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Pore-water pH, H2S, Cl-, SO42-, SiO2, NO2-, PO43-, NH4+, NO3-, major and trace element data from MUC cores taken during RV HEINCKE cruises HE575 and HE595 in the Helgoland Mud Area, German Bight

This dataset includes downcore measurements of pH values, H2S, Cl-, SO42-, SiO2, NO2-, PO43-, NH4+, NO3-, As, Ba, Ca, Cu, Fe, K, Li, Mg, Mn, Mo, P, Si and Sr concentrations for sediment cores retrieved using multi-corer sampling during RV Heincke expeditions HE575 and HE595 in 2021 and 2022, respectively. The samples were collected in the framework of the Project APOC (Anthropogenic impacts on particulate organic carbon cycling in the North Sea). All measurements were performed in the laboratories of the Alfred Wegener Institute (AWI) in Bremerhaven, Germany, except pH values, which were determined onboard the research vessel.

Analytical data of floodplain, colluvial, Triassic (Buntsandstein), Lopingian (Zechstein) and Pleistocene loess data from the Weiße Elster catchment (Central Germany)

In this dataset, we present grain size and XRF element data of Holocene floodplain and colluvial, Pleistocene loess and Triassic (Buntsandstein) samples from the catchment of the Weiße Elster River (Central Germany). The samples were taken during the DFG-funded project 'Imprints of rapid climate changes and human activity on Holocene hydro-sedimentary dynamics in Central Europe (loess-covered Weiße Elster model region)' [SU491/6-1, ET20/10-1, VE117/7-1, WE5518/1-1, ZI721/13-1] between 2017 - 2025, using open outcrops, hand augering (Pürckhauer) or drilling with an Atlas Copco Cobra Pro hammer. The goal of this study was to obtain sediment provenance for Holocene overbank sediments in the middle Weiße Elster floodplain.

Strontium-Hintergrundwerte im Grundwasser von Niedersachsen 1 : 500.000

Die natürliche Grundwasserbeschaffenheit ist maßgeblich durch die Wechselwirkung zwischen Grundwasser und der durchströmten Gesteinsmatrix geprägt. In Deutschland sind die Grundwässer jedoch durch anthropogene Handlungen wie z.B. Ackerbau, Rodung und Maßnahmen zur Grundwasserentnahme ubiquitär überprägt. Einflüsse einer Jahrhunderte alten Kulturlandschaft können dennoch als natürlich betrachtet werden (Funkel et al. 2004). Zur Erfüllung der Aufgaben aus der EG-Wasserrahmenrichtlinie (EG-WRRL) wurden für die hydrogeologischen Teilräume Niedersachsens (Elbracht et al., 2016) Hintergrundwerte u.a. für gelöstes Strontium im Grundwasser ermittelt. Die Hintergrundwerte von gelöstem Strontium umfassen die Gehalte, welche sich unter natürlichen Bedingungen durch den Kontakt des Grundwassers mit der umgebenden Gesteinsmatrix des Grundwasserleiters sowie in Kontakt mit einer Jahrhunderte alten Kulturlandschaft einstellen. Die Karte zeigt farblich differenziert Klassen der Strontium-Hintergrundwerte der hydrogeologischen Teilräume Niedersachsens. Durch das Auswählen eines Teilraumes gelangt man zu weiterführenden Informationen (z.B. Probenanzahl, zusammengefasste Teilräume, etc.). Informationen zu den Daten: Die genutzten Grundwasseranalysen stammen aus der Datenbank des Niedersächsischen Bodeninformationssystems (NIBIS). Hintergrundwerte sind definiert als das 90.-Perzentil der Normalpopulation der geogenen Konzentration des analysierten Parameters. Zur Bestimmung der Hintergrundwerte wurde die jeweils aktuellste Analyse einer Grundwassermessstelle verwendet. Bei zu geringer Probenzahl (n < 10) wurden, soweit möglich, lithologisch ähnliche Teilräume zu einem gemeinsamen Hintergrundwert zusammengefasst. Die Ermittlung der Hintergrundwerte folgte dem Verfahren zur statistischen Auswertung der Daten mittels Wahrscheinlichkeitsnetz der Staatlichen Geologischen Dienste (Wagner et al., 2011). Quellen: ELBRACHT, J., MEYER, R. & REUTTER, E. (2016): Hydrogeologische Räume und Teilräume in Niedersachsen. – GeoBerichte 3, LBEG, Hannover. DOI: 10.48476/geober_3_2016. Funkel R., Voigt H.-J., Wendland F., Hannappel S. (2004): Die natürliche ubiquitär überprägte Grundwasserbeschaffenheit in Deutschland, Forschungszentrum Jülich GmbH (47), ISBN: 3-89336-353-X. WAGNER, B., WALTER, T., HIMMELSBACH, T., CLOS, P., BEER, A., BUDZIAK, D., DREHER, T., FRITSCHE, H.-G., HÜBSCHMANN, M., MARCZINEK, S., PETERS, A., POESER, H., SCHUSTER, H., STEINEL, A., WAGNER, F. & WIRSING, G. (2011): Hydrogeochemische Hintergrundwerte der Grundwässer Deutschlands als Web Map Service. – Grundwasser 16(3): 155-162; Springer, Berlin / Heidelberg.

Prüfung und Begutachtung der Umweltverträglichkeit des AVR-Zwischenlagers für sonstige radioaktive Stoffe

Das Öko-Institut führt im Auftrag der Bezirksregierung Köln die Prüfung und Begutachtung der Umweltverträglichkeit des AVR-Zwischenlagers für sonstige radioaktive Stoffe durch. Das AVR-Zwischenlager wird auf dem Gelände des Forschungszentrums Jülich errichtet. Darin soll der Reaktorbehälter des AVR-Forschungsreaktors über mehrere Jahrzehnte zum Abklingen gelagert werden. Der eigentliche Standort des AVR-Reaktorbehälters wird unterdessen zurückgebaut, wobei Sanierungsbedarf für den Boden durch vorhandene Strontium-90-Kontaminationen besteht. Auch dieses Projekt - Rückbau des AVR-Forschungsreaktors - betreut das Öko-Institut derzeit durch Begutachtung der Umweltverträglichkeit.

Geochemical signature of last glacial maximum European loess samples

In a previous analysis of bulk sediment from Last Glacial Maximum loess deposits over Europe, a local to regional origin of the deposited material has been demonstrated (Rousseau et al., 2014). In a refined study, the same European sequences have been analyzed studying the trace elements and the strontium and lead isotopic ratios from different grain-size fractions: <2 micron, 2-20 micron and bulk. The later was reanalyzed to compare with the previous study. First the new bulk values are similar to the previously published ones. Furthermore, the results show that the <2 micron fraction is different than the 2-20 micron or bulk ones when comparing the trace element. Second, the 87Sr/86Sr vs 208Pb/204Pb diagram shows that the sequences analyzed keep their regional to local signature, mainly along the 87Sr/86Sr axis for the 2-20 micron and bulk samples. On the contrary, the <2 micron samples are all grouped in a well identified cluster clearly indicating a different source and even a different transport. The comparison of the results of the geochemical analysis with climate modeling of dust transport at LGM supports this interpretation. The datasets correspond to i) the code and geographical coordinates, ii) the trace element contents for the <2 micron, 2-20 micron and bulk fractions, iii) the Sr-Pb isotopic ratios for the <2 micron, 2-20 micron and bulk fractions, and iv) the grain size composition of the studied LGM European loess samples.

Submarine groundwater discharge in front of a coastal peatland: Seepage rates and hydrochemistry

Coastal peatlands are important carbon, nutrient, and trace metal stores, which might be mobilized and released to the adjacent sea upon rewetting. The objectives of this study were to quantify submarine groundwater discharge (SGD) in front of a rewetted coastal peatland at the southern Baltic Sea coast, to estimate associated fluxes of solutes, and to characterize the discharged water using stable oxygen, hydrogen, and carbon isotope composition. We directly measured SGD rates and collected the discharging water using seepage meters in summer and autumn 2021. SGD, seawater and groundwater were analyzed for major ion, nutrient, DOC/DIC and trace metal concentrations as well as the composition of water and carbon isotopes. Racasa et al. (2026) is based on this dataset.

Iron, mercury and tin contents as well as grain sizes measurements from fluvial sediments of the Röslau River, Bavaria, Germany

We measured Sn, Fe and Hg content as well as grain size composition of soil cores and streambed samples from the floodplain of the Röslau River (Bavaria, Germany), in order to reconstruct the floodplain development and chemical antropogenic impacts. The samples were collected in 2023 and analysed in 2023/24 using aqua regia digestion and ICP-OES/ICP-MS to analyse the elemental composition. To prepare the samples, the sediment was sieved (2 mm) to discard the gravel fraction and large organic pieces. Further homogenisation was undertaken by grinding the samples with a vibratory mill. Grain sizes were obtained using a combination of sieving and laser diffraction (Microtrac particle analyser; Microtrac Retsch GmbH SYNC SN 0233).

Elbe Element Explorer 2018-2023: A time series of dissolved metals in the Elbe river

The river Elbe flows through Geesthacht right before the tidal part of the Elbe begins. In order to monitor and investigate the metal load and transport from the upstream river with a study focus on extreme events, water samples were taken weekly from the Geesthacht riverbank a couple of kilometers upstream of the weir starting in April 2018 and going until April 2023. During extreme events, i.e. floods or droughts, the sampling interval was increased to (bi-)daily sampling. The water samples were taken in pre-cleaned LDPE bottles, filtered over <0.45 µm polycarbonate filters into pre-cleaned LDPE bottles/tubes and acidified with nitric acid. The filtrates were then measured for their (trace) metal concentrations with ICP-MS/MS coupled online to a seaFAST preconcentration and matrix removal system. The physiochemical parameters pH value, dissolved oxygen, temperature and conductivity were measured for each sample using a corresponding multimeter probe.

Pore water data of sediment incubation experiments under anoxic conditions

Enhanced mineral dissolution in the benthic environment is currently discussed as a potential technique for ocean alkalinity enhancement (OAE) to reduce atmospheric carbon dioxide (CO2) levels. This study explores how biogeochemical processes affect the dissolution of alkaline minerals in surface sediments during laboratory incubation experiments. These involved introducing dunite and calcite to organic-rich sediments from the Baltic Sea under controlled conditions in an anoxic to hypoxic environment. The sediment cores were incubated with Baltic Sea bottom water. Eight sediment cores were positioned vertically in a rack. Since the sediment surface was slightly oxidized by the bottom water (∼125 μmol l−1 upon recovery), the cores were left plugged on the top for 13 days to settle after recovery until the sediment surface was anoxic. To achieve chemical conditions that are expected in the natural system, 500l of retrieved sea water were degassed via bubbling with pure dinitrogen gas in batches of 100 l. Afterwards, between 50 and 60 l were transferred into an evacuated gas tight bag. After the transfer, pH and total alkalinity (TA) were measured to determine the dissolved inorganic carbon (DIC) of the water. Afterwards the DIC was increased via adding pure CO2 until a CO2 partial pressure (pCO2 ) of ∼2,300–∼3,300 μatm was established mimicking conditions prevailing in Boknis Eck during summer. Stirring heads were installed on the cores. To prevent the development of oxic conditions, it was ensured that as little gas phase as possible was left in the cores. Elimination of pelagic autotrophs, heterotrophs, and suspended particles was achieved by flushing the cores with modified bottom water for 2 days with a flow rate of 1.5 mml min−1. Afterwards, a continuous throughflow of 700 μl min−1 from the reservoir of modified bottom water was applied, leading to a residence time of ∼2.1 days inside the cores. For the experimental incubations, six cores received additions of alkaline materials, three with calcite (Cal1 - Cal3) and three cores with dunite (Dun1 - Dun3), leading to three replicates per treatment. Two control cores remained untreated (C1, C2). The amount of added substrate was based on the rain rate of particulate organic carbon observed in Boknis Eck (0.5 mmol cm−2 a−). The incubation lasted for 25 days. The volume of water in each core was determined at the end of the experiment via measuring the height of the water column after removing the stirring heads. At the end of the experiments, the bottom water was removed via suction and the cores were sliced for pore water analysis. The pore waters were recovered by centrifuging each respective sediment layer in 50 ml falcon tubes at 3000 rpm for 10 minutes. Afterwards, the supernatant water was transferred to polyethylene (PE) vials in an Ar-filled glove bag to minimize contact with oxygen. All samples were filtered through a 0.2 µm cellulose membrane filter and refrigerated in 25 ml ZinsserTM scintillation vials. TA samples (1 ml) were titrated with 0.02N HCl. For H2S, an aliquot of pore water was diluted. A 5 ml aliquot was frozen directly after the sampling procedure for later nutrient analysis. Nutrient measurements were performed either via manual photometric measurement (NH4) or using a Seal – AnalyticalTM QuAAtro autoanalyzer (PO43-). Samples for TA were analyzed directly after sampling by titration of 1 ml of bottom/pore water with 0.02N HCl. Titration was ended when a stable purple color appeared. During titration, the sample was degassed by continuous bubbling with nitrogen to remove any generated CO2 and H2S. The acid was standardized using an IAPSO seawater standard. Acidified sub-samples (30 μl suprapure HNO3- + 3 ml sample) were prepared for analyses of major and trace elements (Si, Na, K, Li, B, Mg, Ca, Sr, Mn, Ni and Fe) by inductively coupled plasma optical emission spectroscopy (ICP-OES, Varian 720-ES). For H2S, an aliquot of pore water was diluted with appropriate amounts of oxygen-free artificial seawater and the H2S was fixed by immediate addition of zinc acetate gelatin solution

Geochemical composition of S1 sediment core from Lower Odra Valley, NW Poland

Oxbow lakes are continuous archives of flood events. On 28th June 2022 a 7.5 m long bottom sediment core (S1: 53.24758°N and 14.46271°E, 2.4 m b.s.l.) was collected from an oxbow lake in the Lower Odra Valley, NW Poland. Drilling was conducted using an Instorf sampler (Russian type; chamber dimension: 10 x 50 cm), onboard a "Manat" catamaran motorboat. After core recovery, each half-metre section was packed into a PVC tube and kept in cool rooms with a constant temperature. Samples were collected every 4 cm. For the first 2 m of the core grain-size, geochemical and Chironomidae analyses as well as radiocarbon dating were performed, which allow to identify flood events in the last 3200 years.

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