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

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.

Results of palynological analysis from 2020 of the varved MO-05 core from Lake Mondsee (Austria) section (249-526 cm)

This study reports a precisely dated pollen record with a 20-year resolution from the varved sediments of Lake Mondsee in the north-eastern European Alps (47°49′N, 13°24′E, 481 m above sea level). The analysed part of core spans the interval between 1500 BCE and 500 CE and allows changes in vegetation composition in relation to climatic changes and human activities in the catchment to be inferred. Intervals of distinct but modest human impact are identified at ca. 1450-1220, 740-490 and 340-190 BCE and from 80 BCE to 180 CE. While the first two intervals are synchronous with prominent salt mining phases during the Bronze Age and Early Iron Age at the nearby UNESCO World Heritage Site of Hallstatt, the last two intervals fall within the Late Iron Age and Roman Imperial Era, respectively. Comparison with published records of extreme runoff events obtained from the same sediment core shows that human activities (including agriculture and logging) around Lake Mondsee were low during intervals of high flood frequency as indicated by a higher number of intercalated detrital event layers, but intensified during hydrologically stable intervals. Comparison of the pollen percentages of arboreal taxa with the stable oxygen isotope and potassium ion records of the NGRIP and GISP2 ice cores from Greenland reveals significant positive correlations for Fagus and negative correlations for Betula and Alnus. This underlines the sensitivity of vegetation around Lake Mondsee to temperature fluctuations in the North Atlantic as well as to moisture fluctuations controlled by changes in the intensity of the Siberian High and the North Atlantic Oscillation (NAO) regime.

ISLAS2022: Calibrated stable water isotope measurements and aerosol measurements around the Nordic Seas

During a 4-week measurement campaign (ISLAS2022) in March and April 2022, we collected a comprehensive dataset characterizing the atmospheric water vapour and precipitation isotope composition within weather systems in the European Arctic and sub-Arctic. Focusing on an area covering the Nordic Seas and Northern Scandinavia, stable water isotope measurements with cavity ring-down spectrometers (CRDS) were taken from a research aircraft stationed at Kiruna, Sweden; from a Research Vessel going from Tromsø to the western ice edge in Greenland, and from measurements at supersites at Andenes on the Lofoten archipelago, Abisko, and Kiruna. Water vapour and precipitation isotope measurements from different sites and platforms were complemented by additional instrumentation to characterize the atmospheric conditions. Advanced instrumentation included wind LIDAR, ground-based vertical-pointing rain radar, and aerosol measurements at Andenes, two-directional depolarising aerosol LIDAR and horizontal cloud RADAR on the aircraft. Controlled meteorological balloons were launched from Ny-Ålesund, Svalbard into cold-air outbreak conditions. Surface precipitation samples were collected from a surface network including Abisko, Andenes, Kiruna, Longyearbyen, Ny-Ålesund, Jan Mayen, Bjørnøya, Tarfala, Ålesund, and Bergen. Surface snow was repeatedly sampled along a detailed transect from Kiruna to Lofoten archipelago. Citizen science snow sampling contributed to distributed surface snow sampling in Northern Scandinavia. All stable water isotope measurements have been calibrated onto the VSMOW-SLAP scale. The data from the ISLAS2022 measurement campaign enables the comprehensive assessment of air mass transformation and water turnover during cold-air outbreak conditions using stable water isotopes as a constraint.

Interoperabler INSPIRE View-Service: Agricultural And Aquaculture Facilities / Tierhaltungsanlagen nach BImSchG in Brandenburg - Interoperabler INSPIRE View-Service (WMS-AF-TIERE)

Der interoprable INSPIRE-Viewdienst (WMS) Agricultural and Aquaculture Facilities gibt einen Überblick über die Tierhaltungs- und Aufzuchtanlagen im Land Brandenburg. Der Datensatz umfasst Geflügel, Rinder, Kälber, Schweine und gemischte Bestände. Die Datenquelle ist das Anlageninformationssystem LIS-A. Gemäß der INSPIRE-Datenspezifikation Agricultural and Aquaculture Facilities (D2.8.III.9_v3.0) liegen die Inhalte INSPIRE-konform vor. Der WMS beinhaltet 2 Layer: AgriculturalHolding und Sites. Der Holding-Layer wird gem. INSPIRE-Vorgaben nach Wirstschaftszweigen (NACE-Kategorie "A") untergliedert in: - AF.GrowingOfPerennialCrops: Anbau mehrjähriger Pflanzen (NACE-Kategorie "A.01.2") - AF.AnimalProduction: Tierhaltung (NACE-Kategorie "A.01.4") - AF.MixedFarming: Gemischte Landwirtschaft (NACE-Kategorie "A.01.5")

Agricultural And Aquaculture Facilities / Tierhaltungs- und Aufzuchtanlagen in Brandenburg

Der Datensatz Agricultural And Aquaculture Facilities / Tierhaltungs- und Aufzuchtanlagen in Brandenburg ist die Datengrundlage der interoperablen INSPIRE-Darstellungs- (WMS) und Downloaddienste (WFS): Tierhaltungsanlagen nach BImSchG in Brandenburg - Interoperabler INSPIRE View-Service (WMS-AF-TIERE) Tierhaltungsanlagen nach BImSchG in Brandenburg - Interoperabler INSPIRE Download-Service (WFS-AF-TIERE) Der Datenbestand beinhaltet die Punktdaten zu den betriebenen Tierhaltungsanlagen aus dem Anlageninformationssystem LIS-A. Die Angaben zu den Anlagen enthalten jeweils den Standort und die genehmigte Leistung. Dabei erfolgte eine sog. Schematransformation und Belegung der INSPIRE-relevanten Attribute. Der Datensatz Agricultural And Aquaculture Facilities / Tierhaltungs- und Aufzuchtanlagen in Brandenburg ist die Datengrundlage der interoperablen INSPIRE-Darstellungs- (WMS) und Downloaddienste (WFS): Tierhaltungsanlagen nach BImSchG in Brandenburg - Interoperabler INSPIRE View-Service (WMS-AF-TIERE) Tierhaltungsanlagen nach BImSchG in Brandenburg - Interoperabler INSPIRE Download-Service (WFS-AF-TIERE) Der Datenbestand beinhaltet die Punktdaten zu den betriebenen Tierhaltungsanlagen aus dem Anlageninformationssystem LIS-A. Die Angaben zu den Anlagen enthalten jeweils den Standort und die genehmigte Leistung. Dabei erfolgte eine sog. Schematransformation und Belegung der INSPIRE-relevanten Attribute.

Water isotope values in shore samples collected in March and July 2020 from northeastern German lake systems

Water isotopes (δ2H and δ18O) were analyzed in samples collected in lakes associated to major riverine systems in northeastern Germany throughout 2020. This sub-dataset is derived from water samples collected from lake shores. Samples were taken in March and July 2020 with a pipette from 40-60 cm depth below water surface and directly transferred into a measurement vial. Stable isotope analysis was conducted at IGB Berlin, using a Picarro L2130-i cavity ring-down spectrometer. The data give information about the seasonal isotope amplitude in the sampled lakes and about spatial isotope variability in different branches of the associated riverine systems.

Stable Water Isotopologue data collected during HCCT-2010

Cloud samples for the isotopic analysis were collected in the framework of the Hill Cap Cloud Thuringia 2010 (HCCT-2010) campaign on Schmücke (50° 39'N/ 10° 46'E, 937 m a.s.l.; Germany) in September and October 2010 with a three-stage Caltech Active Strand Cloudwater Collector (CASCC) during 13 different cloud events with a temporal resolution of 1 to 3 hours. In a first step, we ensured that no additional fractionation occurred during sampling with the CASCC. The d values of the three sizes classes of the CASCC (4 µm to 16 µm, 16 µm to 22 µm and >22 µm) did not differ significantly, revealing that the cloud droplets of different sizes quickly equilibrate their delta value with the one of the surrounding vapor. delta values in the cloud droplets varied from -77 per mil to -15 per mil in d2H and from -12.1 per mil to -3.9 per mil in d18O and were fitted by d2H =7.8*d18O +13*10**-3. delta values decreased with temperature as well as towards the end of the campaign, representing a seasonal trend which is known from d values in precipitation. The deuterium excess of the cloud samples was generally higher than the Local Meteoric Water Line of the closest GNIP (Global Network of Isotopes in Precipitation) station. Rain decreases its deuterium excess during falling through an unsaturated air column, while the cloud droplets conserve the deuterium excess of the initial evaporation and thus have been found to be a good indicator for the airmass source region: higher deuterium excess was measured for polar air masses and lower deuterium excess for Mediterranean air masses. Changes in d values during one cloud event were up to 3.6 per mil (d2H) and 0.23 per mil (d18O), except for frontal passages, which were associated with increases of ~6 per mil per hour (d2H) and ~0.6 per mil per hour (d18O). Using a box model, we showed that the influence of condensation only was able to explain the variation in the isotope signal of two cloud passages. Consequently, we deduced that the water vapor "feeding" the cloud advected the measured changes. A trajectory analysis and moisture source diagnostic revealed that it is very likely that the variations were either related to rain out along the trajectories or to meteorological changes in the moisture source region. This was the first study using stable water isotopologues in cloud water manifesting their potential in the context of atmospheric water vapor circulation.

Seasonal Dataset of DIC, δ13CDIC, DOC, δ13CDOC, pCO2(aq), FCO2 and Biogeochemical Parameters in the Danube River (2023–2024)

This dataset contains dissolved inorganic/organic carbon (DIC/DOC) concentrations, its stable isotope ratios (δ13CDIC/DOC), partial pressure of carbon dioxide in the water column pCO₂(aq) (pCO2(aq)) and area-integrated CO₂ emission rates derived from flux calculations (FCO2; g C d⁻¹), along with corresponding parameters (temperature, pH, calcium, bicarbonate) collected from the Danube River and its key tributaries during five seasonal sampling campaigns in 2023 and 2024. Water samples were collected using a weighted 2 L sampling bottle submerged 1–2 meters below the surface, with sampling conducted from the river center via bridges or passenger boats, and occasionally from the riverbank. In situ temperature measurements were taken with a multiparameter instrument (HQ40d, HACH™, Loveland, CO, USA). δ13ODIC/DOC was analyzed using a OI Analytical Aurora 1030W-IRMS. This dataset is providing valuable insights into carbon dynamics in a large river system and support investigations of biogeochemical cycling. It further can inform ecosystem management and conservation strategies under changing environmental conditions.

Diel carbon chemistry, stable carbon and oxygen isotopes, calculated pCO2 and CO2 fluxes during a 24 h survey in the Wiesent karst headwater, northern Bavaria, Germany (August 2023)

This dataset contains diel measurements of alkalinity, dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), particulate organic carbon (POC), d18O values of dissolved oxygen, and calculated partial pressure of CO2 (pCO2), calculated CO2 fluxes, and calculated gas-transfer velocity (k600) from stream-water samples collected at three sites along the Wiesent karst headwater stream in northern Bavaria, Germany, between 21 and 22 August 2023. Measurements were conducted at 4 h intervals over a 24 h period to assess short-term variability in carbon and oxygen cycling and CO2 evasion.

Carbon concentrations, stable carbon isotopes, calculated pCO2 and CO2 fluxes from the White Main headwater stream, Germany, 2023–2024

This dataset contains laboratory-measured alkalinity, dissolved inorganic and organic carbon concentrations, δ13C values of DIC and DOC, and calculated pCO2, CO2 fluxes, and k600 from stream water samples collected along the White Main headwater stream in northern Bavaria, Germany, from March 2023 to April 2024.

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