Organic matter (OM) composition and dynamic in subsoils is thought to be significantly different from those in surface soils. This has been suggested by increasing apparent 14C ages of bulk soil OM with depth suggesting that the amount of fresh, more easily degradable components is declining. Compositional changes have been inferred from declining ä13C values and C/N ratios indicative for stronger OM transformation. Beside these bulk OM data more specific results on OM composition and preservation mechanisms are very limited but modelling studies and results from incubation experiments suggest the presence and mineralization of younger, 'reactive carbon pool in subsoils. Less refractory OM components may be protected against degradation by interaction with soil mineral particles and within aggregates as suggested by the very limited number of more specific OM analysis e.g., identification of organic compound in soil fractions. The objective of this project is to characterize the composition, transformation, stabilization and bioavailability of OM in subsurface horizons on the molecular level: 1) major sources and compositional changes with depth will be identified by analysis of different lipid compound classes in surface and subsoil horizons, 2) the origin and stabilization of 'reactive OM will be revealed by lipid distributions and 14C values of soil fractions and of selected plant-specific lipids, and 3) organic substrates metabolized by microbial communities in subsoils are identified by distributional and 14C analysis of microbial membrane lipids. Besides detailed analyses of three soil profiles at the subsoil observatory site (Grinderwald), information on regional variability will be gained from analyses of soil profiles at sites with different parent material.
Soil microorganisms can mobilize and immobilize phosphorus (P), and therefore strongly affect the availability of P to plants. In this project we hypothesize that the ratio of labile P to microbial P increases during the transition from acquiring to recycling ecosystems. Microbial and plant P uptake will be studied with 33P that will be quantified in microbial and plant biomass as well as in lipids. To what extent microorganisms immobilize and mobilize P during decomposition of soil organic matter will be explored with a 14C/33P labeled monoester. Seasonal dynamics of actual and potential P mineralization (33P dilution and phosphatase activity), and microbial P immobilization will be studied with soils of the transition from acquiring to recycling ecosystems. The contribution of litter-derived P will be explored in a litter exclusion experiment in the field. Spatial patterns of microbial and plant P mineralization in the rhizosphere will be explored by analyses of areas of high acid and alkaline (=microbial-derived) phosphatase activity by soil zymography, and their relations with areas of high rhizodeposition (14C imaging). In conclusion, we will analyse mechanisms of actual and potential microbial P mineralization and immobilization, localization, and consequences for P uptake by plants.
Atmospheric CO2 concentrations present a repetitive pattern of gradual decline and rapid increase during the last climate cycles, closely related to temperature and sea level change. During the Last Glacial Maximum (LGM; 23-19 kyr BP), when sea level was ca. 120 m below present, the ocean must have stored additionally about 750 Gt carbon. There is consensus that the Southern Ocean represents a key area governing past and present CO2 change. The latter is not only of high scientific but also of socio-economic and political concern since the Southern Ocean provides the potential for an efficient sink of anthropogenic carbon. However, the sensitivity of this carbon sink to climate-change induced reorganizations in wind patterns, ocean circulation, stratification, sea ice extent and biological production remains under debate. Models were not yet able to reproduce the necessary mechanisms involved, potentially due to a lack of the dynamic representation/resolution of atmospheric and oceanic circulation as well as missing carbon cycling. Data on past Southern Ocean hydrography and productivity are mainly from the Atlantic sector, thus do not adequately document conditions in the Pacific sector. This sector is not only the largest part of the Southern Ocean, but it also represents the main drainage area of the marine-based West Antarctic Ice Sheet (WAIS). In the proposed study we aim to generate paleo-data sets with a newly established proxy method from sediment core transects across the Pacific Southern Ocean. This will enhance the baselines for the understanding and modeling of the Southern Ocean's role in carbon cyling, i.e. ocean/atmosphere CO2 exchange and carbon sequestration. It will also allow insight into the response of the WAIS to past warmer than present conditions. Paired isotope measurements (oxygen, silicon) will be made on purified diatoms and radiolarians to describe glacial/interglacial contrasts in physical and nutrient properties at surface and subsurface water depth. This will be used to test (i) the impact of yet unconsidered dust-borne micronutrient deposition on the glacial South Pacific on shifts of primary productivity, Si-uptake rates and carbon export, (ii) the 'silicic-acid leakage' hypothesis (SALH) and (iii) the formation and extent of surface water stratification. Diatom and radiolarian oxygen isotopes will provide information on the timing of surface ocean salinity anomalies resulting from WAIS melt water. Climate model simulations using a complex coupled atmosphere ocean general circulation model (AOGCM) in combination with a sophisticated ocean biogeochemical model including Si-isotopes will be used for comparison with the paleo records. The analysis will cover spatial as well as temporal variability patterns of Southern Ocean hydrography, nutrient cycling and air-sea CO2-exchange. With the help of the climate model we aim to better separate and statistically analyse the individual impacts of ocean circulation and bio
Up to recent years, the study of trends and variability of the salinity (and freshwater) distributions was hampered by the lack of temporal and spatial resolution of the available observations (Wang DFG form 54.011 - 1/12 page 3 of 6 et al., 2010). With the onset of the Argo programme, the number of observed salinity profiles have significantly increased. The many Argo profiles distributed evenly over the year provide not only the means to calculate seasonally averaged salinity (and freshwater) distributions, but they can also be used to calculate regional Gravest Empirical Modes (GEMs) parameterized by pressure and dynamic height. Dynamic height is measured by altimetry and high quality altimeter data are available since 1992. GEMs will be used to construct from altimetry high resolution (in time and space) salinity, temperature and density fields. The objectives of the proposal are to - combine Argo/CTD profiles and altimetry to calculate temporal and spatial high resolution salinity fields in the mixed layer and in the upper 1500-2000m for the time period 1992 - 2013 for the subpolar and the subtropical Atlantic. - Construct regional freshwater budgets for the mixed layer and the upper 1500-2000m and estimate the contributions of the main processes to the observed change - Follow salinity anomalies from their origin along their circulation pathways, and study involved mechanisms (for instance role of eddies, mean circulation) for shallow, intermediate and deep water masses - Investigate changes in the formation of North Atlantic mode waters in the subpolar and subtropical gyre
Peroxyradikale sind kurzlebige Spezies, die an den meisten Oxidationsprozessen in der Atmosphäre beteiligt sind, die zur Bildung von langlebigeren und chemisch oder toxikologisch wichtigen Schadstoffen wie Ozon führen. Insbesondere in Gebieten, die von komplexen Emissionsquellen betroffen sind, sind Peroxyradikal-Messmethoden mit ausreichender Genauigkeit, Reproduzierbarkeit und Empfindlichkeit erforderlich, um die chemische Umwandlung der städtischen Umweltverschmutzung zu verstehen. In dieser Hinsicht ermöglichen Vergleiche von state-of-the-art Sensoren in chemischen Reaktorkammern deren Charakterisierung unter kontrollierten Bedingungen und verbessern das Vertrauen in die Messung von Peroxyradikalen.SPRUCE strebt ein besseres Verständnis der Rolle der Peroxyradikale bei atmosphärischen chemischen Umwandlungen an, die aus der Wechselwirkung zwischen urbanen anthropogenen und ländlichen biogenen Emissionen resultieren. Im Rahmen der vorgeschlagenen Arbeit wird das vorhandene PeRCEAS-Instrument (Peroxy Radical Chemical Enhancement and Absorption Spectrometer) an der Messkampagne des internationalen Projekts ACROSS (Atmospheric ChemistRy Of the Suburban Forest) zur Untersuchung des Schadstoffausflusses von Paris über ein Waldgebiet, und in der internationalen Vergleichsstudie ROxCOMP22 für wissenschaftliche Instrumente, die atmosphärische Peroxyradikale teilnehmen. Diese beiden Messkampagnen befassen sich mit zwei Hauptaspekten von SPRUCE. Sie bieten eine einzigartige Gelegenheit für a) die Messung von Peroxyradikalen in der spezifischen Umgebung von Interesse und in Verbindung mit einer umfangreichen Reihe von Beobachtungen, die für die Interpretation der Radikalchemie von wesentlicher Bedeutung sind, und b) die Bewertung der Datenqualität und Leistungsfähigkeit von PeRCEAS, insbesondere die Überprüfung der Sensitivität und Effizienz für die Speziation der Radikale unter kontrollierten Bedingungen.Ein Schwerpunkt der Studie wird auf der Untersuchung von Oxidationsreaktionen und Ozonausbeuten in Luftmassen mit unterschiedlicher anthropogener/biogener Signatur in Abhängigkeit von der Menge und Zusammensetzung von Peroxyradikalen liegen. Numerische Berechnungen und Modelle werden durch die Beobachtungen von Vorläuferspezies eingeschränkt, um die Budgets von Peroxyradikalen abzuschätzen. Der Vergleich mit den PeRCEAS-Messungen wird verwendet, um das Verständnis der Oxidationsmechanismen in urbanen Plumes gemischt mit biogenen Emissionen zu testen. Es wird erwartet, dass die Analyse des resultierenden Datensatzes das aktuelle Wissen über die chemische Transformation von Megacity-Emissionen während des atmosphärischen Transports ergänzt.
Cydia pomonella granulovirus (CpGV, Baculoviridae) is one of the most important agents for the control of codling moth (CM, Cydia pomonella, L.) in both biological and integrated pest management. The rapid emergence of resistance against CpGV-M, which was observed in about 40 European CM field populations from 2003 on, could be traced back to a single, dominant, sex-linked gene. Since then, resistance management has been based on mixtures of new CpGV isolates (CpGV-I12, -S), which are able to overcome this resistance. Recently, resistance even to these novel isolates was observed in CM field populations. This resistance does not follow the described dominant, sex-linked inheritance trait. At the same time, another isolate CpGV-V15 was identified showing high virulence against these resistant populations. To elucidate this novel resistance mechanism and to identify the resistance gene(s) involved, we propose a comprehensive analysis of this resistance on the cellular and genomic level of codling moth. Because of the lack of previous knowledge of the molecular mechanisms of virus resistance in insects, several different and complementary approaches will be pursued. This study will not only give an in-depth insight into the genetic possibilities for development of baculovirus resistance in CM field populations and how the virus overcomes it, but can also serve as an important model for other baculovirus-host interaction systems.
Cherry leaf roll virus (CLRV) is a plant pathogen of economic and ecologic importance. It is globally distributed in a wide range of forest, fruit, and ornamental trees and shrubs. In several areas of cherry and walnut production CLRV causes severe losses in yield and quality. With current reference to the rapid dissemination and strong symptom expression in Finnish birches and the Germany-wide distribution of CLRV in birches and elderberry, we continuously investigate and gradually reveal CLRV transmission pathways as by pollen, seeds or water. However, modes and interactions responsible for the wide intergeneric host transmission as well as for the exceptional CLRV epidemic in Fennoscandia still remain unknown. In this project systematic studies shall investigate biological vectors as a causal agent to finally derive control mechanisms and strategies to avoid new epidemics in different hosts and geographic regions. Detailed monitoring of the invertebrate fauna of birch stands/forests and elderberry plantations in Germany and Finland shall reveal potential vectors to subsequently study them in detail by approved virus detection methods and transmission experiments. Molecular analyses of the CLRV coat protein shall prove its role as a viral determinant for a virus/vector interaction. Consequently, this project essentially will contribute important answers on the CLRV epidemiology, and this will be a key element within the first network of research on plant viral pathogens in forest trees.
Changes in agroecosystem management (e.g. landscape diversity, management intensity) affect the natural control of pests. The effects of agricultural change on this ecosystem service, however, are not universal and the mechanisms affecting it remain to be understood. As biological control is effectively the product of networks of interactions between pests and their natural enemies, food web analysis provides a versatile tool to address this gap of knowledge. The proposed project will utilize a molecular food web approach and examine, for the first time, how changes in plant fertilisation and landscape complexity affect quantitative aphid-parasitoid-hyperparasitoid food webs on a species-specific level to unravel how changes in food web interactions affect parasitoid aphid control. Based on the fieldderived data, cage experiments will be conducted to assess how parasitoid diversity and identity affect parasitoid interactions and pest control, complementing the field results. The work proposed here will take research on parasitoid aphid control one step further, as it will provide a clearer understanding of how plant fertilization affects whole aphid-parasitoid food webs in both simple and complex landscapes, allowing for further improvements in natural pest control.
Deviant behaviour on various levels of the food supply chain may cause food risks. It entails irregular technological procedures which cause (increased probabilities of) adverse outcomes for buyers and consumers. Besides technological hazards and hitherto unknown health threats, moral hazard and malpractice in food businesses represent an additional source of risk which can be termed 'behavioural food risk'. From a regulatory perspective, adverse outcomes associated with deviance represent negative externalities that are caused by the breaking of rules designed to prevent them. From a rational choice perspective, the probability of malpractice increases with the benefits for its authors. It decreases with the probability of detection and resulting losses. It also decreases with bonds to social norms that protect producers from yielding to economic temptations. The design of mechanisms that reduce behavioural risks and prevent malpractice requires an understanding of why food businesses obey or do not obey the rules. This project aims to contribute to a better understanding of malpractice on the restaurant/retail level through comparative case studies and statistical analyses of food inspection and survey data. Accounting for the complexity of economic behaviour, we will not only look at economic incentives but consider all relevant behavioural determinants, including social context factors.
The aim of this project is to develop a methodology to quantify the magnitudes and frequencies of individual surface change processes of a rock glacier over several years. We do this by analyzing three dimensional (3D) surface change based on high-resolution, high-frequency and multisource LiDAR data. The derived information will enable us to develop methods to automatically characterize and disaggregate multiple processes and mechanisms that contribute to surface change signals derived from less frequent monitoring (e.g. yearly). Such methods can enhance our general understanding of the spatial and temporal variability of rock glacier deformation and the interaction of rock glaciers with connected environmental systems.
| Organisation | Count |
|---|---|
| Bund | 258 |
| Europa | 2 |
| Wissenschaft | 124 |
| Zivilgesellschaft | 1 |
| Type | Count |
|---|---|
| Förderprogramm | 258 |
| License | Count |
|---|---|
| Offen | 258 |
| Language | Count |
|---|---|
| Deutsch | 50 |
| Englisch | 248 |
| Resource type | Count |
|---|---|
| Keine | 203 |
| Webseite | 55 |
| Topic | Count |
|---|---|
| Boden | 213 |
| Lebewesen und Lebensräume | 249 |
| Luft | 198 |
| Mensch und Umwelt | 258 |
| Wasser | 195 |
| Weitere | 258 |