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Schwerpunktprogramm (SPP) 1689: Climate Engineering: Risiken, Herausforderungen, Möglichkeiten?, Klima-Engineering über Land: Umfassende Evaluierung von Auswirkungen terrestrischer Carbon-Dioxide-Removal-Methoden auf das Erdsystem (CE-LAND+)

Methoden des terrestrischen Carbon Dioxide Removal (tCDR) wie Aufforstung und Biomasseplantagen werden zuweilen als effektive, 'grüne' und sichere Varianten des Klimaengineering (CE) verstanden wegen ihrer Möglichkeit, die natürliche CO2-Aufnahme durch die Biosphäre zu erhöhen, und ihrer denkbaren ökonomischen Tragfähigkeit. Erkenntnisse aus der ersten Phase des CE-LAND-Projekts legen indes nahe, dass tCDR aufgrund schwieriger erdsystemischer und ethischer Fragen ebenso kontrovers wie andere CE-Methoden ist. CO2-Budgetierungen und rein ökonomische Bewertungen sind daher um profunde Analysen der natürlichen Begrenzungen, der Auswirkungen auf das Erdsystem mit damit verbundenen Unsicherheiten, der Tradeoffs mit anderen Land- und Wassernutzungen und der weitreichenden ethischen Implikationen von tCDR-Maßnahmen zu ergänzen. Analysen hypothetischer Szenarien der ersten Projektphase zeigen, dass effektives tCDR die Umwidmung großer Flächen voraussetzt, womit schwierige Abwägungsprozesse mit anderen Landnutzungen verbunden wären. Darüber hinaus zeigt sich, dass signifikante Nebenwirkungen im Klimasystem (außer der bezweckten Senkung der Weltmitteltemperatur) und in terrestrischen biogeochemischen Kreisläufen aufträten. CE-LAND+ bietet eine tiefergehende quantitative, räumlich explizite Evaluierung der nicht-ökonomischen Kosten einer Biosphärentransformation für tCDR. Potentielle Tradeoffs und Impakts wie auch die systematische Untersuchung von Unsicherheiten in ihrer Abschätzung werden mit zwei Vegetationsmodellen, einem Erdsystemmodell und, neu im Projekt, dynamischen Biodiversitätsmodellen analysiert. Konkret wird CE-LAND+ bisher kaum bilanzierte Tradeoffs untersuchen: einerseits zwischen der Maximierung der Flächennutzung für tCDR bzw. Biodiversitätsschutz, andererseits zwischen der Maximierung der Süßwasserverfügbarkeit für tCDR bzw. Nahrungsmittelproduktion sowie Flussökosysteme. Auch werden die (in)direkten Auswirkungen veränderten Klimas und tCDR-bedingter Landnutzungsänderungen auf Wasserknappheit (mit diversen Metriken und unter Annahme verschiedener Varianten des Wassermanagements) und Biodiversität quantifiziert. Die Tradeoffs und Impakts werden im Kontext von neben der Bekämpfung des Klimawandels formulierten globalen Nachhaltigkeitszielen - Biodiversitätsschutz, Wasser- und Ernährungssicherheit interpretiert - was sonst nicht im Schwerpunktprogramm vermittelt wird. Ferner wird das Projekt zu besserem Verständnis und besserer Quantifizierung von Unsicherheiten von tCDR-Effekten unter zukünftigem Klima beitragen. Hierzu untersucht es modellstrukturbedingte Unterschiede, Wachstum und Mortalität von tCDR-Pflanzungen unter wärmeren und CO2-reicheren Bedingungen und Wechselwirkungen zwischen tCDR-bezogenen Landnutzungsaktivitäten und Klima. Schließlich wird CE-LAND+ in Kooperationen innerhalb des Schwerpunktprogramms und mit einer repräsentativen Auswahl von Szenarien zur Evaluierung tCDR-bedingter Tradeoffs aus umweltethischer Sicht beitragen.

Residence times across scales: from plot to catchment scale

Residence times is a key signature to characterize flow and transport at all temporal and spatial scales in different hydrological compartments. It is assumed that the spatial organisation of the landscape controls space-time organisation of the water cycle and related processes and hence the residence time. Combining flux and residence concentration data of natural tracers in water, stable isotopes, and artificial tracers will allow us to predict residence time and flow pathways in the different hydrological compartments as well as integrative for entire watersheds. We will investigate with different methods the fingerprint of hydrological processes found in the signal of isotopic composition and natural and artificial tracers of soil, ground and stream water in space and time. The temporal variability of isotopes in soil water, groundwater and stream water will be combined to benchmark transport and flow models and to derive a new functional form of short to long-term transit time distributions. The spatial patterns of stable isotopes in the saturated and unsaturated zone will be used to derive long-term flow pathways, mixing patterns and the proportion of evaporation to transpiration. Artificial tracer experiments using salt and electric resistivities will vizualize and quantify internal flow pathways in particular preferential flow pathways.

Adaptations and counter-adaptations in the coevolutionary arms race of a baculovirus and its insect host

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.

Water use characteristics of bamboo (South China)

Bamboos (Poaceae) are widespread in tropical and subtropical forests. Particularly in Asia, bamboos are cultivated by smallholders and increasingly in large plantations. In contrast to trees, reliable assessments of water use characteristics for bamboo are very scarce. Recently we tested a set of methods for assessing bamboo water use and obtained first results. Objectives of the proposed project are (1) to further test and develop the methods, (2) to compare the water use of different bamboo species, (3) to analyze the water use to bamboo size relationship across species, and (4) to assess effects of bamboo culm density on the stand-level transpiration. The study shall be conducted in South China where bamboos are very abundant. It is planned to work in a common garden (method testing), a botanical garden (species comparison, water use to size relationship), and on-farm (effects of culm density). Method testing will include a variety of approaches (thermal dissipation probes, stem heat balance, deuterium tracing and gravimetry), whereas subsequent steps will be based on thermal methods. The results may contribute to an improved understanding of bamboo water use characteristics and a more appropriate management of bamboo with respect to water resources.

DFG Trilateral collaboration Deutschland-Israel-Palestine: Wastewater from Olive Oil Mills in Israel and Palestine: Interactions with Soil, Organic Contaminants and Mechanisms of Incorporation into Soil

Due to the often practised uncontrolled disposal into the environment, olive oil production wastewater (OPWW) is presently a serious environmental problem in Palestine and Israel. The objectives of this interdisciplinary trilateral research project are (i) to understand the mechanisms of influence of the olive oil production wastewater on soil wettability, water storage, interaction with organic agrochemicals and pollutants; (ii) monitor short-term and long-term effects of OPWW land application in model laboratory and field experiments; (iii) identify the components responsible for unwanted changes in soil properties and (iv) analyse the mechanisms of association of OPWW OM with soil, the interplay between climatic conditions, pH, presence of multivalent cations and the resulting effects of land application. Laboratory incubation experiments, field experiments and new experiments to study heat-induced water repellency will be conducted to identify responsible OPWW compounds and mechanisms of interaction. Samples from field experiments and laboratory experiments are investigated using 3D excitation-emission fluorescence spectroscopy, thermogravimetry-differential thermal analysis-mass spectrometry (TGA-DSC-MS), LC-MS and GC-MS analyses. We will combine thermal decomposition profiles from OPWW and OPWW-treated soils in dependence of the incubation status using TGA-DSC-MS, contact angle measurements, sorption isotherms and the newly developed time dependent sessile drop method (TISED). The resulting process understanding will open a perspective for OPWW wastewater reuse in small-scale and family-scale olive oil production busi-nesses in the Mediterranean area and will further help to comprehend the until now not fully un-ravelled effects of wastewater irrigation on soil water repellency.

Forschergruppe (FOR) 1740: Ein neuer Ansatz für verbesserte Abschätzungen des atlantischen Frischwasserhaushalts und von Frischwassertransporten als Teil des globalen Wasserkreislaufs, Variation of the fresh water in the western Nordic Seas

The goal of this project is to capture and analyse fluctuations of the fresh water in the western Nordic Seas and to understand the related processes. The East Greenland Current in the Nordic Seas constitutes an important conduit for fresh water exiting the Arctic Ocean towards the North Atlantic. The Arctic Ocean receives huge amounts of fresh water by continental runoff and by import from the Pacific Ocean. Within the Arctic Ocean fresh water is concentrated at the surface through sea ice formation. The East Greenland Current carries this fresh water in variable fractions as sea ice and in liquid form; part of it enters the central Nordic Seas, via branching of the current and through eddies. It controls the intensity of deep water formation and dilutes the water masses which result from convection. The last decades showed significant changes of the fresh water yield and distribution in the Nordic Seas and such anomalies were found to circulate through the North Atlantic. In this project the fresh water inventory, its spatial distribution and its pathways between the East Greenland Current and the interior Greenland and Icelandic seas shall be captured by autonomous glider missions. The new measurements and existing data will, in combination with the modeling work of the research group, serve as basis for understanding the causes of the fresh water variability and their consequences for the North Atlantic circulation and deep water formation.

Unraveling the genetic architecture of winter hardiness and quality traits in durum by genome wide and canidate gene based association mapping

Durum wheat is mainly grown as a summer crop. An introduction of a winter form failed until now due to the difficulty to combine winter hardiness with required process quality. Winter hardiness is a complex trait, but in most regions the frost tolerance is decisive. Thereby a major QTL, which was found in T. monococcum, T.aestivum, H. vulgare and S.cereale on chromosome 5, seems especially important. With genotyping by sequencing it is now possible to make association mapping based on very high dense marker maps, which delivers new possibilities to detect main and epistatic effects. Furthermore, new sequencing techniques allow candidate gene based association mapping. The main aim of the project is to unravel the genetic architecture of frost tolerance and quality traits in durum. Thereby, the objectives are to (1) determine the genetic variance, heritability and correlations among frost tolerance and quality traits, (2) examine linkage disequilibrium and population structure, (3) investigate sequence polymorphism at candidate genes for frost tolerance, and (4) perform candidate gene based and genome wide association mapping.

The importance of peripheral oceanic processes in the Labrador Sea for the Atlantic meridional overturning circulation

The Labrador Sea is one of the few places in the world ocean, where deep water formation takes place. This water is exported from the Labrador Sea to become part of the southward branch of the meridional overturning circulation. Previous observational work has largely focused on the role of deep convection in the interior of the Labrador Sea. Recent evidence from observations and numerical ocean models specifically indicate that processes near the ocean boundaries might be most relevant for both Eulerian downwelling of waters in the Labrador Sea and the fast export of newly transformed waters. We propose to analyze mooring based observations at the western margin of the Labrador Sea together with high resolution numerical model simulations to understand the role both processes play for the meridional overturning circulation in the subpolar North Atlantic. Specifically, we want to test (i) if (and where) downwelling occurs along the margins of the Labrador Sea, (ii) how downwelling relates to the seasonal evolution of convection and eddy activity, (iii) how fast waters newly transformed near the western margin of the Labrador Sea are exported, and (iv) how the two processes (downwelling, fast export) affect the temporal variability of the Atlantic meridional overturning circulation.

Der Einfluss der SML auf die Spurengasbiogeochemie und den Ozean-Atmosphäre-Gasaustausch

Labor- und Feldstudien zeigen, dass die Oberflächengrenzschicht des Ozeans (â€Ìsurface microlayerâ€Ì, kurz SML) die biogeochemischen Kreisläufe von klimaaktiven und atmosphärisch wichtigen Spurengasen wie Kohlenstoffdioxid (CO2), Kohlenstoffmonoxid (CO), Methan (CH4), Lachgas (N2O) und Dimethylsulfid (DMS) stark beeinflusst: (i) Jüngste Studien aus den PASSME- und SOPRAN-Projekten haben hervorgehoben, dass Anreicherungen von oberflächenaktiven Substanzen (d.h. Tensiden) einen starken (dämpfenden) Effekt sowohl auf die CO2- als auch auf die N2O-Flüsse über die SML/Atmosphären-Grenzfläche hinweg haben und (ii) Spurengase können durch (mikro)biologische oder (photo)chemische Prozesse in der SML produziert und verbraucht werden. Daher kann der oberste Teil des Ozeans, einschließlich der SML, verglichen mit dem Wasser, das in der Mischungsschicht unterhalb der SML zu finden ist, eine bedeutende Quelle oder Senke für diese Gase sein, was von sehr großer Relevanz für die Forschungseinheit BASS ist. Die Konzentrationen von CO2, N2O und anderen gelösten Gasen in der SML (oder den oberen Zentimetern des Ozeans) unterscheiden sich nachweislich von ihren Konzentrationen unterhalb der SML. Typischerweise werden die Nettoquellen und -senken wichtiger atmosphärischer Spurengase mit Konzentrationen berechnet, die in der Mischungsschicht gemessen wurden und mit Gasaustauschgeschwindigkeiten, die die SML nicht berücksichtigen. Diese Diskrepanzen führen zu falsch berechneten Austauschflüssen, die in der Folge zu großen Unsicherheiten in den Berechnungen der Klima-Antrieben und der Luftqualität in Erdsystemmodellen führen können. Durch die Verknüpfung unserer Spurengasmessungen mit Messungen von (i) der Dynamik und den molekularen Eigenschaften der organischen Materie und speziell des organischen Kohlenstoffs (SP1.1; SP1.5), (ii) der biologischen Diversität und der Stoffwechselaktivität (SP1.2), (iii) den optischen Eigenschaften der organischen Materie (SP1.3), (iv) der photochemischen Umwandlung der organischen Materie (SP1.4) und (v) den physikalischen Transportprozessen (SP2.3) werden wir ein umfassendes Verständnis darüber erlangen, wie die SML die Variabilität der Spurengasflüsse beeinflusst.

Biogeochemical Processes in Tropical Soils

In recent years science has taken an increased interest in mineralization processes in tropical soils in particular under minimal tillage operations. Plant litter quality and management strongly affect mineralization-nitrification processes in soil and hence the fate of nitrogen in ecosystems and the environment. Plant secondary metabolites like lignin and polyphenols are poorly degradable and interact with proteins (protein binding capacity) and hence protect them from microbial attack. Nitrification, a microbiological process, directly and indirectly influences the efficiency of recovery of N in the vegetation as well as the loss of N (through denitrification and leaching) causing environmental pollution to water bodies and contributes to global warming (e.g. the greenhouse gas N2O is emitted as a by-product of nitrification and denitrification). Nitrifiers comprise a relatively narrow species diversity (at least as known to date) and are generally thought to be sensitive to low soil pH and stress. Despite these properties nitrification occurs in acid tropical soils with high levels of aluminium and manganese. Thus the main objective of the project will be the identification of micro-organisms and mechanisms responsible for mineralization-nitrification processes in acid tropical soils and the influence of long-term litter input of different chemical qualities and minimal tillage options. The project will include the use of stable isotopes (15N, 13C), mass spectrometry, gas chromatography (CO2, N2O), biochemical methods (PLFA) and molecular biology (16s rRNA., PCR, DGGE)

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