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Quantification of small-scale physicochemical properties of intact macropore surfaces in structured soils

In structured soils, the interaction of percolating water and reactive solutes with the soil matrix is mostly restricted to the surfaces of preferential flow paths. Flow paths, i.e., macropores, are formed by worm burrows, decayed root channels, cracks, and inter-aggregate spaces. While biopores are covered by earthworm casts and mucilage or by root residues, aggregates and cracks are often coated by soil organic matter (SOM), oxides, and clay minerals especially in the clay illuviation horizons of Luvisols. The SOM as well as the clay mineral composition and concentration strongly determine the wettability and sorption capacity of the coatings and thus control water and solute movement as well as the mass exchange between the preferential flow paths and the soil matrix. The objective of this proposal is the quantitative description of the small-scale distribution of physicochemical properties of intact structural surfaces and flow path surfaces and of their distribution in the soil volume. Samples of Bt horizons of Luvisols from Loess will be compared with those from glacial till. At intact structural surfaces prepared from soil clods, the spatial distribution (mm-scale) of SOM and clay mineral composition will be characterized with DRIFT (Diffuse reflectance infrared Fourier transform) spectroscopy using a self-developed mapping technique. For samples manually separated from coated surfaces and biopore walls, the contents of organic carbon (Corg) and the cation exchange capacity (CEC) will be analyzed and related to the intensities of specific signals in DRIFT spectra using Partial Least Square Regression (PLSR) analysis. The signal intensities of the DRIFT mapping spectra will be used to quantify the spatial distribution of Corg and CEC at these structural surfaces. The DRIFT mapping data will also be used for qualitatively characterizing the small scale distribution of the recalcitrance, humification, and microbial activity of the SOM from structural surfaces. The clay mineral composition of defined surface regions will be characterized by combining DRIFT spectroscopic with X-ray diffractometric analysis of manually separated samples. Subsequently, the spatial distribution of the clay mineral composition at structural surfaces will be determined from the intensities of clay mineral-specific signals in the DRIFT mapping spectra and exemplarily compared to scanning electron microscopic and infrared microscopic analysis of thin sections and thin polished micro-sections. The three-dimensional spatial distribution of the total structural surfaces in the volume of the Bt horizons will be quantified using X-ray computed tomography (CT) analysis of soil cores. The active preferential flow paths will be visualized and quantified by field tracer experiments. These CT and tracer data will be used to transfer the properties of the structural surfaces characterized by DRIFT mapping onto the active preferential flow paths in the Bt horizons.

Spatial heterogeneity and substrate availability as limiting factors for subsoil C-turnover

In subsoils, organic matter (SOM) concentrations and microbial densities are much lower than in topsoils and most likely highly heterogeneously distributed. We therefore hypothesize, that the spatial separation between consumers (microorganisms) and their substrates (SOM) is an important limiting factor for carbon turnover in subsoils. Further, we expect microbial activity to occur mainly in few hot spots, such as the rhizosphere or flow paths where fresh substrate inputs are rapidly mineralized. In a first step, the spatial distribution of enzyme and microbial activities in top- and subsoils will be determined in order to identify hot spots and relate this to apparent 14C age, SOM composition, microbial community composition and soil properties, as determined by the other projects within the research unit. In a further step it will be determined, if microbial activity and SOM turnover is limited by substrate availability in spatially distinct soil microsites. By relating this data to root distribution and preferential flow paths we will contribute to the understanding of stabilizing and destabilizing processes of subsoil organic matter. As it is unclear, at which spatial scale these differentiating processes are effective, the analysis of spatial variability will cover the dm to the mm scale. As spatial segregation between consumers and substrates will depend on the pore and aggregate architecture of the soil, the role of the physical integrity of these structures on SOM turnover will also be investigated in laboratory experiments.

Schwerpunktprogramm (SPP) 1158: Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; Bereich Infrastruktur - Antarktisforschung mit vergleichenden Untersuchungen in arktischen Eisgebieten, Investigation of mechanism driving glacial/interglacial variability in stratification/mixing and biological productivity of the Pacific Southern Ocean and potential implications on air-sea CO2-exchange: synthesis of climate and ocean biogeochemical modeling with paleoceanographic reconstructions

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

GTS Bulletin: ISMD05 EDZW - Observational data (Binary coded) - BUFR (details are described in the abstract)

The ISMD05 TTAAii Data Designators decode as: T1 (I): Observational data (Binary coded) - BUFR T1T2 (IS): Surface/sea level T1T2A1 (ISM): Main synoptic observations from fixed land stations A2 (D): 90°E - 0° northern hemisphere(The bulletin collects reports from stations: 10161;Boltenhagen;10168;Goldberg;10180;Barth;10193;Ueckermünde;10210;Friesoythe-Altenoythe;10235;Soltau;10249;Boizenburg;10261;Seehausen;10267;Kyritz;10281;Trollenhagen;10282;Feldberg/Mecklenburg;10289;Grünow;10305;Lingen;10309;Ahaus;10312;Belm;) (Remarks from Volume-C: SYNOP)

GTS Bulletin: ISID05 EDZW - Observational data (Binary coded) - BUFR (details are described in the abstract)

The ISID05 TTAAii Data Designators decode as: T1 (I): Observational data (Binary coded) - BUFR T1T2 (IS): Surface/sea level T1T2A1 (ISI): Intermediate synoptic observations from fixed land stations A2 (D): 90°E - 0° northern hemisphere(The bulletin collects reports from stations: 10161;Boltenhagen;10168;Goldberg;10180;Barth;10193;Ueckermünde;10210;Friesoythe-Altenoythe;10235;Soltau;10249;Boizenburg;10261;Seehausen;10267;Kyritz;10281;Trollenhagen;10282;Feldberg/Mecklenburg;10289;Grünow;10305;Lingen;10309;Ahaus;10312;Belm;) (Remarks from Volume-C: SYNOP)

INSPIRE HH Bodenbedeckung ALKIS

Dieser Datensatz stellt die Bodenbedeckung der Freien und Hansestadt Hamburg aus dem Amtlichen Liegenschaftskatasterinformationssystem (ALKIS) im INSPIRE Zielmodell dar.

Schwerpunktprogramm (SPP) 1006: Bereich Infrastruktur - Internationales Kontinentales Bohrprogramm, Sub project: Bündel-Antrag Ohrid-See: Evolutionary, geological, and environmental history of Lake Ohrid (EGEL)

Lake Ohrid is a large (360 km2) and deep (289 m) lake of tectonic origin and is shared between the Republics of Macedonia and Albania. Biological and biogeographical studies of the lake revealed an outstanding degree of endemism and suggest a Pliocene origin of Lake Ohrid, making the lake the oldest one in Europe. The high age and the high degree of endemism make Lake Ohrid a first class site to investigate the link between geological and biological evolution in ancient lakes. Given its importance as refugium and spreading centre, the lake was declared a UNESCO world heritage site in 1979, and included as a target site of the International Continental Scientific Drilling Program (ICDP) already in 1993. The political situation in the Balkan in the mid 1990ies, however, hampered further establishment of Lake Ohrid as potential ICDP site. This proposal bundle seeks funds for the detection of the timing of major evolutionary events, the investigation of the origin, the sedimentological inventory, neotectonic movements, and the paleoecology and paleolimnology of Lake Ohrid in order to develop a full ICDP proposal for deep drilling. Within the scope of this cover proposal funds for the coordination of the single proposals, for scientific exchange between the single bundle proponents, and for the data management are applied for.

Erweiterung von Modellkonzepten für technisch kontrollierte Kalziumkarbonatausfällung unter besonderer Berücksichtigung mehrerer antreibender Prozesse, des Temperatureinflusses und der Zweiphasenströmung

Fluidspeicherung im Untergrund ist ein wichtiger Bestandteil der Bemühungen zur Eindämmung des Klimawandels (Speicherung von CO2) oder für Energiespeicherung um die Schwankungen durch die wechselnde, unvorhersehbare Produktion erneuerbarer Energierzeugung auszugleichen. Diese Fluide können jedoch durch undichte Brunnen oder beschädigte Deckschichten austreten. Die technisch kontrollierte Kalziumkarbonatausfällung ist von unseren Partnern an der Montana State University erfolgreich in Feldversuchen angewandt worden, solche Leckagen zu beheben. Die Anwendbarkeit einer bestimmten Methode von induzierter Kalziumkarbonatausfällung (ICP) wird hauptsächlich durch die Tiefe der Leckage und dem lokalen geothermalen Gradienten bestimmt. Mikrobiell induzierte Kalziumkarbonatausfällung (MICP) ist auf die Aktivität lebender bakterieller Zellen angewiesen, welche auf einen niedrigen Temperaturbereich beschränkt ist, der meist nur im flacheren Untergrund, in zur Speicherung von CH4 oder Erdgas geeigneten Tiefen gegeben ist, aber in geeigneten Reservoiren für die Speicherung von CO2 meist überschritten wird. Deswegen sollten weitere Möglichkeiten, Kalziumkarbonatausfällung durch Enzyme (EICP) oder thermische Prozesse (TICP) zu induzieren, entwickelt und in Feldversuchen erprobt werden. Das Hauptziel dieses Projekts ist es, das bestehende numerische Modell für MICP zu verallgemeinern um ein allgemeingültiges Modell zu erhalten, welches auch für EICP und TICP sowie Kombinationen der Prozesse verwendet werden kann. Dafür müssen zunächst alle für EICP und TICP relevanten Prozesse und deren Interaktionen identifiziert werden, um das Modellkonzepte zu formulieren. Für EICP und TICP sind nicht-isotherme Modelle besonders wichtig, da für beide die zentrale Harnstoffhydrolysereaktion stark temperaturabhängig ist. Dafür muss die temperaturabhängig der physikalischen Eigenschaften und der biogeochemischen Reaktionen sowie der Transport der inneren Energie quantifiziert und parameterisiert werden. Die Implementierung des Modells im Open-Source Simulator DuMuX (www.dumux.org) wird auf dem vorhandenen Modell für MICP aufbauen. Ein zweiter Teil des Projekts ist die Verbesserung des ICP Modells unter besonderer Berücksichtigung anwendungsrelevanter Prozesse, wie zum Beispiel der Auswirkung von ICP auf die Zweiphasenströmungseigenschaften. Diese Auswirkung ist bis jetzt noch nicht im bestehenden Modell berücksichtigt. Vor allem aufgrund der Anwendung von ICP zur Reduktion von Gasleckagen im Untergrund sollte das Modell die Auswirkung von ICP auf die Zweiphasenströmungseigenschaften jedoch berücksichtigen, da die Erhöhung des Eindringdrucks für das Gas auf Werte über den Reservoirdruck für eine ausreichende Abdichtung ausreicht.

Sickersaft- und Stickstoffaustrag waehrend der Rotte organischer Materialien unter besonderer Beruecksichtigung verschiedener Stalldung-Mietenabdeckungen

Es wurden Rinder- und Pferdemistmieten auf Sickersaftbildung und N-Austrag untersucht. Nur bei Rindermist wurden auch Versuche mit verschiedenen Abdeckungen durchgefuehrt. Sickersaftbildung und N-Austraege waren so gering, dass eine Gefaehrdung des Grundwassers ausgeschlossen werden kann. Die Sickersaftbildung insbesondere am Beginn der Rottezeit ist zu einem grossen Teil durch Atmungswasser bedingt. Niederschlaege hatten eine verhaeltnismaessig geringe Wirkung. Die Abdeckung hatte keinen besonders grossen Effekt. Sie bewirkt im Gegenteil eine staerkere Rotte aufgrund hoeherer Mietentemperaturen und damit staerkere Sickersaftbildung sowie hoehere Verluste an N und C.

Dynamics and stability of Wilkins and George VI ice shelves on the south-western Antarctic Peninsula

Mapping and monitoring the break-up events on Wilkins Ice Shelf and identification of mechanisms and processes leading to break-up. Within this activity we integrate various high and moderate-resolution satellite images with special emphasis on SAR data. The analysis covers currently a time period back to 1986 (Landsat TM) with increasing dense time series to present. In close collaboration with the European Space Agency (ESA) and the German Aerospace Center (DLR) acquisition plans for the ENVISAT ASAR and TerraSAR-X instruments are implemented and the respective data analysed. Since September 2009, this activity is supported by a DFG research grant. Main aim is to derive surface velocity fields of the ice shelf and its tributary glaciers by satellite remote sensing as input for icedynamic modelling and fracture mechanical analyses.

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