Im letzten Jahrzehnt war der grönländische Eisschild mehreren Extremereignissen ausgesetzt, mit teils unerwartet starken Auswirkungen auf die Oberflächenmassebilanz und den Eisfluss, insbesondere in den Jahren 2010, 2012 und 2015. Einige dieser Schmelzereignisse prägten sich eher lokal aus (wie in 2015), während andere fast die gesamte Eisfläche bedeckten (wie in 2010).Mit fortschreitendem Klimawandel ist zu erwarten, dass extreme Schmelzereignisse häufiger auftreten und sich verstärken bzw. länger anhalten. Bisherige Projektionen des Eisverlustes von Grönland basieren jedoch typischerweise auf Szenarien, die nur allmähliche Veränderungen des Klimas berücksichtigen, z.B. in den Representative Concentration Pathways (RCPs), wie sie im letzten IPCC-Bericht genutzt wurden. In aktuellen Projektionen werden extreme Schmelzereignisse im Allgemeinen unterschätzt - und welche Konsequenzen dies für den zukünftigen Meeresspiegelanstieg hat, bleibt eine offene Forschungsfrage.Ziel des vorgeschlagenen Projektes ist es, die Auswirkungen extremer Schmelzereignisse auf die zukünftige Entwicklung des grönländischen Eisschildes zu untersuchen. Dabei werden die unmittelbaren und dauerhaften Auswirkungen auf die Oberflächenmassenbilanz und die Eisdynamik bestimmt und somit die Beiträge zum Meeresspiegelanstieg quantifiziert. In dem Forschungsprojekt planen wir zudem, kritische Schwellenwerte in der Häufigkeit, Intensität sowie Dauer von Extremereignissen zu identifizieren, die - sobald sie einmal überschritten sind - eine großräumige Änderung in der Eisdynamik auslösen könnten.Zu diesem Zweck werden wir die dynamische Reaktion des grönländischen Eisschilds in einer Reihe von Klimaszenarien untersuchen, in denen extreme Schmelzereignisse mit unterschiedlicher Wahrscheinlichkeit zu bestimmten Zeitpunkten auftreten, und die Dauer und Stärke prognostisch variiert werden. Um indirekte Effekte durch verstärktes submarines Schmelzen hierbei berücksichtigen zu können, werden wir das etablierte Parallel Ice Sheet Model (PISM) mit dem Linearen Plume-Modell (LPM) koppeln. Das LPM berechnet das turbulente submarine Schmelzen aufgrund von Veränderungen der Meerestemperatur und des subglazialen Ausflusses. Es ist numerisch sehr effizient, so dass das gekoppelte PISM-LPM Modell Ensemble-Läufe mit hoher Auflösung ermöglicht. Folglich kann eine breite Palette von Modellparametern und Klimaszenarien in Zukunftsprojektionen in Betracht gezogen werden.Mit dem interaktiv gekoppelten Modell PISM-LPM werden wir den Beitrag Grönlands zum Meeresspiegelanstieg im 21. Jahrhundert bestimmen, unter Berücksichtigung regionaler Veränderungen von Niederschlag, Oberflächen- und Meerestemperaturen, und insbesondere der Auswirkungen von Extremereignissen. Ein Hauptergebnis wird eine Risikokarte sein, die aufzeigt, in welchen kritischen Regionen Grönlands zukünftige extreme Schmelzereignisse den stärksten Eisverlust zur Folge hätten.
Das Projekt ÖkoKauf der Stadt Wien hat es sich zum Ziel gesetzt, durch die Erstellung von ökologischen Kriterien, Pilotprojekte und durch Bewusstseinsarbeit das Beschaffungswesen im Magistrat Wien weiter zu ökologisieren. In diesem Rahmen widmete sich der Arbeitskreis 'Desinfektionsmittel unter der Leitung der Wiener Umweltanwaltschaft (WUA) der Aufgabe, für Hygienefachleute ein Instrument zur Beurteilung der Auswirkungen von Desinfektionsmitteln auf Gesundheit und Umwelt zu erstellen. Das Österreichische Ökologie-Institut führte eine Daten- und Literaturrecherche durch, das Umweltbundesamt nahm ergän-zende ökotoxikologische Tests an Wirkstoffen und -produkten vor und 'die umweltberatung ermittelte stationsbezogene Desinfektionsmittelverbräuche in Wiener Krankenanstalten. Die Recherche- und Testergebnisse zu Desinfektionsmittelwirkstoffen und -produkten wurden in einer vom IFZ konzipierten und von der Magistratsabteilung 14 realisierten Datenbank zusammengefasst. Um die ökotoxikologischen Produkteigenschaften vergleichbar zu machen, wurde vom IFZ ein Bewertungsraster entwickelt und in die Datenbank integriert. Dabei werden nachteilige Wirkungen auf die Gesundheit anhand von vier Wirkungskategorien erfasst: Akute Giftigkeit; Reizwirkung auf die Haut; Sensibilisierung, allergenes Potenzial sowie Erbgutschädigende, krebserzeugende und fruchtschädigende Eigenschaften. Zusammen mit der Berücksichtigung des Verhaltens in Oberflächengewässern (Abbauverhalten, Bioakkumulationspotenzial, Toxizität für Wasserorganismen) sowie dem Verhalten in Kläranlagen werden insgesamt sechs Bewertungszahlen generiert, die auf einer Skala von 1 (vernachlässigbar) bis 5 (sehr hoch) das gesamte Gefährdungsprofil des Stoffes beschreiben sollen. Das Gefährdungsprofil eines Handelsproduktes errechnet sich aus den Gefährdungsprofilen der darin enthaltenen Wirkstoffe anhand eines Algorithmus: Dabei wird die Annahme getroffen, dass die Produkteigenschaften von der Konzentration der darin enthaltenen Wirkstoffe abhängen. Bei der Bewertung ist außerdem zu gewährleisten, dass ein Wirkstoff mit einem hohen Gefährdungspotenzial angemessen berücksichtigt wird, auch und gerade wenn seine Konzentration im Produkt gering ist. In der Literatur wird dazu eine logarithmische Skalierung vorgeschlagen. Die Bewertung berücksichtigt derzeit die Wirkstoffe sowie Anwendungsverdünnungen. Die Zusammenfassung der Produkte in Verwendungs- bzw. Expositionskategorien ermöglicht letztlich eine vergleichende Bewertung. Da das Bewertungsraster gerade auf eine vergleichende Bewertung von Produkten abzielt, unterliegt er einer ständigen kritischen Diskussion, die auch häufig von den Herstellern geführt wird. Dieser Umstand sowie das Faktum von Produktlebenszyklen erfordern ein ständiges Update der in der Datenbank enthaltenen Informationen und eine Anpassung des Bewertungsmodells an den aktuellen Stand von Forschung sowie Standards der Stoff- und Produktpolitik.
Shallow groundwater of the huge deltaic systems of Asia like the Red River Delta in Vietnam is often enriched in inorganic arsenic (As), threatening the health of millions of residents. The massive abstraction of groundwater in these areas locally causes an irreversible mixing of arsenic-free groundwater resources with arsenic-rich groundwater. Increased concentrations of competitive anions, especially phosphate (PO43-), decrease the immobilization capacity of the sediments. During transport, the mobility of dissolved As in local aquifers is strongly influenced by adsorption to sedimentary and ubiquitously occurring iron(oxyhydr)oxides. Additionally, arsenic-rich groundwater is often enriched in reduced iron (Fe2+) as well, which is capable to react with iron(oxyhydr)oxides, thereby inducing mineral transformations. Such transformations permanently affect the arsenic adsorption and immobilization capacity of the sediments.Within the scope of this research project, the underlying mechanisms related to As transport and the resulting threat to arsenic-free groundwater resources will be characterized in cooperation with the Swiss Federal Institute of Aquatic Science and Technology (Eawag). The research concept aims at assessing the complex interactions within the arsenic-iron-phosphate-system under field conditions at a study site next to the Red River. First, filtration experiments using local groundwater enriched in As and PO43- will be used to determine the As adsorption capacity of different and previously geochemically characterized iron(oxyhydr)oxides. In a second step, sample carrier containing As loaded iron(oxyhydr)oxides will be introduced into surface near aquifer parts of the study site (via existing groundwater monitoring wells). These samples will be exposed to local groundwater characterized by increased As, Fe2+ and PO43- concentrations for the following nine months. Using the in situ exposition of predefined iron(oxyhydr)oxides, it will be possible to distinguish potential mineral transformations and their influences on the As immobilization capacity of the respective iron(oxyhydr)oxides. By combining the results and outcomes of the field experiments, new and important conclusions regarding the mobility of As can be drawn. The data can be used to create a hydrochemical transport model describing reactive As transport within the investigation area. In addition, the results of the in situ exposition experiments will allow to draw conclusions in respective to the long term As immobilization capacity of different iron(oxyhydr)oxides, which is an essential information regarding in situ decontamination techniques.
The proposal addresses the potential of subsoil to contribute to K nutrition of crops. More specifically we will address the processes controlling release of K from interlayer of 2:1 clay minerals as this is expected to be the dominant K fraction in the subsoil. While it has been shown in the past that this so called 'non-exchangeable' K can be released due to root activity, there are controversial results concerning the role of soil solution K concentration in the rhizosphere required to trigger the process. Likewise little information is available about the concentration dynamics of other cations (NH4, Ca) in the rhizosphere and their impact on K release and vermiculitization supposed to be associated with this process. Model studies with substrate from the central field trial will be conducted in compartment systems equipped with micro suction cups. The measurement of dynamic changes of soil solution composition with increasing distance from the root surface will be combined with investigations of changes in mineralogy by XRD, TEM and SEM-EDX. Changes of mineralogy as a result of plant induced K release from interlayer will also be studied on bulk soil and rhizosphere samples collected within the central field and the central microcosm experiment and with mineral bags exposed in the field during a cropping cycle. Finally, X-ray CT will be used to access changes in soil texture, i.e. clay distribution around roots and the temporal spread of roots in biopores which is a prerequisite for K uptake from such structures.
In June 2010, the DLR Group of Systems Analysis started an investigation about innovative financing of Concentrating Solar Power Plants (CSP) in countries of the Middle East and North Africa. We found a possible strategy for the market introduction of concentrating solar power (CSP) plants in the Middle East and North Africa (MENA) that will not require considerable subsidization and will not constitute a significant burden for electricity consumers in the region. In the first section, the paper explains the need of MENA countries for sustainable supply of electricity and calculates the cost of electricity for a model case country. In the second part, the cost development of concentrating solar power plants is calculated on the basis of expectations for the expansion of CSP on a global level. After that, the challenges for the market introduction of CSP in MENA are explained. Finally, we present a strategy for the market introduction of CSP in MENA, removing the main barriers for financing and starting market introduction in the peak load and the medium load segment of power supply. The paper explains why long-term power purchase agreements (PPA) for CSP should be calculated on the basis of avoided costs, starting in the peak load segment. Such PPA are not yet available, the paper aims to convince policy makers to introduce them. The attached power point file shows some examples of time series of load and supply by CSP in the different load segments and shows the graphs used in the report. The attached Excel Sheet gives the time series of load and supply by CSP for the different load segments for a total reference year.
Methane (CH4) is a major greenhouse gas of which the atmospheric concentration has more than doubled since pre-industrial times. Soils can act as both, source and sink for atmospheric CH4, while upland forest soils generally act as CH4 consumers. Oxidation rates depend on factors influenced by the climate like soil temperature and soil moisture but also on soil properties like soil structure, texture and chemical properties. Many of these parameters directly influence soil aeration. CH4 oxidation in soils seems to be controlled by the supply with atmospheric CH4, and thus soil aeration is a key factor. We aim to investigate the importance of soil-gas transport-processes for CH4 oxidation in forest soils from the variability the intra-site level, down to small-scale (0.1 m), using new approaches of field measurements. Further we will investigate the temporal evolution of soil CH4 consumption and the influence of environmental factors during the season. Based on previous results, we hypothesize that turbulence-driven pressure-pumping modifies the transport of CH4 into the soil, and thus, also CH4 consumption. To improve the understanding of horizontal patterns of CH4 oxidation we want to integrate the vertical dimension on the different scales using an enhanced gradient flux method. To overcome the constraints of the classical gradient method we will apply gas-diffusivity measurements in-situ using tracer gases and Finite-Element-Modeling. Similar to the geophysical technique of Electrical Resistivity Tomography we want to develop a Gas Diffusivity Tomography. This will allow to derive the three-dimensional distribution of soil gas diffusivity and methane oxidation.
Glendonites are pseudomorphs after the mineral ikaite (CaCO3 x 6H2O) and composed of calcite (CaCO3). In the past, they have been used as a paleo-thermometer because the primary mineral ikaite, according to observations and experiments, seems to be formed at temperatures near freezing, high alkalinity and high phosphate concentrations in marine sediments. An enigmatic occurrence of the largest glendonites known world-wide, in the Early Eocene Fur Formation of northwestern Denmark offers the unique possibility to shed more light on the actual mechanism and controlling parameters of ikaite formation. Right in the aftermath of the Paleocene-Eocene thermal maximum, a time known for its global pertubation in the global carbon cycle, the formation of authigenic calcium carbonate concretions start in the Fur Formation. In a specific stratigraphic interval inbetween these concretions, the glendonites can be found. We will investigate if termperature changes or changes in geochemical parameters of the Danish Basin caused the sudden formation of ikaite during a time interval that was based on known paleoclimatic reconstructions (semi tropic) not favorable for ikaite formation.
Steroid hormones are essential in orchestrating oocyte maturation, i.e. estrogens of follicular origin support the development of the female gamete and fertilization. In this project the concentration of free and conjugated estrogens during follicular development will be analysed and compared to local concentrations in the developing follicle. Cattle are suitable animal models because of the accessibility and suitability for frequent examination and sampling. Furthermore, it has been useful for understanding several features of human reproduction including follicular dynamics, the fate of the emerging follicles is orchestrated mainly by gonadotropins and steroid hormones in a similar manner. Ovarian SULT1E1 participates locally in the regulation of follicular estrogen activity. The ESTcatalysed down-regulation of estrogen activity enables normal ovulation. Conversely, sulfoconjugated estrogens may also be precursors of the production of free estrogens depending on estrogen sulfatase (StS) acitivity. In mammals, follicular luteinisation/ovulation is triggered by a surge in LH and is characterised by numerous physical and biochemical changes, including the decreased production of estradiol (E2). This loss in E2 biosynthetic capacity has been explained by a marked decrease in the expression of key steroidogenic enzymes involved in the follicular production of active estrogens. However, little is known about the regulation of enzymes/proteins responsible for the inactivation and elimination of estrogens, as mediated for example by EST during this period.
Agriculture is the major contributor of nitrogen to ecosystems, both by organic and inorganic fertilizers. Percolation of nitrate to groundwater and further transport to surface waters is assumed to be one of the major pathways in the fate of this nitrogen. The quantification of groundwater and associated nitrate flux to streams is still challenging. In particular because we lack understanding of the spatial distribution and temporal variability of groundwater and associated NO3- fluxes. In this preliminary study we will focus on the identification and quantification of groundwater and associated nitrate fluxes by combining high resolution distributed fiber-optic temperature sensing (DTS) with in situ UV photometry (ProPS). DTS is a new technique that is capable to measure temperature over distances of km with a spatial resolution of ca1 m and an accuracy of 0.01 K. It has been applied successfully to identify and quantify sources of groundwater discharge to streams. ProPS is a submersible UV process photometer, which uses high precision spectral analyses to provide single substance concentrations, in our case NO3-, at minute intervals and a detection limit of less than 0.05 mg l-1 (ca.0.01 mg NO3--Nl-1). We will conduct field experiments using artificial point sources of lateral inflow to test DTS and ProPS based quantification approaches and estimate their uncertainty. The selected study area is the Schwingbach catchment in Hessen, Germany, which has a good monitoring infrastructure. Preliminary research on hydrological fluxes and field observations indicate that the catchment favors the intended study.
Organotin and especially butyltin compounds are used for a variety of applications, e.g. as biocides, stabilizers, catalysts and intermediates in chemical syntheses. Tributyltin (TBT) compounds exhibit the greatest toxicity of all organotins and have even been characterized as one of the most toxic groups of xenobiotics ever produced and deliberately introduced into the environment. TBT is not only used as an active biocidal compound in antifouling paints, which are designed to prevent marine and freshwater biota from settlement on ship hulls, harbour and offshore installations, but also as a biocide in wood preservatives, textiles, dispersion paints and agricultural pesticides. Additionally, it occurs as a by-product of mono- (MBT) and dibutyltin (DBT) compounds, which are used as UV stabilizer in many plastics and for other applications. Triphenyltin (TPT) compounds are also used as the active biocide in antifouling paints outside Europe and furthermore as an agricultural fungicide since the early 1960s to combat a range of fungal diseases in various crops, particularly potato blight, leaf spot and powdery mildew on sugar beet, peanuts and celery, other fungi on hop, brown rust on beans, grey moulds on onions, rice blast and coffee leaf rust. Although the use of TBT and TPT was regulated in many countries world-wide from restrictions for certain applications to a total ban, these compounds are still present in the environment. In the early 1970s the impact of TBT on nontarget organisms became apparent. Among the broad variety of malformations caused by TBT in aquatic animals, molluscs have been found to be an extremely sensitive group of invertebrates and no other pathological condition produced by TBT at relative low concentrations rivals that of the imposex phenomenon in prosobranch gastropods speaking in terms of sensitivity. TBT induces imposex in marine prosobranchs at concentrations as low as 0,5 ng TBT-Sn/L. Since 1993, for the littorinid snail Littorina littorea a second virilisation phenomenon, termed intersex, is known. In female specimens affected by intersex the pallial oviduct is transformed of towards a male morphology with a final supplanting of female organs by the corresponding male formations. Imposex and intersex are morphological alterations caused by a chronic exposure to ultra-trace concentrations of TBT. A biological effect monitoring offers the possibility to determine the degree of contamination with organotin compounds in the aquatic environment and especially in coastal waters without using any expensive analytical methods. Furthermore, the biological effect monitoring allows an assessment of the existing TBT pollution on the basis of biological effects. Such results are normally more relevant for the ecosystem than pure analytical data. usw.
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