contrasting hypothetical nutritional strategies for P transport processes through the soil and into streamwater. As transport processes will occur especially during heavy rainfall events, when preferential flow pathways (PFPs) are connected, we will focus on identifying those subsurface transport paths. The chemical P fractionation in PFPs will be analyzed to draw conclusions on P accumulation and transport mechanism in soils differing in their availability of mineral bound P (SPP core sites). The second approach is an intensive streamwater monitoring to detect P losses from soil to water. The understanding of P transport processes and P fluxes at small catchment scale is fundamental for estimating the P exports of forest soils into streams. With a hydrological model we will simulate soil water fluxes and estimate P export fluxes for the different ecosystems based on these simulations.
In this project, we will investigate the spatial heterogeneity of soil phosphorus (concentration of total P, P speciation) in soils with different P status with modern analytical (synchrotron-based X-ray spectroscopy and spectromicroscopy) and geostatistical methods at different scales (soil aggregates: (sub)micron to mm scale; particular regions of soil profiles (e.g. root channels, surrounding of stones): mm to dm scale; entire soil profiles: dm to m scale; selected patches of the forest stand: m to 5m scale). We expect that our results will provide new insights about spatial heterogeneity patterns of soil P concentration and P speciation in forest soils and their relevance for P availability and P nutritional status of Norway spruce and European beech.
Plant uptake of phosphate (P) in complex forest ecosystems relies to a great extent on microbial mineralization of P from organic and inorganic sources but the relative contributions of the microbial communities to P cycling and allocation in forest soils is not yet very well understood. Within this project we will focus on two interactions that could elucidate key processes of microbial P dynamics in forest sites. We want to clarify the importance of both fungal-fungal and bacterial-fungal interactions for P dynamics in forest soils that are transitioning from P acquiring (efficient mobilization of P from primary and secondary minerals) into P recycling systems (highly efficient cycling of P). We want to reveal furthermore the relative contributions of saprotrophic and ectomycorrhizal fungi to P cycling and allocation. Following a hierarchical approach we want to investigate: (I) the fungal-fungal interaction between saprotrophic and ectomycorrhizal fungi at the plot scale by a systematical exclusion of ectomycorrhizal fungi in the field; (II) elucidate the P dynamics in the mycosphere at the small scale (mm to cm scale) by the use of trenching experiments. (III) investigate the regulation of bacterial as well as fungal P cycling in a microcosm experiment and evaluate the particular microbial uptake, allocation and cycling of P in the mycosphere by the use of several chemical and microbiological approaches. The trenching experiments will be performed on the study sites: Bad Brückenau, Conventwald, Vessertal, Mitterfels and Lüss in close proximity to beech trees (Fagus sylvatica L.). The microcosm experiment will be performed under controlled conditions in the lab.
Steigende Biomasseentzüge aus Wäldern, erhöhtes Waldwachstum durch anhaltend hohe atmosphärische Stickstoffeinträge und direkte und indirekte Auswirkungen des Klimawandels rücken den Kreislauf und die Verfügbarkeit von Phosphor (P) in Waldökosystemen vermehrt in den Fokus wissenschaftlicher Untersuchungen. Den P-Verlusten mit dem Sickerwasser kommt dabei außerdem besondere Bedeutung für die Eutrophierung von Oberflächengewässern zu. Bisher liegen jedoch kaum Erkenntnisse über die Höhe und Prozessdynamik des P-Austrags und die Transportwege von P in Waldböden vor. Eigene Studien zeigten kürzlich, dass signifikante P-Verluste aus Waldböden während starker Niederschlagsereignisse auftreten können. Da der Oberflächenabfluss in Wälder in der Regel vernachlässigbar ist, spielt insbesondere der Transport über preferentielle Fließwege (z.B. Makroporen) eine wichtige Rolle. Welche Prozesse jedoch den P-Transport entlang dieser Fließwege steuern und welche P-Formen überwiegend transportiert werden, ist weitestgehend unbekannt. Ebenso wurde bisher nicht untersucht, ob unterschiedliche Ernährungsstrategien von Waldökosystemen einen Effekt auf die P-Transportmechanismen haben. Eine Grundannahme des SPP 1685 ist, dass recycelnde Systeme, in denen die P- Verfügbarkeit aus der mineralischen Phase gering ist, sich an diese P-Limitierung angepasst haben. Sie können Phosphor hoch effizient recyceln und P-Verluste aus dem System minimieren. Dagegen bestand für akquirierende Systeme, welche überwiegend verfügbares P der mineralischen Phase nutzen, vermutlich nicht die Notwendigkeit angepasste Strategien zu einem effizienten P-Recycling zu entwickeln. Um die Relevanz dieser beiden hypothetischen Ernährungsstrategien auf P-Transportprozesse in Waldböden experimentell zu überprüfen, werden wir daher Böden in Waldökosystemen mit unterschiedlicher P-Verfügbarkeit aus der mineralischen Phase betrachten (SPP-Kernstandorte). Die Ziele unserer Studie sind dabei: 1) die Identifizierung der P-Transportpfade durch den Boden und der am Transport beteiligten P-Formen; 2) die modell-basierte Abschätzung der P-Verluste aus den betrachteten Systemen. Die preferentiellen Fließwege von infiltrierendem Wasser sollen mit Hilfe von Farbtracer-Experimenten visualisiert werden. Durch die anschließende chemische Analyse der P-Fraktionen in den preferentiellen Fließwegen sollen Rückschlüsse auf P-Transportmechanismen in Waldböden gezogen werden. Zur Abschätzung der P-Verluste aus dem System werden basierend auf den identifizierten Transportmechanismen und beobachteten Fließwegen numerische Modelle parametrisiert, welche die Komponenten des Wasserhaushaltes simulieren. Durch diesen kombinierten Ansatz können erstmals die Transportmechanismen und Austragsraten von Phosphor aus Waldökosystemen in Abhängigkeit ihrer Ernährungsstrategie (P-Verfügbarkeit aus der mineralischen Phase) vergleichend betrachtet werden.
Überwachung der Umweltradioaktivität aus künstlichen und natürlichen Quellen: Luft, Gewässer, Niederschläge, Erdboden, Gras, Lebensmittel, Strahlendosen, in-situ-Messungen Überwachung von Kernanlagen, Betrieben und Spitälern die radioaktive Stoffe verwenden Erfassung der natürlichen Radioaktivität etc. Koordination des nationalen Überwachungsprogrammes Sammlung, Auswertung und Veröffentlichung der Daten sowie Ermittlung der Strahlendosen der Bevölkerung aus künstlichen und natürlichen Strahlenquellen Weiterentwicklung der Überwachungs- und Messverfahren die Ergebnisse werden jährlich vom Amt (als Print) und auf dem Internet veröffentlicht.
The Clean Development Mechanism (CDM) suffers from a price level for certificates that went down to almost zero in a period less than a year. Additionally, no short-term price recovery is expected which could incentivise new projects. A risk is that market participants leave the market and the valuable CDM knowledge base on GHG mitigation and quantification will be lost. The CDM Market Support Study analyses the actual price vulnerability of projects and identifies various financing and project type opportunities for project developers and for (institutional public) investors who intent to support the CDM project continuation and the further development of the CDM framework. The study also shows how the current regulatory framework of the CDM can be maintained by transferring it to future mechanisms. This could be a chance to develop the CDM from a pure market-based instrument towards an integrated part within future market-based and also policy-based instruments. The CDM can provide useful components to currently discussed or tested instruments such as the NMM (New Market Mechanism), the FVA (Framework for Varios Approaches), NAMAs (Nationally Appropriate Mitigation Actions) or results-based financing approaches. The study was financed by the German KfW-managed PoA Support Centre . The aim of the PoA-Support-Centre Germany is to support the development of Programmes of Activities (PoAs) under CDM and JI (Joint Implementation) worldwide.
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