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Timeseries of binned benthic stable carbon isotope from ODP Site 162-982,130-807 and ODP Site 162-982

This dataset contains C. wuellerstorfi stable carbon isotope values binned by marine isotope stage from ODP Site 162-807 and ODP Site 162-982 that span the last 4.5 million years (Feng et al. 2022; Venz et al. 1999, 2002; Hodell & Venz-Curtis 2006). This isotope gradient reflects the accumulation of respired and disequilibrium carbon in the deep Pacific ocean relative to the North Atlantic. Also included are binned probstack δ18O (Ahn et al., 2017) and ΔGMST (Clark et al., 2024) values for comparison to the binned stable carbon isotope values.

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.

Hexavalent chromium (Cr(VI)) removal by reduction-coagulation-filtration (RCF) combined with deacidification in drinking water treatment

Excess dissolved carbon dioxide (CO2) is frequently encountered in natural groundwaters, originating from both geochemical and biological processes. In the investigated case, contamination of groundwater with toxic hexavalent chromium (Cr(VI)) occurred due to anthropogenic activities. The co-occurrence of CO2 and Cr(VI) posed a distinct challenge for water treatment, as multiple process steps need to be tailored to remove both substances at the same time. This study investigates an integrated treatment approach specifically developed for groundwater containing elevated levels of both Cr(VI) and CO2. The process combines reduction coagulation filtration (RCF) with ferrous iron (Fe(II)) dosage with limestone filtration for concurrent Cr(VI) removal and water deacidification. A pilot plant with two parallel filters—one filled with dense limestone and the other with porous limestone—was operated under varying Fe(II) dosages (Fe(II), 0.3–1.0 mg/L) and filtration velocities (4.4–15.5 m/h). Results demonstrate that the RCF process achieved efficient Cr(VI) removal at moderate Fe(II) concentrations (<1.0 mg/L), with no breakthrough or reoxidation observed. Limestone filtration efficiently increased pH, calcium concentration, and buffer capacity, thereby decarbonating the water. Porous limestone showed higher reactivity than the dense limestone commonly used. Analysis of backwash sludge confirmed stable chromium retention and low residual metal concentrations in the supernatant. These findings confirm that the integrated RCF–limestone process provides an effective and cost-efficient solution for treating groundwater impacted by anthropogenic Cr(VI) and naturally elevated CO2 concentration. © 2026 The Authors.

Hydrochemistry, carbon dynamics, and calculated pCO2 and CO2 fluxes, and soil-derived natural organic matter characteristics from the White Main, a granitic headwater stream in Germany, 2023-2024

This dataset contains hydrochemical and soil data collected along the first 1.3 km downstream of the White Main spring in northern Bavaria, Germany, from March 2023 to November 2024. Stream water samples were analyzed for in situ parameters, including discharge, water temperature [°C], pH [-], redox potential [mV], and electrical conductivity [µS/cm], as well as laboratory-measured parameters, including major ions and trace metals [mmol/l], alkalinity [mmol/l], dissolved inorganic and organic carbon concentrations (DIC, DOC [mmol/l]), and their stable isotope ratios (δ13CDIC/DOC [‰ VPDB]). In addition, calculated partial pressure of CO2 (pCO2 [µatm]) and carbon dioxide fluxes (FCO2 [mmol m⁻² d⁻¹]) are provided for the stream water samples. The dataset also contains laboratory measurements related to soil-derived natural organic matter from acid and base extracts of soil samples, including zeta potential [mV], particle size distribution [%], ultraviolet-visible absorbance (UV-VIS), and fluorescence measurements. UV-VIS absorbance and fluorescence measurements were additionally performed on stream water samples. The datasets were collected to characterize hydrochemistry, carbon concentrations, carbon dioxide dynamics, and soil-derived organic matter properties in a granitic headwater stream and to provide a basis for reuse in studies of headwater biogeochemistry, carbon cycling, and soil-water interactions.

Social TrAnsformation of the BuiLding sEctor: Sozialgerechte Transformation des Mehrfamilienhausbestands hin zur Klimaneutralität mit Reallaborcharakter

Im Rahmen des Projekts STABLE soll die Sanierung eines Mehrfamilienhauses (MFH) wissenschaftlich begleitet werden, wobei eine sozialgerechte Klimaneutralität oberste Prämisse ist. Das Projektkonsortium bringt die notwendigen Expert:innen aus Wissenschaft und Praxis an einen Tisch und schafft somit einen Verfahrensrahmen für die gesellschaftlich akzeptierte Energiewende im Gebäudebereich. Die Untersuchung aller relevanten Akteur:innen stellt sicher, dass die Transformation im Sinne der Gesellschaft stattfindet, was den langfristigen Erfolg des Konzepts sichert. Das Projekt umfasst sowohl die Konzeptionierung eines klimaneutralen Energiesystems für ein existierendes MFH als auch dessen Umsetzung und nachträgliche Begleitung. Damit ermöglicht das Projekt die ganzheitliche Untersuchung des Energiesystems auf der einen Seite und der relevanten Akteur:innen auf der anderen Seite. Für relevante Akteur:innen werden partizipative Methodiken angewandt, um die Energiewende für alle erlebbar zu machen, Bewohner:innen einzubinden und Interessenskonflikte sichtbar zu machen. Die Begleitung der Umsetzung garantiert, dass die zur sozialverträglichen Transformation des Gebäudebestandes existierenden Hürden erkannt sowie Lösungsstrategien entwickelt werden. Zudem wird durch den Dialog mit allen relevanten Akteur:innen angestrebt, dass ein Drehbuch die Erfahrungen aus den Beteiligungsprozessen und innovativen Partizipationsformaten für Sanierungsprojekte anderer Gebäudetypen übertragbar macht.

KMU-innovativ - AkuMonit: Intelligentes akustisches Monitoringsystem für Tierhaltungsanlagen zur ökologischen und ökonomischen Optimierung

RUBIN - PhoTech - VP3 biogene & industrielle Luft, TP3.2: Photonischer Abbau biogener und industrieller Schadstoffe mittels Photokatalyse

Brackish water rewetting of a temperate coastal peatland in NE Germany: Effects on Biogeochemistry, Microorganisms and Greenhouse gas emissions

The rewetting of drained peatlands is a promising measure to mitigate carbon dioxide (CO2) emissions by preventing the further mineralization of the peat soil through aeration. While freshwater rewetted peatlands can be significant methane (CH4) sources in the short-term, in coastal ecosystems the input of sulfate-rich seawater could potentially mitigate these emissions. The purpose of the data collection was to examine whether the presence of sulfate, known as an alternative electron acceptor, can cause lower CH4 production and thus, emissions by favoring the growth of sulfate-reducers, which outcompete methanogens for substrate. We therefore investigated underlying variables such as the methane-cycling microbial community along with CH4 fluxes and set them in context with CO2 fluxes along a transect in a coastal peatland before and directly after rewetting. In this way, a conclusion about the short-term greenhouse gas mitigation potential of brackish water rewetting of coastal peatlands could be drawn. This data collection consists of six data sets, with direct comparisons before and after rewetting of CO2 and CH4 fluxes (Tab. 2) and associated microbial communities (Tab. 1) being the main data. Pore water geochemistry (Tab. 1 and 3) and surface water parameters (Tab. 4) were collected simultaneously to provide potential explanatory variables. The sampling of continuous water level (Tab. 5) within wells and atmospheric weather data (air and soil temperature, relative humidity, photosynthetic photon flux density; Tab. 6) from a weather station was done in addition. Measurements started in June/July/August 2019 after field installation was finalized and were conducted on the drained coastal fen "Polder Drammendorf" on the island of Rügen in North-East Germany. On 26th November 2019, the dike was opened and channeled in order to rewet the peatland with brackish water. Before, the dike separated the peatland from the adjacent bay "Kubitzer Bodden", which is part of a brackish lagoon system connected to the Baltic Sea. Therefore, the peatland was nearly completely flooded and now resembles a shallow lagoon with high fluctuating water levels. We measured along a humidity (pre-rewetting)/water level (post-rewetting) gradient (stations 0-8) towards and across the main North-South oriented drainage ditch, including four stations on the Eastern side of the ditch (1–4), two ditch stations (0, 5) and two stations (6, 7) on the Western side of the ditch. Station 8 was chosen as an additional station farther towards the adjacent bay on the Western side, but was only accessible before rewetting. CH4 and CO2 fluxes (stations 0-7) were calculated from online gas concentrations measurements using laser-based analyzers and manual closed chambers (Livingston, G. P., & Hutchinson, G. (1995). Enclosure-based measurement of trace gas exchange: Applications and sources of error. In P.A. Matson, & R.C. Harriss (Eds.). Biogenic trace gases: Measuring emissions from soil and water (pp. 14–51). Blackwell Science Ltd., Oxford, UK). Soil cores for microbial, dissolved gas concentrations and isotopic analysis were taken using a Russian type peat corer (De Vleeschouwer, F., Chambers, F. M., & Swindles, G. T. (2010). Coring and sub-sampling of peatlands for palaeoenvironmental research. Mires and Peat, 7, 1–10) before and after rewetting. Each time, we took duplicates at stations 1-8 for this rather labor-intensive process and divided the core into four depth sections: surface, 5–20, 20–40 and 40–50 cm. Subsamples for dissolved gases and stable carbon isotope analyses were taken with tip-cut syringes with a distinct volume of 3 ml (Omnifix, Braun, Bad Arolsen, Germany) and immediately placed into NaCl-saturated vials (20 ml, Agilent Technologies, 5182-0837, Santa Clara, USA) leaving no headspace and closed gas-tight using rubber stoppers and metal crimpers (both: diameter 20 mm, Glasgerätebau Ochs, Bovenden, Germany). Absolute abundances of specific functional target genes, including methane- and sulfate-cycling microorganisms, were measured with quantitative PCR (qPCR) after DNA was extracted (GeneMATRIX Soil DNA Purification Kit, Roboklon, Berlin, Germany) and quantified (Qubit 2.0 Fluorometer, ThermoFisher Scientific, Darmstadt, Germany). Surface and pore water parameters were measured in parallel to the gas measurements and soil coring for microbial analyses. Most surface water variables (pH, specific conductivity, salinity, nutrients, oxygen, sulfate and chloride concentrations, DOC/DIC) were measured in-situ using a multiparameter digital water quality meter or taken to the laboratory as water samples for further analysis. Likewise, pore water/soil variables (pH, specific conductivity, nutrients, metals, sulfate and chloride concentrations, CNS) were either measured in-situ or taken to the laboratory as soil samples. While surface water analysis was only conducted in the drainage ditch before rewetting, it was done along the entire transect after rewetting. In contrast, pore water/soil analysis was mostly conducted before rewetting and only repeated occasionally after rewetting where possible.

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.

Pond/ditch benthic invertebrate data on d15N/d13C (northeast-Germany, 2020)

Benthic invertebrate samples were taken directly in the field via hand-netting in four ditches and three ponds (defined as water bodies with a maximum extent of one hectare) in October and November 2020. Sampling was carried out in Brandenburg in Germany in the region Havellaendisches Luch. The landscape is characterized by an intensively maintained ditch system that was created for industrial agricultural production during 1980s. Additionally, the landscape is characterized by a large number of small standing water bodies (kettle holes, ponds), which were formed during the last glacial period. A detailed description of the area can be found in Trau & Lorenz, 2024. Invertebrate samples were analysed for the stable isotopes of carbon and nitrogen. The data set includes data from 35 families. The whole animal was used for the analysis of stable isotopes of carbon and nitrogen. Analyses were performed on a Thermo Delta V isotope ratio mass spectrometer (IRMS) interfaced to a NC2500 elemental analyser by the Cornell University Stable Isotope Laboratory (https://cobsil.cornell.edu/). The dataset was used to evaluate isotopic niches of functional feeding groups (collector/gatherer, collector/filterer, grazer/scraper, shredder, predator and omnivore) in the two water body types (pond and ditch), in order to evaluate effects of agriculture (nutrient concentrations and pesticide residues) on the isotopic niches (Trau et al. 2025, under review).

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