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XRF and grain size analyses of sediment cores GeoB18303-2 and GeoB18304-1
No full textTwo cores, GeoB18303-2 and 18304-1 were collected using a marine vibrocorer during cruise M102 offshore Durban, South Africa in December 2013. These were collected under the auspices of the joint German-South African project Regional Archives for Integrated Investigations (RAIn), in order to examine climate changes on the east coast of South Africa. Core GeoB18303-2 was acquired at 29° 49,84' S 31° 9,73' E in a water depth of 67.9 m. Core GeoB18304-1 was acquired at 29° 49,14' S 31° 7,62' E in a water depth of 39.2 m. The cores were analysed for downcore elemental chemistry and grain size trends using a Panalytical Epsilon 3 XL XRF machine at the University of Bremen, Germany. Both terrigenous and bulk grain sizes were analyzed using a Coulter laser particle sizer LS 13 320 at the MARUM, University of Bremen, Germany. The quantitative XRF data for Cores GeoB18303-2 and GeoB18304-1 are displayed as weight percentage (wt%) at 5 cm intervals with depth down core. The grain size (bulk and clastic) data for Cores GeoB18303-2 and GeoB18304-1 are displayed as phi values at 5 cm downcore sample resolution
Corrected UK'37 and SST estimates of ODP Site 145-883
No full textThe gas chromatography chemical ionization mass spectrometry (GC-CI-MS) technique used to generate the 5.7 million year alkenone sea surface temperature (SST) dataset from ODP Site 145-882 introduced a systematic bias into the SST data, an issue that was characterized subsequently to the generation of the ODP Site 145-882 alkenone dataset (Chaler et al. 2000, doi:10.1021/ac001014q; 2003, doi:10.1016/S0021-9673(03)01188-9; Haug et al, 1995). The dataset archived here is a corrected version of the ODP Site 145-882 alkenone SST record that more closely agrees with published GC-FID data (Haug et al, 2005, doi:10.1038/nature03332; Martinez-Garcia et al., 2010, doi:10.1126/Science.1184480; Novak et al. 2024, doi:10.1038/s41561-024-01500-7; Studer et al, 2012, doi:10.1016/j.epsl.2012.07.029).
The correction introduced larger uncertainties in the SSTs than is typical in alkenone sea surface temperature reconstructions. Because we lack instrument-specific information about the ionization efficiencies of the alkenone homologues on the GC-CI-MS used by Haug et. al (1995) to generate the ODP 145-882 alkenone SST dataset, we could not use the equations of Chaler et al. (2003, doi:10.1016/S0021-9673(03)01188-9) to correct their record. Instead, we used a simple linear regression between proximal samples of Haug et al. (1995) and Studer et al. (2012, doi:10.1016/j.epsl.2012.07.029), who used the more typical gas chromatography flame ionization detector (GC-FID) technique. The standard error of this relationship (2.5°C) was added to the uncertainty in BAYSPLINE alkenone SST estimates in quadrature
Stratigraphic tie points of sediment core PS69/899-2
No full textThe age model for PS69/899-2 (doi:10.1594/PANGAEA.983936) was developed using a combination of stratigraphic markers and Undatable age-depth modeling routine (Lougheed and Obrochta, 2019). Stratigraphic markers employed include TEX86-based SST, RPI, radiocarbon ages on total sedimentary organic matter, and the last occurence datum of the diatom Rouxia leventerae (Zielinski et al., 2002). The TEX86-based SST record from core PS69/899-2 was aligned with the Antarctic temperature stack compiled from ice core data (Parrenin et al., 2013), while the RPI record was aligned with the PISO-1500 paleointensity stack (Channell et al., 2009). Radiocarbon ages were calibrated using the Marine 20 calibration data (Heaton et al., 2023), assuming a marine reservoir age of 1200 years for the Holocene and of 2200 years for glacial periods (Rafter et al., 2022)
Age model of sediment core PS97/085-3
No full textAge model of PS97/085-3 28 – 58 ka BP. Model is based on correlating relative paleointensities and magnetic inclination with the Black Sea core stack of Wu et al. (2021), on the correlation of XRF scan derived ln(Ca/Ti) to EDC temperature anomalies (AICC2023), and on the correlation of ln(Ca/Ti) and grain size to δ18O of EDML (AICC2023). The model is an update of the one of Wu et al. (2021)
Epilithic biofilm, water chemistry and catchment data collected from lakes and streams in South Greenland in August 2022
No full textThis dataset contains measurements of physico-chemical parameters, biofilm, and watershed characteristics from subarctic lakes and streams in the Narsaq area, Greenland, collected in August 2022. Water samples were collected and analyzed for temperature, conductivity, alkalinity, and nutrient concentrations. Biofilm samples were collected from stones, with chlorophyll a (Chl a), ash-free dry weight (AFDW), and carbon-to-nitrogen (C:N) ratios measured. Algal pigments were analyzed using HPLC for taxonomic composition. Watershed delineation was performed using a digital elevation model (DEM), and vegetation greenness was quantified via the normalized difference vegetation index (NDVI) using Sentinel-2 satellite imagery. This dataset contributes to understanding the environmental drivers of biofilm biomass and community composition in Arctic freshwater ecosystems
Averaged 2015-2024 plastic fluxes from the Mediterranean coastal population retrieved from the nighttime light imagery
No full textDue to strong concerns about plastic pollution in the Mediterranean Sea, source-related plastic fluxes have been estimated. We represent the fluxes from the coastal population, which make up more than 60% of plastics emitted into the Mediterranean (Kaandorp et al., 2020). The novel dataset is based on global nighttime light products, which provide a visual representation of humanity's presence. Data from the NASA/NOAA Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) onboard the Suomi National Polar-orbiting Platform (SNPP) are used as proxies for population-related plastic inputs that are difficult to map directly across a basin. We process the monthly cloud-free composites provided by the Earth Observation Group at the National Geophysical Data Center in Boulder, Colorado, US (Elvidge et al., 2017; doi:10.1080/01431161.2017.1342050). Four fundamental assumptions have been made: (1) plastic pollution is connected to light pollution; (2) annual plastic flux from the coastal Mediterranean population is set at 1000 tons (Kaandorp et al., 2020; doi:10.1021/acs.est.0c01984); (3) a 20-kilometer coastal belt is the zone where plastic emissions from coastal populations in the Mediterranean originate; (4) the country-specific correction factors are derived from Human Development Indices. (Mai et al., 2023; doi:10.1021/acs.est.0c02273). At a resolution of 15 arcseconds, the data quantify the averaged plastic fluxes 2015–2024 in kg per day from the coastal area to the sea. For user convenience, two datasets are provided: one with country-specific corrections and one without. The data are represented in seaward cells and are ready for modeling plastic transport in the Mediterranean Sea. The dataset can also be used to develop a source-specific observational strategy for plastic pollution
Relative proportions of sterols in Melosira assemblages, and subsequently isolated unialgal cultures collected in June 2023 during the RV Kronprins Haakon cruise 2023-1 in Fram Strait
No full textDuring the AO2023-1 expedition (1-21 June 2023), Melosira assemblages were collected using a handpump at a sampling site in Fram Strait. In addition to performing physiological measurements and filtering the material for trophic markers (fatty acids, stable isotope ratios of fatty acids, sterols and highly branched isoprenoids (HBIs), living material was brought back to Akvaplan-niva in Oslo and two strains were established as unialgal cultures. The cultures are maintained in artificial seawater-based L1 medium at 4°C and 25 µmol m-2 s-1 light with a 16:8 L:D cycle. Lipids were extracted from freeze-dried samples following the method of Folch et al. (1957), using a dichloromethane/methanol mixture (2:1, v/v) in a sonication bath. Thereafter, lipids were saponified with 20% potassium hydroxide in water/methanol (1:9). Sterols were extracted with hexane, purified by open-column chromatography with SiO2 and eluted with methanol. Sterol fractions were derivatized using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). Sterols were analyzed with gas chromatography–mass spectrometry (Agilent 7890B, Agilent Technologies), equipped with a DB-1ms column (30 m length, 0.25 mm internal diameter, 0.25 μm film thickness) and an Agilent 5977A MSD, following Stein et al. (2025). The temperature program ranged from 60°C to 320°C. Sterols were quantified using an internal standard (androstanol). Sterol analysis was conducted to complement datasets on fatty acid proportions and fatty acid stable isotope compositions. Collectively, the datasets enable a detailed characterization of the biochemical composition of different Melosira arctica-dominated algal assemblages from the Arctic Ocean, and a comparison with a unialgal culture of this important species
Methane and nitrous oxide sea-air fluxes from western Long Island Sound
No full textThis dataset contains methane and nitrous oxide dissolved gas concentration (https://doi.pangaea.de/10.1594/PANGAEA.987944), sea-air fluxes (this dataset), and ancillary hydrographic data from research cruises in western Long Island Sound occurring in August 2023, October 2023, and May 2024. Water samples for methane and nitrous oxide analysis were collected from Niskin bottles mounted on a CTD rosette. Water was collected into glass serum bottles and at least three volumes of water were allowed to flow through the sample before it was preserved and sealed with a butyl rubber stopper and aluminum crimp seal. Gas concentrations were determined using a headspace equilibration method and gas chromatograph with electron capture detector (for nitrous oxide) and flame ionization detector (for methane). Equilibrium dissolved concentrations were calculated from the measured temperature and salinity following the solubility equations of Wiesenburg and Guinasso (1979) for methane and Weiss and Price (1980) for nitrous oxide. Dry atmospheric concentrations were set to 2020 ppbv for methane and 338 ppbv for nitrous oxide and adjusted to 100% humidity. These concentrations are taken from preliminary surface flask results from Mashpee, Massachusetts, USA (station MSH) from the NOAA Carbon Cycle Greenhouse Gases group website (https://gml.noaa.gov/ccgg/) and represent the average over the three cruises (Dlugokencky et al., 2020b, a; Hall et al., 2007). Oxygen concentration was determined using an oxygen sensor mounted on the Niskin rosette, calibrated with discrete samples analyzed by Winkler titration (Langdon et al., 2010), which were also collected from the CTD rosette. The mixed layer depth was defined based on a potential density difference criterion of 0.125 kg/m³ relative to the shallowest measurement (either 2 or 3 m), using CTD profiles binned to 1 m. The 15-day weighted gas transfer velocities and fluxes are calculated using wind speeds measured over 15 days at 15-minute intervals prior to sampling using the data from NOAA buoy 44022 with weighting based on the fraction of the mixed layer ventilated during each time step following the method of Teeter et al. (2018) as described in the main manuscript of Manning et al. (2025) and software of Manning and Nicholson (2022)
Th-U ages over the last 112,000 years from Devils Hole calcite (NV, USA) for palaeo water table reconstruction
No full textU-series measurements to constrain the age of Devils Hole cave 2's submerged calcite (Nevada, USA). Samples originate from 9 horizontally drilled cores of 0.5 to 1.3m length and 2.5cm diameter. They were taken from the hanging wall at elevations between +3.2 m and +9.9 m relative to the modern water table. Sampling was done between the years 2015 and 2023. Samples for dating are all taken from mammillary calcite which precipitates from the groundwater underneath the water table. The sequence of mammillary calcite and Folia which only grows at the water table surface allow to reconstruct a water table history. Depending on the sequence of mammillary calcite and Folia, samples represent the following types: ( i ) the water table increased above this elevation, ( d ) the water table decrease to below this elevation, ( b ) water table rose briefly above this elevation and then dropped below it again, ( x ) water table was above this elevation (see method section of Steidle et al. (2024) for details). 230Th/U ages were calculated. The updated record of water-table changes enables a comparison with sea-level records between 120,000 to 70,000 years ago, revealing concurrent changes in both during this period. This strengthens the hypothesis that orbital-scale water-table changes are closely linked to ice-sheet expansion during Marine Isotope Stage 5. New water table markers of the last 60,000 years further support increased pluvial conditions during Heinrich events