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Found 13 results.

Total organic carbon in sediment cores from the Kiel Bight, SW Baltic Sea from 2016 to 2025

This dataset presents total organic carbon (TOC, wt%) contents in sediments at 19 stations in the Kiel Bight taken during the research cruises BE03/2016 (08.03.2016), BE10/2016 (19.10.2016), BE10/2018 (23.10.2018), BE03/2019 (15.03.2019), L23-13 (13.09.2023 - 15.09.2023), Sagitta24-1 (16.09.2024), Sagitta24-2 (23.09.2024), L25-2b (09.02.2025 - 17.02.2025) and EMB374 (04.09.2025 - 13.09.2025). Sediment cores (<50cm) were recovered using a Multicorer (MUC), Minicorer (MIC) or Rumohrlot (RL). The TOC analysis was performed using an Element Analyzer (Euro EA 3000). The data are used in combination with porewater and water column data to describe the sulfur geochemistry and cycling across different sites in the Kiel Bight and to identify the controlling factors governing the accumulation of hydrogen sulfide at the seafloor.

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.

Dissolved oxygen concentrations, temperature and salinity of the water column in the Kiel Bight, SW Baltic Sea from 2018 to 2025

This dataset presents dissolved oxygen (O2) concentrations, temperature and salinity profiles with water depths at 61 stations in the Kiel Bight, collected 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). The data were measured using dissolved oxygen, temperature and conductivity sensors (Sea-Bird, SBE43) attached to a stainless-steel framework. Temperature and salinity data are used to identify stratification patterns within the water column. Together with the O2 measurements, these data are used to characterize the seasonal development of hypoxia in the deep waters of the Kiel Bight. This understanding of hypoxic conditions is then combined with sediment and porewater data to identify controlling factors governing the accumulation of H2S at the Kiel Bight seafloor.

Porewater ion concentrations and total alkalinity in the Kiel Bight, SW Baltic Sea from 2016 to 2025

This dataset presents porewater and bottom water data from 63 stations in the Kiel Bight taken during the research cruises BE03/2016 (08.03.2016), BE10/2016 (19.10.2016), BE10/2018 (23.10.2018), BE03/2019 (15.03.2019), L23-13 (13.09.2023 - 15.09.2023), Sagitta24-1 (16.09.2024), Sagitta24-2 (23.09.2024), L25-2b (09.02.2025 - 17.02.2025) and EMB374 (04.09.2025 - 13.09.2025). Short sediment cores (<50cm) were recovered using a Multicorer (MUC), Minicorer (MIC) or Rumohrlot (RL). At 22 of those stations, bottom water and porewater samples were analysed for total alkalinity (TA), ammonium (NH4+), sulfate (SO42-), hydrogen sulfide (H2S), dissolved iron (Fe2+) and dissolved manganese (Mn2+). At 41 stations, exclusively a bottom water sample was taken for H2S measurements. Bottom waters were sampled from the supernatant water in the sediment cores. Porewater samples were extracted from the sediments using rhizones. TA was determined by titration (METROHM 876 Dosimat Plus), NH4+ and H2S using a photometer (Hitachi U-2900), SO42- by Ion Chromatography (METROHM 761 Compact) and Fe2+ and Mn2+ by Inductively Coupled Plasma Optical Emission Spectroscopy (Varian 720-ES). The collected data will be used to determine the spatial and temporal variability of hydrogen sulfide in bottom waters of the Kiel Bight, (ii) identify the controlling factors governing the accumulation of hydrogen sulfide at the seafloor, and (iii) establish an early warning system of sulfidic seafloor conditions for regional stakeholders in the Baltic Sea.

Sulfate reduction rates in sediments and bottom water from Kiel Bight, SW Baltic Sea 2023 to 2025

This dataset presents microbial sulfate reduction rates (SRR) from eight stations, in Kiel Bight, near Fehmarn and Flensburg Fjord. Sediments and water column samples were taken during the research cruises BE-09/2023 (12.09.2023), L23-13 (13.09.2023 – 15.09.2023), AL618 (18.08.2024 – 08.09.2024), Sagitta24-1 (16.09.2024), Sagitta24-2 (23.09.2024), Hai24VE2 (24.09.2024), BE01/2025 (23.01.2025), L25-2b (09.02.2025 – 17.02.2025) and EMB374 (04.09.2025 - 13.09.2025). Sediment cores were recovered using Multicorer or Rumohrlot. Subcores were taken from the cores and 35S radiotracer was added centimeter-wise, incubated for 17-24 hours at in-situ temperature of the retrieved cores, sliced, transferred in zinc acetate and stored at -20°C until analysis. Water samples were collected by a CTD/Rosette at 3 different water depth (1, 2, 6 m asf) and from bottom water of the sediment cores. 35S radiotracer was added directly to the samples incubated for 17-24 hours at in-situ temperature and proceeded as for sediments. The analysis followed in the laboratory at the home institute and sulfate reduction rates were quantified after Kallmeyer et al. (2004), using cold chromium distillation, with modifications after Roy et al. (2014). The data set provides the first spatial overview of SRR variability in Kiel Bight and reveals differences between the late summer conditions in the years 2023, 2024 and 2025, as well as winter conditions from 2025. Together with microbiological, geochemical, sensor, and benthic chamber data the results help to better understand spatial and temporal variations in sedimentary sulfide production, retention and emission to the bottom water of Kiel Bight.

Sensor data from a benthic chamber experiment in the Kiel Bight, SW Baltic Sea from 2025

This dataset consists of sensor data from field experiments with time-series point measurements. These benthic MiniChamber experiments were run at five stations for 20 h during cruise EMB374 (04.09.2025 - 13.09.2025). An O2 optode with integrated temperature sensor (Aanderaa, Norway), as well as pH and sulfide micro sensor (Unisense, Denmark), were measuring within the benthic chamber during the 20 h experimental run. The data set will be used to highlight similarities and differences in the benthic system of the Kiel Bight. Oxygen respiration and sulfide flux rates from the benthic chamber can be extrapolated to larger areas of Kiel Bight, providing insights into more widespread occurrences of sulfide emissions.

Sedimentary sensor data from the Kiel Bight, SW Baltic Sea from 2024 and 2025

This dataset consists of sensor data from eight stations, in Kiel Bight, near Fehmarn and Flensburg Fjord. It includes vertical depth profiles. For the vertical depth profiles sediments were taken during research cruises Sagitta24-1 (16.09.2024), Sagitta24-2 (23.09.2024), BE01/2025 (23.01.2025), L25-2b (09.02.2025 – 17.02.2025) and EMB374 (04.09.2025 - 13.09.2025). In 2024, oxygen, pH and sulfide were measured, whereas redox potential and hydrogen were additionally measured in 2025. Micro sensor equipment of Unisense (Aarhus, Denmark) was used for all sediment profiles. The data set will be used to highlight small-scale vertical gradients that are putatively microbial induced and altered as well as geochemical differences between the upper sediment of Kiel Bight. Together with microbiological and geochemical data and rate measurements the data will show the close interlinkages between sediment properties and communities.

Discrete water sample data from a benthic chamber experiment in the Kiel Bight, SW Baltic Sea from 2025

This dataset consists of geochemical parameters like hydrogen sulfide, total alkalinity (TA), phosphate, nitrite, nitrate, silicate, ammonium, chloride, bromide and sulfate data from five stations with benthic chamber experiments during EMB374 (04.09.2025 - 13.09.2025) in the Kiel Bight. Samples were collected with a syringe sampler within the benthic chamber at the end of incubation time as well as from ambient bottom water by Niskin bottles mounted to the MiniLander at around 20 cm above the seafloor. Sampling took place at the same time as with the syring sampler within the benthic chamber. Concentrations of hydrogen sulfide were measured photometrically, TA was titrated with a dosimeter, phosphate, nitrite, nitrate, silicate, ammonium were measured with an autoanalyzer and chloride, bromide, sulfate with an ion chromatograph. Together with the sensor measurements, this data set provide key parameters necessary for understanding biogeochemical processes, calculating oxygen respiration rates and sulfide emission rates from the sediment to the water column within the benthic chamber.

Water column, solid phase and porewater data in the Kiel Bight, SW Baltic Sea from 2016 to 2025

During the research cruises BE03/2016 (08.03.2016), BE10/2016 (19.10.2016), BE10/2018 (23.10.2018), BE03/2019 (15.03.2019), L23-13 (13.09.2023 - 15.09.2023), Sagitta24-1 (16.09.2024), Sagitta24-2 (23.09.2024), Hai24VE2 (24.09.2024), L25-2b (09.02.2025 - 17.02.2025) and EMB374 (04.09.2025 - 13.09.2025), CTDs were deployed and sediment corers were retrieved at 131 stations in Kiel Bight in the southwestern Baltic Sea. Water column oxygen concentrations, temperature and salinity were determined using oxygen and CTD sensors. At selected water depths, water samples were collected with Niskin bottles for the analysis of nitrate concentrations using an autoanalyzer. Short sediment cores (<50cm) were recovered using a Multicorer (MUC), Minicorer (MIC) or Rumohrlot (RL). Bottom waters were sampled from the supernatant water in the sediment cores. Solid phase sediment samples were analyzed for total organic carbon using an element analyzer. Porewater was extracted from the sediment cores uzing rhizones and analyzed for total alkalinity (titration), ammonium (photometer), sulfate (ion chromatography), hydrogen sulfide (photometer), dissolved iron (ICP-OES) and dissolved manganese (ICP-OES). The collected data will be used to (i) determine the spatial and temporal variability of hydrogen sulfide in bottom waters of the Kiel Bight, (ii) identify the controlling factors governing the accumulation of hydrogen sulfide at the seafloor, and (iii) establish an early warning system of sulfidic conditions for regional stakeholders in the Baltic Sea.

Microbial sulfate reduction rates, geochemical micro profiles and benthic chamber experiment data in the Kiel Bight, SW Baltic Sea from 2023 to 2025

This dataset collection presents measurements of microbial sulfate reduction rates (SRR), mircrosensor profiles, and benthic chamber experiments from eight stations, in Kiel Bight, near Fehmarn and Flensburg Fjord from 2023 to 2025. Sediment cores were recovered using multicorer (MUC), minicorer (MIC) or Rumohr lot (RL), with multiple core liners (MUC/MIC) used per deployment for microbial, geochemical, and sensor analysis. The dataset provides the first spatial and temporal overview of sulfide production in sediment and water column of Kiel Bight, small-scale putatively microbial influenced vertical gradients of the upper sediment, and flux rates between sediment and bottom water. Further geochemical data from the same deployments can be found in Spiegel et al. 2026 https://doi.pangaea.de/10.1594/PANGAEA.988013. Together these datasets enable assessments of microbial-geochemical controls on sulfide production, retention, and emission to the bottom water of Kiel Bight under changing regimes.

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