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WiSSCy: Impact of Wind, Rain, and Surface Slicks on Air-Sea CO2 Transfer Velocity - Tank Experiments

Das Projekt "WiSSCy: Impact of Wind, Rain, and Surface Slicks on Air-Sea CO2 Transfer Velocity - Tank Experiments" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Zentrum für Meeres- und Klimaforschung, Institut für Meereskunde (IfM) durchgeführt. The goal is to improve the understanding of the parameterization of air-sea gas exchange with emphasis on CO2. This is being done using the linear wind-wave tank facility of the University of Hamburg. Using this facility, gas exchange coefficients are inferred by measuring gas transfer under a wide variety of parameters such as wind, mechanically generated waves, rain, and surface films. Our emphasis is on the physical processes involved in the air-sea gas exchange and its quantitative measurement. Experiments are conducted with freshwater and with salt water to test the influence of salinity on the gas exchange parameters. All experiments are being performed for evasion and invasion to investigate if rain-induced gas transfer is symmetrical or asymmetrical. While these experiments do not address in great detail the small-scale processes that are involved in the transfer, they allow to determine parameterizations of the gas exchange as a function of parameters of the atmospheric boundary layers as they are needed in climate models and for the analysis of satellite data.

DOAS Messungen von der NASA Global Hawk während des NASA-ATTREX Projektes

Das Projekt "DOAS Messungen von der NASA Global Hawk während des NASA-ATTREX Projektes" wird vom Umweltbundesamt gefördert und von Universität Heidelberg, Institut für Umweltphysik durchgeführt. The present project addresses differential optical absorption spectrometry (DOAS) measurements in scanning limb geometry from aboard the unmanned high-flying aircraft NASA Global Hawk (GH). The DOAS measurements are made within the NASA sponsored ATTREX (Airborne Tropical TRopopause EXperiment) project, by a 3 channel (UV/vis/nearer) optical spectrometer financed by NASA, but mostly built in Heidelberg. In fall 2011 and winter 2012/13 successful flights were already successfully performed and the DOAS instrument peformed. Within ATTREX three field campaigns are planned to take place in the Western Pacific (from EAFB, GUAM, and Darwin) in the years 2013 to 2014 (Jan./Feb. 2013, Jan./Feb. 2014 and June/July 2014). The field campaigns comprise about 50 GH sorties with 600 flight hours spent air-borne. Major scientific foci of the NASA-ATTREX project are the photochemistry, the microphysics of aerosols and cloud particles, and air mass transport into and within the tropical tropopause layer (TTL). The DOAS measurements aim to measure the vertical profiles in the TTL of ozone relevant species such as O3, HONO, NO2, C2H2O2, CH2O, O4, BrO, OClO, IO, and OIO, and of some microphysical properties aerosols and clouds, i.e., the particle phase function, Mie scattering extinction coefficient, the ice water path (IWP) and probably the ice water content (IWC). Together with complementary observations made by other instruments aboard the GH, the DOAS measurements may serve to particularily provide new insights into (a) the photochemistry of halogen oxides (OClO, BrO and IO) in the TTL, in particular on the contribution of so called halogenated Very Short Lived Species (VSLS) to the budgets of stratospheric halogens, (b) the impact of lightning produced NOx and HOx (NO2, and HONO) and other of radicals (c.f. CH2O, BrO, IO) to the oxidation capacity of air in the outflow region of deep convection, and (c) to the abundance and micro-physical properties of frozen aerosols and cloud particles in the upper tropical troposphere and TTL.

D 1.2: Reducing alternation and production of off-season fruits in Lychee, Longan and Mango

Das Projekt "D 1.2: Reducing alternation and production of off-season fruits in Lychee, Longan and Mango" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Kulturpflanzenwissenschaften (340), Fachgebiet Düngung und Bodenstoffhaushalt (340i) durchgeführt. The aim and vision of sub-project D1.2 was and is to encourage hillside farmers to plant erosion resistant fruit trees instead of erosion susceptible annual plants. For that reason, experiments to overcome the irregular bearing behaviour of the three most common fruit tree species in Northern Thailand (Litchi, Longan and Mango) from the first SFB period will be continued in order to make their planting more attractive to the farmers. Considerable progress has been made in D1 during the past 3 years to induce flowers and fruit in Longan trees by the application of KClO3 . With this technique, it was not only possible to induce year around flowers and fruit (off season fruit) but also to overcome the generally rather irregular fruiting behaviour of these trees. A similar technique is now being developed for Mango by using an inhibitor of the bio-synthesis of the plant hormone gibberellin. Only Litchi still resist this kind of manipulation by an 'off season technique' (OST). Great effort will therefore be devoted establishing a similar system for this species as well. Reliably, this can only be done by gaining a much better knowledge of the - most certainly hormonal - regulatory system that governs flower induction in trees. Investigations into the hormonal changes taking place during natural and induced flower induction is, therefore, one of the central objectives in this sub-project, with the goal to better understand the process of flower induction. Until now most of the progress in this area is entirely empirical in nature and a more specific manipulation therefore difficult. While the ability to produce off season fruit all year around and under various weather conditions has brought about a great number of new possibilities, new challenges will still be faced with regard to these methods. These circumstances will affect the whole production chain from the orchard to the market and consumer. In order to better investigate and understand these new situations, a large model experiment with Mango will be set up and problems like tree pruning, water and nutrient demand, phytopathological problems, demand on work force, fruit processing and drying etc. will be investigated by the interdisciplinary co-operation of 8 sub-projects within the SFB. The results obtained during these investigations will be shared with hillside farmers enabling them to take advantage of these new possibilities, which will provide for more reliable yields and allow them to market fruit year around. In general, these new opportunities should encourage farmers to plant more trees and thus reduce erosion. However, to make this system not only reliable and economic but also ecologically and socially beneficial to the society all potential benefits as well as risks have to be evaluated carefully from all different aspects.

SP 2.3 Decision support systems for weed management in North China Plain production systems

Das Projekt "SP 2.3 Decision support systems for weed management in North China Plain production systems" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Tropische Agrarwissenschaften (Hans-Ruthenberg-Institut) (490), Fachgebiet Agrarökologie der Tropen und Substropen (490f) durchgeführt. Wide applications in Europe show that weed management strategies can be considerably improved when computerized expert systems, decision models and population-dynamic models are applied. If these management systems are transferred and adapted to the specific production systems of the North China Plain, herbicide use can be significantly reduced and the evolution of persistent weed populations in the major arable crops can be avoided. The main objective of this subproject will be to create efficacy-based models analyzing herbicide performance in major crops and to create population-based models for herbicide use analyzing the yield losses caused by weed competition. For these models it is necessary to determine the sensitivity of major weed species to herbicides and to explore the potential of reduced dose rates for herbicide use. Furthermore it is necessary to investigate weed management practices combining preventive (timing of seeding, crop rotation and tillage) and direct methods (chemical and physical methods) of weed control. For population dynamic models it is necessary to determine long-term economic weed threshold estimating the changes in the soil seed bank. Finally both models will be combined in a decision support system for weed control in North China Plain Production Systems. The applicability of this decision support system will be tested in field experiments.

C 1.2: Analysis and manipulation of the agro-biocoenosis for sustainable management of litchi growing systems at hillsides of Northern Thailand

Das Projekt "C 1.2: Analysis and manipulation of the agro-biocoenosis for sustainable management of litchi growing systems at hillsides of Northern Thailand" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Pflanzenproduktion und Agrarökologie in den Tropen und Subtropen durchgeführt. In the hillsides of northern Thailand, the importance of fruit trees (mainly litchi) is increasing. However, fruit production is limited by a number of biotic and abiotic factors. Frequent applications of herbicides and insecticides result in a grass-dominated herbicide flora of low diversity. Further consequences are low numbers of beneficials, soil erosion and the decline of soil fertility. The aim of the proposed project is the development of a litchi production system with reduced insecticide and herbicide input, which allows both sustainable and profitable land use. This will be achieved by (a) the development of management strategies for preventive measures in pest population control and (b) the establishment of a smother vegetation which leads to an increased diversity of the system, enhancement of beneficials, improved soil conservation and fertility, and which has an additional-use potential (e.g., forage). The experimental approach for studying the effects of management measures (handling of the attendant vegetation and insecticide application in four different treatments) on plant species diversity and the beneficial fauna will be continued from phase 1 in an extended manner. In addition, the long-term monitoring of seasonal changes in abundance of the six major litchi pests, identified in the first phase, will be continued. The migration patterns of these species will also be studied since some of them migrate between the litchi plantations and the surrounding habitats. The parasitoids and predators of these pests will be identified and their abundances recorded. Participatory activities will continue in cooperation with subproject A1.2. They include regular meetings with individual farmers and group interviews for information exchange about pest problems and farmers strategies to cope with these problems. In the first phase, four promising cover legume species with potential for soil enhancement and livestock feeding have been identified. In order to increase biodiversity in fruit orchards, the effects of different mixtures of these species will be studied. At Mae Sa Mai, experiments will show if and how such mixtures, by complementary and compensatory effects, contribute to increased productivity and quality of the understorey vegetation. In addition, changes of soil chemical, physical and biological properties will be monitored. Soil scientist expert advice as well as related data flow is ensured by close cooperation with subprojects B1.2, B2.2 and B3.1. Participatory Monitoring and Evaluation (PM&E) will be carried out jointly with A1.2. In the view of the greater role of livestock in the region of the SFB's second research site (Phang Ma Pha), a parallel replication of the legume mixture research is intended for that site in the form of a complementary NRCT project, also including the pest component of the project.

Non-exchangeable NH4-N in the subsoil:Significance for the N nutrition of plants (NitroNex)

Das Projekt "Non-exchangeable NH4-N in the subsoil:Significance for the N nutrition of plants (NitroNex)" wird vom Umweltbundesamt gefördert und von Universität Bonn, Institut für Nutzpflanzenwissenschaften und Ressourcenschutz - Pflanzenernährung (Prof. Werner) durchgeführt. The project is dealing with the contribution of non-exchangeable NH4-N in the subsoil for the N nutrition of plants. It is divided into two main parts: In part 1 the content of nonexchangeable NH4-N in the subsoil of the Central field experiment (CeFiT) under different crops and influencing factors will be investigated. Special consideration will be given to the drilosphere, where easily mineralizable organic material is translocated into deeper soil layers and NH4+-ions, formed after mineralization may be specifically bound in interlayers of 2:1 clay minerals in the vicinity of biopores. Furthermore attention will be given to the reduction of NO3-, translocated into the subsoil, to NH4+ as a source for NH4+-fixation. In part 2 the amounts of non-exchangeable NH4-N released from subsoils throughout the growing season will be quantified. Special attention will be given to the influence of the root system on the mobilization of NH4+-ions from the interlayers of clay minerals. Partially interlayers of clay minerals will be labelled with 15NH4+. Under field conditions, in the Central microcosm experiment (CeMiX) as well as in model experiments with special containers, that allow to take soil samples from defined distances from the root system, depletion curves of nonexchangeable NH4-N will be created.

The iron-snow regime in Fe-FeS cores: a numerical and experimental approach

Das Projekt "The iron-snow regime in Fe-FeS cores: a numerical and experimental approach" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum Dresden-Roßendorf, Institut für Fluiddynamik durchgeführt. In the Earth, the dynamo action is strongly linked to core freezing. There is a solid inner core, the growth of which provides a buoyancy flux that drives the dynamo. The buoyancy in this case derives from a difference in composition between the solid inner core and the fluid outer core. In planetary bodies smaller than the Earth, however, this core differentiation process may differ - Fe may precipitate at the core-mantle boundary (CMB) rather than in the center and may fall as iron snow and initially remelt with greater depth. A chemical stable sedimentation zone develops that comprises with time the entire core - at that time a solid inner core starts to grow. The dynamics of this system is not well understood and also whether it can generate a magnetic field or not. The Jovian moon Ganymede, which shows a present-day magnetic dipole field, is a candidate for which such a scenario has been suggested. We plan to study this Fe-snow regime with both a numerical and experimental approach. In the numerical study, we use a 2D/3D thermo-chemical convection model that considers crystallization and sinking of iron crystals together with the dynamics of the liquid core phase (for the 3D case the influence of the rotation of the Fe snow process is further studied).The numerical calculations will be complemented by two series of experiments: (1) investigations in metal alloys by means of X-ray radioscopy, and (2) measurements in transparent analogues by optical techniques. The experiments will examine typical features of the iron snow regime. On the one hand they will serve as a tool to validate the numerical approach and on the other hand they will yield important insight into sub-processes of the iron snow regime, which cannot be accessed within the numerical approach due to their complexity.

Pasture rehabilitation on, and management of degraded areas in the Andes of South Ecuador

Das Projekt "Pasture rehabilitation on, and management of degraded areas in the Andes of South Ecuador" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Fachgruppe Biologie, Bayreuther Zentrum für Ökologie und Umweltforschung (BayCEER), Lehrstuhl für Pflanzenphysiologie durchgeführt. Project abstract: This knowledge transfer project will be centered in the San Francisco valley in the South Ecuadorian Andes. However, the problem of abandoning pastures because of heavy infestation by weeds, in particular by bracken fern (Pteridium spec.), is a general issue in the tropical Andes. Pastures which have been abandoned for that reason amount meanwhile to 11Prozent of the area of the San Francisco valley. Infestation by bracken fern and shrubs is a consequence of the traditional use of fire for clearing of the natural forest and pasture management. Growth of both, bracken and woody weeds, is fostered by recurrent burning. In a 2-phase experiment on a heavily bracken-infested slope at c. 2000 m altitude, substantial control of the weed and subsequent pasture rehabilitation could be achieved. In the planned project, this procedure shall be scaled-up to farm level and the altitudinal range of repasturisation shall be extended from 1000 m to 2400 m altitude. To that end local farmers will put respective parts of their land to the projects disposal and public authorities will provide man-power. There are several challenges to be met: (i) Long-term bracken infestation has depleted the soils from nutrients, in particular P and N. Therefore targeted fertilization is needed for profitable grass productivity. (ii) Since bracken can never be completely eradicated, its regrowth must be suppressed by trampling, i.e. frequent grazing. A sustainable grazing management has to be developed which corresponds to soil fertility. (iii) The dominating pasture grass is the C4-type grass Setaria sphacelata. It is growing well in a warm climate but its competitive strength in the harsher climate above 2000 m is low. Bracken as a C3-type plant is less dependent on the temperature. To this adds that it occurs in 2 species in the area, one of which is an upland type. Thus the climate gradient over the elevational transect will influence the competitive strength of both competitors. Therefore the suitability of the traditional monoculture of this grass species for pasture rehabilitation shall be tested in the context of a comprehensive pasture management experiment which the farmers will be involved. (iv) A special problem is the high oxalate concentration in the growing parts of the Setaria leaves which can cause calcaemia in cattle. In a pot experiment which will be run in collaboration with a research team of the UTPL, feeding quality and toxicity of a monotonous diet of Setaria will be tested. Beside the experimental areas, demonstration sites will be installed where regular training workshops will be organized to encourage the farmers to apply the developed rehabilitation and management strategy to their own farms.

Shift in the syncronisation of leaf decay processes in fragmented streams

Das Projekt "Shift in the syncronisation of leaf decay processes in fragmented streams" wird vom Umweltbundesamt gefördert und von Technische Universität Cottbus, Institut für Boden, Wasser, Luft, Lehrstuhl für Gewässerschutz, Forschungsstelle Bad Saarow durchgeführt. Climate change will increase summer droughts and cause both, premature leaf fall and temporary fragmentation of streams into a series of pools. This match of low flow situations with litter input is likely to alter litter processing. Based on results from Aquashift period 1, we hypothesise change of the invertebrate shredder community and shift among microbial and invertebrate leaf processing. These will change the dynamics of the energy supply of the benthic food web. In pools of summer-dry streams we will expose litter-bags (Alnus glutinosa (L.) Gaertn.) to assess mass loss, microbial colonisation (fungi, bacteria) and invertebrate shredding of leaves. Stepwise exclusion of larger invertebrates from litter-bags will assess the significance of suggested shift from dominance of large shredder (Gammarus) to small invertebrates (Chironomidae). In microcosm experiments we want to investigate the effect of factor combinations found in fragmented pools on microbial and invertebrate leaf processing. A leaf decay simulation model will be build in joint activity with the University Braunschweig to test significance of environmental factors. Linking the population dynamics model of Gammarus pulex at Univ. Braunschweig, the dynamics of FPOM production from leaves will be predicted under various climate change scenarios.

Trophic interactions in the soil of rice-rice and rice-maize cropping systems

Das Projekt "Trophic interactions in the soil of rice-rice and rice-maize cropping systems" wird vom Umweltbundesamt gefördert und von Universität Gießen, Institut für Allgemeine und Spezielle Zoologie, Bereich Tierökologie und Spezielle Biologie durchgeführt. Subproject 3 will investigate the effect of shifting from continuously flooded rice cropping to crop rotation (including non-flooded systems) and diversified crops on the soil fauna communities and associated ecosystem functions. In both flooded and non-flooded systems, functional groups with a major impact on soil functions will be identified and their response to changing management regimes as well as their re-colonization capability after crop rotation will be quantified. Soil functions corresponding to specific functional groups, i.e. biogenic structural damage of the puddle layer, water loss and nutrient leaching, will be determined by correlating soil fauna data with soil service data of SP4, SP5 and SP7 and with data collected within this subproject (SP3). In addition to the field data acquired directly at the IRRI, microcosm experiments covering the broader range of environmental conditions expected under future climate conditions will be set up to determine the compositional and functional robustness of major components of the local soil fauna. Food webs will be modeled based on the soil animal data available to gain a thorough understanding of i) the factors shaping biological communities in rice cropping systems, and ii) C- and N-flow mediated by soil communities in rice fields. Advanced statistical modeling for quantification of species - environment relationships integrating all data subsets will specify the impact of crop diversification in rice agro-ecosystems on soil biota and on the related ecosystem services.

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