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Herkunft von Schelfwasser und Pazifischem Wasser in der arktischen Salzgehaltsschichtung abgeleitet von stabilen Sauerstoffisotopen

Ziel des Projektes ist eine Bestandsaufnahme der Wassermassenverteilung und der Zirkulation im Arktischen Ozean. Stabile Sauerstoffisotopen (delta18O) des Wassers ist ein konservativer Tracer und werden zusammen mit hydrochemischen Daten dazu verwendet das vom Schelf stammende Süßwasser (Flusswasser und Meereis-Schmelze oder Bildung) und die aus dem Pazifik stammende Komponente zu untersuchen. Auf diese Weise wird der Einfluss dieser Wassermassen in der arktischen Salzgehaltsschichtung (Halokline), dem Atlantischen Zwischenwasser und dem Tiefen- und Bodenwasser des Arktischen Ozeans quantifiziert werden. Es ist bekannt, dass die Verteilung der Pazifischen Komponente starken Veränderungen auf dekadischen Zeitskalen unterliegt aber auch in den Süßwasserverteilungen im Transpolaren Drift Strom wurden 2007 starke Variationen beobachtet welche somit auf zusätzliche jährliche Variationen hinweisen. Es ist nicht bekannt ob die 2007 beobachteten Variationen ein permanentes Phänomen sind und ob diese mit dem weitgehenden Fehlen des Pazifischen Wassers in diesem Zeitraum zusammenhängen. Die geplante flächendeckende und quantitative Erfassung der Süßwasserverteilung und des Pazifischen Wassers werden daher dazu beitragen, den Einfluss und die möglichen Rückkopplungsmechanismen der arktischen Hydrographie auf den arktischen und globalen Klimawandel weitergehend zu verstehen.

T!Raum - One Health - Etablierung einer Standard-Diagnostik des Mikrobioms agrikultureller Böden

Laboruntersuchungen zum Verhalten von 14C-markierten Pflanzenschutzmitteln im Boden

In Saeulenversuchen, Abbauversuchen unter konstanten und variierenden Klimabedingungen und Batchversuchen zur Bindungsfaehigkeit werden in Hinblick auf die mathematische Simulation des Stoffverhaltens Daten erarbeitet. Forschungsziel ist es dabei, solche Laborversuche im Hinblick auf ihre Eignung zur Verwendung in Simulationsmodellen zu ueberpruefen und zu optimieren.

Cyto-genetische Untersuchungen zur Lokalisierung von Resistenzgenen beim Roggen (Secale cereale L.)

Erweiterung des Kenntnisstandes der Genetik des Roggens und Erarbeitung von Grundlagen fuer eine gezielte Kombinationszuechtung. Isolierung morphologisch abweichender Roggenlinien aus spaltenden Populationen. Auslese von Pflanzen mit induzierten Chromosomenstueckumbauten (Translokationen) aus bestrahltem Material. Selektion von Linien mit je einem zusaetzlichen Chromosom (trisome Linien) aus Valenzkreuzungen selbstfertiler Inzuchtlinien. Zuordnung von morphologischen Markern, Translokationen und Trisomen zu den entsprechenden Chromosomen (Kopplungsgruppen). Spaeterhin: Ermittlung genetischer Abstaende.

Erstellung einer Kopplungskarte fuer Lein (Linium usitatissium) mit molekularen Markern

Untersuchungen ueber den Einfluss von Bodenparametern auf die Verlagerung von Radiojod im Boden

Assessment and Prediction of the Mechanical Impact on the Subsoil by the Installation of Gas Pipelines in Agricultural Soils

Heavy machinery used for the construction or transport gas pipelines can cause severe and persistent subsoil compaction of agricultural land, depending on various factors among which soil wetness plays a key role. In this project, several field experiments were carried out to investigate the stress propagation under heavy construction machines (40 t and more) during operation on selected plot areas under controlled moisture conditions, to assess the resulting mechanical deformation of the subsoil and to investigate changes of soil properties in particular infiltration patterns of a dye tracer analyzed by computer image analysis. In the laboratory , oedometric compressibility and other properties, in particular bulk density and coarse porosity, of soil samples taken before and after the impact by the machines were determined and compared to measurements of control samples. Furthermore, we investigated the moisture-dependence of the precompression stress by a series of oedometer tests and also performed some shear tests for the purpose of model parameter estimation. Using only a priori parameter values determined from such independent soil tests or just best estimates, the critical-state soil-mechanical model CRISP was used to interpret the results. As far as field observations were available they agreed well with the model simulations. The results lend support to the hypothesis that preconsolidation stress provides a suitable criterion to protect soils against overloading. However, the moisture-dependence of this parameter needs to be better known. Given that homogeneity of the experimental field sites had been a prime criterion of selection, spatial variability between trafficked and untrafficked test plots was still surprisingly large and limiting the detectability of compaction effects more than anticipated.

Porewater chemistry, iron extractions, metabolic rates and microbial analyses from Boknis Eck sediments from January 2022 until March 2023

We collected sediments for pore water analyses via IC, ICP-OESm H2S and Alkalinity measurements, conducted sequential Fe-extractions, determined O2 consumption rates via an enclosed mini Chamber, measured sulfate reduction rates via 35S-SO4 tracer and conducted 16S rRNA amplicon gene analyses (seqeuncing Illumina). Data was generated from Boknis Eck sediments from January 2022 until March 2023.

Nitrate and hydrogen sulfide concentrations of the water column in the Kiel Bight, SW Baltic Sea from 2018 to 2025

This dataset presents hydrogen sulfide (H2S) and nitrate (NO3-) concentrations in the water column at 15 stations in the Kiel Bight taken during the research cruises BE10/2018 (23.10.2018), BE03/2019 (15.03.2019), L23-13 (13.09.2023 - 15.09.2023), Hai24VE2 (24.09.2024) and EMB374 (04.09.2025 - 13.09.2025). Water samples were collected using Niskin bottles attached to a stainless-steel framework with CTD sensors. Concentrations of H2S and NO3- were measured photometrically (Hitachi U-2900). The data are used to describe seasonal hypoxia in the Kiel Bight water column and are combined with sediment and porewater data to identify controlling factors governing the accumulation of H2S at the seafloor. Furthermore, we compare the H2S measurements from the deepest Niskin bottle with bottom water H2S concentrations obtained from the benthic tracer profiler and from the overlying water in sediment cores. This allows us to illustrate H2S trends from several meters above the seafloor down to the sediment-water interface, and to discuss advantages and limitations of the different sampling techniques in characterizing geochemical conditions in the benthic environment.

Global database of sedimentary excess thorium-234 (Th-234) in and near submarine canyons

This global compilation was generated to explore the application of thorium-234 (234Th) as a tracer for recent sedimentation in submarine canyons. Submarine canyons are located along the continental margins, including the shelf regions, which are disproportionally relevant for the carbon cycle and other essential biogeochemical processes. These geomorphological features can act as funnels for particles and represent a strong connection between land and the open ocean. The continental margins encompass dynamic environments, granting the necessity to use tracers capable of quantifying short-term events. 234Th is a particle reactive radionuclide that gets scavenged onto particles in the water column and, due to its short half-life of 24.1 days, it allows estimating the magnitude of recently deposited sediment on the seabed over the previous ~4 months. Excess 234Th (234Thxs) with respect to 234Th in secular equilibrium with its parent nuclide uranium-238 can be used to calculate excess 234Th inventories as a proxy of recent sediment deposition (Aller and Cochran, 1976). Moreover, the vertical profile of 234Thxs in surface sediment also serves for estimation of mixing rates when sedimentation rates are sufficiently low. This has advantages over the classic and extensively used lead-210 dating method with a decadal integration period (Arias-Ortiz et al., 2018), since the relatively short time scale of 234Th can match the occurrence of recent short deposition events, thus revealing the impacts of potential recent riverine runoff, trawling-derived deposition or phytoplankton blooms, among others. To compile these data we conducted a search across Google Scholar (last accessed: 03-Sep-2025 ) for periods encompassing 1979-2025, and obtained 123 search results using the terms: (Excess 234Th OR Excess 234 Th OR Excess Th-234 OR Excess Thorium-234) AND (submarine canyon OR canyon OR off-shelf) AND (sediment core OR sediment samples OR core OR gamma spectrometry OR gamma spectroscopy OR gamma counting OR radiochemical analysis OR radioisotopic). After thorough inspection of the publications, those reporting sedimentary 234Th data in canyon environments were selected, resulting in a compilation of data from a total of 26 publications from 20 different canyons. Data on 234Thxs parameters, sampling methodology, and contextual information of sediment cores obtained in submarine canyon environments were carefully extracted using the information given in the main text, tables, figures, and supplementary files. Latitude, longitude and sampling dates were assigned to the midpoint or the sampling month when not explicitly stated. Gamma spectrometry was applied as the counting method, with one exception measured by beta counting. Empty cells represent missing data. In 12 studies, data was also provided from the shelf, slope or abyssal plain near the canyon. The compilation includes surface 234Thxs activities, 234Thxs penetration depths, 234Thxs inventories and mixing rates (Db) from canyon studies with coring sites inside canyons, spanning a depth range from 120 to 4280 m and, additionally, near those canyons. In canyons, the most frequently provided parameter is the surface 234Thxs activity (19 of 26 studies) ranging from 20 to 4040 Bq kg-1with a mean value of 520 Bq kg-1. 10 of 26 studies reported 234Thxs inventories, showing high variability with a range of values between 10 and 50700 Bq m-2 and a mean value of 2860 Bq m-2. 10 of 26 studies reported (or provide enough data for extraction of) 234Thxs penetration depths (mean of 2 cm, ranging from 0.4 to 24 cm). The least frequently reported 234Thxs parameter is mixing rate (6 of 26 studies) yet encompassing a large range of values from 0.2 to 68.7 cm2 y-1 with a mean of 6.9 cm2 y-1.This database provides an overview of the variability of recent sediment deposition patterns as well as other sedimentary parameters derived from 234Th measurements across canyons distributed globally. Advancing the characterization of short-term sedimentary signatures using 234Th is promising and relevant in canyon environments, which represent a crucial link in the land-ocean interface.

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