ALBERT

Description: Underway optical chlorophyll-a and turbidity data were collected along the cruise track with Sea-Bird Scientific ECO FLNTU sensors installed within two autonomous measurement systems, called self-cleaning monitoring boxes (SMBs). The SMBs measure alternatingly. While one box is measuring, the other one is being cleaned. At the beginning of the transect, the boxes switched to operation every three hours, later, while the ship is transecting the Pacific Gyre, the cleaning interval was changed to only every 24 hours. The water inlet for the SMBs is at about 4 m depth. The data were quality controlled and the chlorophyll-a data were additionally calibrated using discrete water samples. In situ chlorophyll-a samples were collected by the scientific party from Niskin bottles during CTD stations and underway using a tow fish. Chlorophyll-a of these samples was determined in the lab on board using a bench top fluorometer. Details on all quality control steps, the calibration, as well as a comparison to satellite data can be found in the data processing report. The resulting data set contains the original data and corresponding quality flags and, in case of chlorophyll-a, additionally the calibrated data plus quality flag. The data source is given through the name of the active SMB. The data set contains data during transect and station. We recommend to use ship's speed to filter for only transect data.

Description: High-resolution multi-proxy records from two lakes on the southern Tibetan Plateau, Nam Co and Tangra Yumco, are used to infer long-term variations in the Asian monsoon system. We examine the moisture evolution during the Late Glacial Maximum and Holocene using the trace element and stable isotope composition of ostracod shells. The sediment records covering the past 24 cal. ka BP and 18 cal. ka BP, respectively, demonstrate the suitability of ostracod shell chemistry as paleoenvironmental proxy. We analysed (i) Mg/Ca, Ba/Ca and Sr/Ca ratios as salinity proxies, (ii) Fe/Ca, Mn/Ca and U/Ca ratios representing redox conditions and microbial activity, and (iii) rare earth elements (REEs) reflecting weathering and changes in provenance.

Description: This dataset presents benthic foraminiferal δ¹⁸O chronostratigraphies for International Ocean Discovery Program (IODP) Site U1541, Ocean Drilling Program (ODP) Site 1090 and ODP Site 980-981 based on different tuning targets including LR04 (Lisiecki and Raymo, 2005), LR09 (Lisiecki and Raymo, 2009), CENOGRID (Westerhold et al., 2020) and Probstack (Ahn et al., 2017) obtained by Middleton et al. (2024). The benthic foraminiferal δ¹⁸O record for IODP Site U1541 (54°13'S, 125°25'W) recently recovered from the central South Pacific on IODP Expedition 383 (Winckler et al., 2021) is shown for the first time and is published in Middleton et al. (2024). All data records are based on Cibicidoides wuellerstorfi and Cibicides kullenbergi, or combinations thereof. The dataset provides the basis for investigating and discussing the uncertainties of benthic foraminiferal δ¹⁸O stratigraphies for conventional manual and automated tuning techniques and evaluate their impact on sedimentary age models over the past 3.5 Myr (Middleton et al., 2024).

Description: In July 2022 within the framework of an Alfred-Wegener-Institute-managed expedition and the Nunataryuk project, sediment cores were taken at three locations, off the coast of Herschel Island, Canada, using a hand corer: YC22_MR_6: 69°34'23.12N, 138°54'37.76W; 3 m water depth; July 6th 2022 YC22_MR_7: 69°34'23.53N, 138°56'37.66W, 6 m water depth; July 7th 2022 YC22_MR_8: 69°30'22.75''N, 138°53'21.69''W; 45 m water depth; July 24th 2022 Data sets were obtained to investigate carbon feedback from the sediments to the water column and atmosphere, using DIC concentrations and isotopic values. The local sediments are supplied primarily by organic carbon previously stored in adjacent permafrost soils (biomarker and bulk data), which erode and redeposit quickly (age model) on the ocean floor. The acquired data includes: 1) Sediment data: Bulk total organic carbon content (Lamping et al., 2021) and its isotopic values for 13C (Brodie et al., 2011; Werner & Brand, 2001) and 14C (Mollenhauer et al., 2021) and Biomarker data: Quantifying alkanes (CPI) , and fatty acids (TAR ratio) as described by Wei et al. (2020), Glycerol dialkyl glycerol tetraethers (GDGTs basis for BIT-Index) after Hopmans et al. (2016), Hopanes (fßß) following instructions by Meyer et al., (2019), and Sterols (Dinosterol) after Dauner et al. (2022). 2) Porewater was extracted from the cores using rhizomes and quantified as described in Oni et al., (2015). Dissolved inorganic carbon isotope signatures were determined as CO2 for 13C (Torres et al., 2005) and 14C (Mollenhauer et al., 2021). 3) Intact polar lipid fatty acids were extracted from the sediments, purified, and 14C analysis was performed as described in Ruben et al. (2023). The 13C isotopy was determined with GC-IRMS (Elvert et al., 2003). The respective precursor lipids of the polar fraction used for isotope analysis were quantified following the method described in Wörmer et al. (2013). Datasets are to be found at doi:10.1594/PANGAEA.966262 and doi:/10.1594/PANGAEA.966264. 4) Sedimentary age model of core YC22_MR_7 assuming constant rate of supply (CRS) model (Appleby, 2001), based on data obtained with a HPGe gamma detector.

Description: We present results of Th/U dating, stable isotope and trace element data from a speleothem from Puerto Rico. Th/U dating was performed using isotope dilution MC-ICPMS. Activity ratios were corrected for initial Th assuming an detrital weight ratio 232Th/238U = 0.154 ± 0.038 (corresponding to an activity ratio of the detritus in secular equilibrium of (230Th/232Th)detr = 19.79 ± 4.93), and secular equilibrium of the detritus. Ages are calculated using the decay constants by Cheng et al. (2000)). Uncertainties are given as 2σ- range, and do not include half-life uncertainties. Th/U dating shows that stalagmite PR-LA-1 covers the period from 15.4 to 46.2 ka with a growth interruption between 35.5 and 41.1 ka. Stable isotope samples were drilled with a spatial resolution of 1 mm and measured using an IRMS equipped with a Gasbench. Element/Calcium ratios of the speleothem were measured by laser ablation ICPMS and were reduced to the resolution of the stable isotope records.

Description: We present a new speleothem trace element and stable isotope record, which extends previous paleoclimate evidence from Cuban speleothems to the last 96 ka. Stable isotope samples were micromilled at a resolution of 0.10-0.33mm, and measured using an IRMS equipped with a Gasbench. Line scans of Element/Calcium ratios of the speleothem were measured by laser ablation ICPMS and were reduced to the resolution of the stable isotope records.

Description: We present a new speleothem trace element and stable isotope record, which extends previous paleoclimate evidence from Cuban speleothems to the last 96 ka. Stable isotope samples were micromilled at a resolution of 0.10-0.33mm, and measured using an IRMS equipped with a Gasbench. Line scans of Element/Calcium ratios of the speleothem were measured by laser ablation ICPMS and were reduced to the resolution of the stable isotope records.

Description: Culturing experiments exposed the scleractinian corals Porites lobata and Porites lichen to a mixture of dissolved chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), silver (Ag), cadmium (Cd), tin (Sn), mercury (Hg) and lead (Pb) in a wide concentration range for a period of more than a year. The aim was to examine whether the incorporation of heavy metals into the aragonitic skeleton of the corals is a direct function of their concentration in seawater. Therefore, the trace-element-to-calcium ratio (TE/Ca) in the coral aragonite precipitated during culturing was measured by Laser ablation ICP-MS in 2020. The measurement showed that all metals used here were measureable in the coral skeleton and only minor, non-systematic intra- and interspecies differences in the trace metal concentrations was found. A positive correlation between the TE/Ca values and the coral skeleton was found for Cr, Mn, Ni, Zn, Ag, Cd and Pb. Cu, Sn and Hg did not show any clear trend. This dataset shows time resolved trace element-to-calcium values of coral colonies A to D cultured in the metal system along the measured Laser ablation ICP-MS scanning lines (Line XY stands for different Laser ablation lines measured at different positions at one respective coral colony) and values derived from the composite lines. Measurements were carried out from the top of the coral to the bottom and the distance starting from the top is indicated as “Elapse Time”. The energy density of the laser was set to 10 J/cm3, the laser spot size was 120 µm diameter and the stage moved 50 µm/s. Prior to every scan, a preablation pass with a spot size of 160 µm diameter was carried out to clean the cut surface of the coral skeleton. Culturing experiments were configured with two identically experimental aquaria. Four different coral colonies and two different species were used (Porites lobate Coral A-C, Porites lichen Coral D). All colonies were divided into subcolonies and growth control was performed with Alizarin Red S prior and during the experiment. One subcolony was placed in each experimental tank. The control aquarium remained unmodified while the trace metal concentration in the metal aquarium was elevated stepwise (Phase 1-4, Phase 1 = lowest metal concentration). The trace metal concentration in both tanks was monitored during the culturing period. After the experiment and more than 15 months later, specimens were cut again and the trace metal concentration in the coral skeleton was determined. It should be noted that coral D died 2.5 weeks after the exposure to the highest metal concentration in phase 4. TE/Ca values are processes as followed: (1) Time resolves raw intensities (in counts per seconds) for all isotopes measured were processed with the software Iolite (Version 4). The determination of element/Ca ratios was performed after the method of Rosenthal et al. (1999). High values of 25Mg, 27Al or 55Mn at the beginning of an ablation profile were related to contamination on the surface of the coral or remains of organic matter and these parts of the profiles were excluded from further data processing. (2) The NIST SRM 612 glass (Jochum et al., 2011) was used for monitoring and correction of the instrument drift. (3) The detection limit was defined by 3.3*SD of the gas blank in counts per seconds for every element in the raw data. Only values above this limit were used for further analyses and no data below the LOQ (limit of quantification = 10*SD) were interpreted. After processing the data with Iolite, an outlier detection of the TE/Ca ratios of the samples was performed. If trace metal values from deviated more than ±2SD from the average of the samples from the corresponding culturing phase, values were defined as outliers and discarded. (4) A composite line was calculated individually for all colonies consisting of the laser ablation measurements along the main growth axis of the coral (coral A line 1-3, coral B line 1-3, coral C line 2 + 3, coral D line 1). Laser ablation measurements along lines that were deviating from the main growth axis of the coral were not taken into account. Calculations were performed with QAnalyseries (Kotov and Paelike, 2018).

Description: For trace element analyses, single specimens of C. wuellerstorfi have been analyzed using femtosecond laser ablation inductively coupled plasma mass spectrometry (fs-LA-ICP131 MS) at the Geochemistry Laboratory at the Max Planck Institute for Chemistry. Na, Mg, and Sr of 142 specimens of C. wuellerstorfi have been measured at high-resolution on (up to) each of the final five chambers to eliminate possible inaccuracies that are likely to be caused by varying sample size. The fs-LA-ICP-MS analyses were performed on 25-μm diameter spots on each chamber with a pulse repetition rate of 15 Hz at low fluence (0.1-0.3 J/cm2). Calibration was performed with the microanalytical synthetic reference material MACS‐3 for carbonate and NIST612 for silica. Average values of all chambers analyzed in the same specimen were used for further analyses. Since foraminifers from different regions show particular offsets in the Mg/Ca composition of their shell, depending on region specific temperature ranges of ambient seawater, region-specific formulas are used. We have applied the formula Mg/Ca=0.82e^0.19*BWT of Tisserand et al. (2013) from samples collected from similar geographic situations to avoid offsets. The formula has been applied to calculate temperature variability of each analyzed chamber. The average value obtained from chamber-to-chamber temperature variability of each specimen has been applied as average temperature data of the entire test.

Description: Here, we present a global compilation of previously reported sightings of the rare planktic foraminifer Globorotalia cavernula Bé, 1967 as well as new observations of live-collected specimens from the Southern Ocean (Subantarctic south of Africa). The goal of this synthesis is to provide the geographic and stratigraphic context needed to investigate the past and present-day distributions of this rare but possibly under-recognized species. The previous records include modern occurrences in the water column (collected by plankton net tows and a single sediment trap) and seafloor sediments ranging in age from recent to Eocene. Seafloor sediment samples were collected by dredge, sediment grabs and core-tops. Deeper sediments came from drilling cores. Existing databases provided a foundation for this compilation, particularly ForCenS for surface sediments (Siccha & Kucera, 2017) and FORCIS for water-column collections (de Garidel-Thoron et al., 2022; Chaabane et al., 2022, 2023). These records were supplemented with occurrences from the literature, PANGEA, and cruise reports of the Deep Sea Drilling Project (DSDP) / Ocean Drilling Program (ODP). Searches were conducted in October 2022 using Google Scholar, GBIF, EOL (Encyclopedia of Life, "http://eol.org", which includes records from the Smithsonian NMNH). Where available, we include information on the abundance of G. cavernula in each collection, and indicate whether photographic evidence (or drawings) could be found to support the identification. Globorotalia crozetensis Thompson, 1973 (reclassified as G. cavernula by Brummer & Kučera, 2022) and closely related Globorotalia petaliformis Boltovskoy, 1974 were also included in compilation.

Description: This study examined the metabolic response of juvenile turbot (Scophthalmus maximus) to diets with graded fishmeal (FM) replacement with plant, animal, and emerging protein sources (PLANT, PAP, and MIX) in comparison to a commercial-like diet (CTRL). The feeding experiment was carried out from April to July 2019 in the Centre for Aquaculture Research (ZAF) at the Alfred Wegener Institute for Polar and Marine research in Bremerhaven, Germany. The juvenile turbot (Scophthalmus maximus) were purchased from France Turbot (L'Épine, France) and acclimated to the recirculating aquaculture system (RAS) for 2 weeks prior to starting the 16 weeks experimental trial. To elucidate the effects of the protein sources and the level of FM replacement on the metabolic response of the fish, a 1H‐nuclear magnetic resonance (NMR) spectroscopy was used to assess the metabolic profiles of muscle and liver tissue after feeding the fish the experimental diets for 16 weeks. Feed, muscle, and liver samples were ground under liquid nitrogen and approx. 200–250 mg tissue was homogenized in 5x volume of ice‐cold 0.6 M perchloric acid (PCA) (w:v). After one cycle of 20 s at 6000 rpm and 3 °C, using Precellys 24 (Bertin Technologies, Montigny‐le‐Bretonneux, France), samples were sonicated for 2 min at 0 °C and 360 W (Branson Sonifier 450, FisherScientific, Schwerte, Germany). Homogenates of the experimental diets, muscle and liver tissues were centrifuged for 2 min at 0 °C and 16,000 g, and supernatants were neutralized with ice cold potassium hydroxide (KOH) and PCA to pH 7.0–7.5. To remove precipitated potassium, perchlorate samples were centrifuged again for 2 min at 0 °C and 16,000 g. The entire supernatant was transferred, shock‐ frozen in liquid nitrogen, and stored an −80 °C for later analysis. One‐dimensional 1H‐NMR spectra for feed and tissues extracts were acquired using a vertical 9.4 T wide bore magnet with Avance III HD (Bruker‐GmbH, Ettlingen, Germany) at 400.13 MHz with a 1.7 mm diameter triple tuned (1H‐13C‐15N) probe. Each spectrum was processed and analyzed with Chenomx NMR Suite 8.4 software (Chenomx Inc., Edmonton, Canada). Before analyzing, the spectra were corrected for phase, shim and baseline and calibrated to trymethylsilyl proprionate (TSP) signal (at 0.0 ppm).

Description: Presence-absence records for four cold-water coral (CWC) taxa (Enallopsammia rostrata, Acanella arbuscula, Metallogorgia spp. and Paramuricea spp.) were gathered to conduct distribution models on seamounts (Cadamosto, Nola, Senghor and Cabo Verde) of the Cabo Verde archipelago (NW Africa), covering a bathymetric range from 2100 to 750 m water depth. Data were extracted from video footage collected with Remotely Operated Vehicles during the M80/3 Meteor (2010) and the iMirabilis2 (2021) research expeditions. Video data from the iMirabilis2 expedition was analysed, quantitively, using the open-source software BIIGLE (Langenkämper et al. 2017). Observations from five continuous 1 to 2 km-long video transects between 2000 and 1400 m depth at Cadamosto Seamount were converted into presence-absence data points. Similar data were not available for the seamounts explored during M80/3 Meteor. However, all the available images and short video clips from that expedition were analysed to identify presence and absence points for each of the four target CWC taxa. All the available presence/absence data from the two expeditions was transformed into one point per grid cell of a 100 m resolution bathymetry grid, with the prevalence of the presence records over the absence records, in grid cells where both categories overlapped.

Description: Data presented here were collected between January 2022 to November 2022 within the research unit DynaCom (Spatial community ecology in highly dynamic landscapes: From island biogeography to metaecosystems) of the Universities of Oldenburg, Göttingen, and Münster, the iDiv Leipzig and the Nationalpark Niedersächsisches Wattenmeer. Experimental islands and saltmarsh enclosed plots were created in the back barrier tidal flat and in the saltmarsh zone of the island of Spiekeroog. Sediment samples for the determination of pore-water salinity were taken bi-/monthly in surface sediments (0-3 cm depth) of the experimental plots. Samples were stored dark and cool (8°C) until measurement. Samples were measured in the laboratory within two months after sampling according to DIN ISO 11265:1997-06. In the laboratory, sediment samples for the determination of pore-water salinity were weighed in pre-weighed Falcon™ 50 mL conical centrifuge tubes (10 g sediment on average, depending on sand content). After one month of air-drying samples were re-weighed to determine dry weight and therefore the loss in weight. Ultrapure water was added to the tubes and were homogenized using a pestle. Salinity was measured directly in the tubes with a HQ40D Digital two channel multi meter and a pre-calibrated Intellical CDC401 field 4-poles graphite conductivity cell (Hach Lange GmbH, Germany). Post-processing of measured values were done using MATLAB (R2018a). Quality control was performed by (a) visually checks, and hence (b) the classification into quality control flags using quality check algorithms

Description: The data comprise processed active-source seismic data acquired with ocean bottom seismometer (OBS) data. The data were collected at Venere mud volcano during expedition POS515 with the research vessel POSEIDON (Riedel et al., 2017) in the Mediterranean Sea, Calabrian Arc offshore southern Italy (map under further details). The entire data set consists of 11 OBS stations. Seismic data were shot across the OBS along seven profiles. Each OBS consist of 4 channels (channel 1: hydrophone; channel 2: horizontal component 1; channel 3: horizontal component 2; channel 4: vertical component).

Description: The data comprise continuous records of seismic raw data acquired with ocean bottom seismometers (OBS). The data were collected at Venere mud volcano during expedition POS515 with the research vessel POSEIDON (Riedel et al., 2017) in the Mediterranean Sea, Calabrian Arc offshore southern Italy (map under further details). The entire data set consists of 11 OBS stations. Each OBS consist of 4 channels (channel 1: hydrophone; channel 2: horizontal component 1; channel 3: horizontal component 2; channel 4: vertical component). Data are not corrected for clock-drift. Data format is Passcal-SEGY. Data are accessible using the seismological software tools provided by EarthScope: https://www.passcal.nmt.edu/content/software-resources. The data were recorded using: HTI-04_PCA_ULF hydrophones from High Tech Inc., Short-period 4.5 Hz geophones and three-component seismometers (K/MT-210 manufactured by KUM GmbH). The recording device is an MBS recorder of SEND GmbH.

Description: The data set constitutes a total of 84 2D multichannel seismic lines acquired in parallel 2D mode across Venere mud volcano. An additional 7 lines were acquired across a grid of 12 OBS deployed in the region. Data are fully processed and migrated (in time). Main processing steps include: Geometry definition, Common-Mid-(CMP) Point sorting, Normal-Moveout-Corrention (NMO) using an average velocity function (extracted from ocean-bottom-seismometer data), Stacking and FK-Migration (in time). Data processing was completed using the VISTA processing package, provided by Schlumberger to GEOMAR. Data acquisition for this survey started with profile P1001 on June 21, 2017 (at 17:30, CET) at a position of 38°34.42'N, 17°08.66'E. Data acquisition for this survey ended with profile P1102 on July 2, 2017 (at 04:00, CET) at a position of 38°40.39'N, 17°07.97'E.

Description: The data comprise processed active-source seismic data acquired with ocean bottom seismometers (OBS). The data were collected at Poseidon mud volcano chain during expedition POS515 with the research vessel POSEIDON (Riedel et al., 2017) in the Mediterranean Sea, Calabrian Arc, offshore southern Italy. The entire data set consists of 12 OBS stations. Seismic data were shot across the OBS along 14 2D profiles. Each OBS consist of 4 channels (channel 1: hydrophone; channel 2: horizontal component 1; channel 3: horizontal component 2; channel 4: vertical component).

Description: Foraminiferal shells of the species M. velascoensis from sediments spanning ~650 ka across the PETM section of ODP Site 865, Central Pacific, were embedded in epoxy and polished to midsection. Suitable, well-preserved domains for in-situ analysis were identified by scanning electron microscopy. In-situ measurements of the Mg/Ca ratios were performed using a CAMECA SX-51 electron microprobe housed in the Cameron and Wilcox Microbeam Laboratory at the UW-Madison Department of Geoscience. Depending on the number of suitable targets for analysis, between one and seven Mg/Ca measurements were performed for each shell. Fully quantitative microanalyses (mineral standards, background subtracted, and matrix corrected) were performed using Probe for EPMA software (Probe Software, Inc.). The natural carbonate standards Delight Dolomite and Callender Calcite were used for Mg and Ca, respectively. Mg-K alpha X-rays were measured on two spectrometers and aggregated. Carbon was calculated within the matrix correction, being allocated as one atom of carbon to 3 atoms of oxygen, and oxygen by stoichiometry to the cations measured, thus analytical totals of 98 – 100.5 wt. % are a measure of accuracy. Analyses featuring analytical totals below 98 wt. % or above 100.5 wt. % were excluded from the data set.

Description: The occurrence of previously geochemically identified tephra allowed refinement of the age-depth model by comparison with previously established volcanic eruption history (Roeser et al., 2012). Tephra layers were polished on thin sections and the glass shards were geochemically characterized using a JEOL JXA-8230 Electron Probe X-ray Micro Analyzer (EMPA; ISTerre Laboratory, University Grenoble Alpes) equipped with 5 wavelength dispersive spectrometers (WDS) and one energy dispersive spectrometer (EDS) detector. The measurements used the following conditions: 15 kV voltage, 2 nA beam current, and 5 to 7 µm beam size. For standardization, MPI-DING glasses (StHs6/80-G, GOR132-G) (http://georem.mpch-mainz.gwdg.de; Jochum et al., 2000), natural minerals, and synthetic oxides were used. Two glasses, Atho-G (http://georem.mpch-mainz.gwdg.de; Jochum et al., 2000) and KE-12 (Metrich & Rutherford, 1992), were analyzed together with the samples to verify analytical accuracy and to exclude the loss of alkalis. Analyses of glass shards yielding a total oxide sum less than 96% or suggesting mineral impurities were not included in this study. Analytical data were normalized to 100% total oxide values to enable comparison.

Description: The occurrence of previously geochemically identified tephra allowed refinement of the age-depth model by comparison with previously established volcanic eruption history (Roeser et al., 2012). Tephra layers were polished on thin sections and the glass shards were geochemically characterized using a JEOL JXA-8230 Electron Probe X-ray Micro Analyzer (EMPA; ISTerre Laboratory, University Grenoble Alpes) equipped with 5 wavelength dispersive spectrometers (WDS) and one energy dispersive spectrometer (EDS) detector. The measurements used the following conditions: 15 kV voltage, 2 nA beam current, and 5 to 7 µm beam size. For standardization, MPI-DING glasses (StHs6/80-G, GOR132-G) (http://georem.mpch-mainz.gwdg.de; Jochum et al., 2000), natural minerals, and synthetic oxides were used. Two glasses, Atho-G (http://georem.mpch-mainz.gwdg.de; Jochum et al., 2000) and KE-12 (Metrich & Rutherford, 1992), were analyzed together with the samples to verify analytical accuracy and to exclude the loss of alkalis. Analyses of glass shards yielding a total oxide sum less than 96% or suggesting mineral impurities were not included in this study. Analytical data were normalized to 100% total oxide values to enable comparison.

Description: In July 2022 within the framework of an Alfred-Wegener-Institute-managed expedition and the Nunataryuk project, sediment core YC22_MR_7 was taken off the coast of Herschel Island, Canada, using a hand corer. Data sets were obtained to investigate carbon feedback from the sediments to the water column and atmosphere, using DIC concentrations and isotopic values. The local sediments are supplied primarily by organic carbon previously stored in adjacent permafrost soils (biomarker and bulk data), which erode and redeposit quickly (age model) on the ocean floor. Porewater was extracted from the cores using rhizomes and quantified as described in Oni et al., (2015). Dissolved inorganic carbon isotope signatures were determined as CO2 for 13C (Torres et al., 2005) and 14C (Mollenhauer et al., 2021).

Description: In July 2022 within the framework of an Alfred-Wegener-Institute-managed expedition and the Nunataryuk project, sediment core YC22_MR_8 was taken off the coast of Herschel Island, Canada, using a hand corer. Data sets were obtained to investigate carbon feedback from the sediments to the water column and atmosphere, using DIC concentrations and isotopic values. The local sediments are supplied primarily by organic carbon previously stored in adjacent permafrost soils (biomarker and bulk data), which erode and redeposit quickly (age model) on the ocean floor. Porewater was extracted from the cores using rhizomes and quantified as described in Oni et al., (2015). Dissolved inorganic carbon isotope signatures were determined as CO2 for 13C (Torres et al., 2005) and 14C (Mollenhauer et al., 2021).

Description: In July 2022 within the framework of an Alfred-Wegener-Institute-managed expedition and the Nunataryuk project, sediment core YC22_MR_7 was taken off the coast of Herschel Island, Canada, using a hand corer. Data sets were obtained to investigate carbon feedback from the sediments to the water column and atmosphere, using DIC concentrations and isotopic values. The local sediments are supplied primarily by organic carbon previously stored in adjacent permafrost soils (biomarker and bulk data), which erode and redeposit quickly (age model) on the ocean floor. Sedimentary age model of core YC22_MR_7 assuming Constant Flux: Constant Sedimentation (CFCS) model (Appleby, 2001), based on data obtained with a HPGe gamma detector.

Description: In July 2022 within the framework of an Alfred-Wegener-Institute-managed expedition and the Nunataryuk project, sediment core YC22_MR_6 was taken off the coast of Herschel Island, Canada, using a hand corer. Data sets were obtained to investigate carbon feedback from the sediments to the water column and atmosphere, using DIC concentrations and isotopic values. The local sediments are supplied primarily by organic carbon previously stored in adjacent permafrost soils (biomarker and bulk data), which erode and redeposit quickly (age model) on the ocean floor. Porewater was extracted from the cores using rhizomes and quantified as described in Oni et al., (2015). Dissolved inorganic carbon isotope signatures were determined as CO2 for 13C (Torres et al., 2005) and 14C (Mollenhauer et al., 2021).

Description: This dataset provides the data for the four glass standards used for monitoring of the precision and accuracy of electron probe microanalyses (EPMA) during analytical runs of cryptotephra glass-shards in the International Continental Scientific Drilling Program (ICDP) sediment core 5017-1 (see first dataset). For each EPMA run, all four glass standards were measured. The major-element composition of the glass standards was measured using a JEOL JXA-8230 electron microprobe at GFZ Potsdam, Germany (15 kV, 5-10 nA, 5-10 µm beam size). Instrumental calibration used natural mineral standards. Glass standards were Lipari obsidian (Hunt & Hill 1996, doi:10.1016/1040-6182(95)00088-7; Kuehn et al. 2011, doi:10.1016/j.quaint.2011.08.022) and MPI-Ding glasses ATHO-G, StHs-6-80-G and GOR-132-G (Jochum et al. 2006, doi:10.1029/2005GC001060).

Description: This dataset presents user-defined tiepoints of the manual alignment of the benthic foraminiferal δ¹⁸O record at IODP Site U1541 to the benthic foraminiferal LR04 δ¹⁸O stack of Lisiecki and Raymo (2005) obtained by Middleton et al. (2024). The benthic foraminiferal δ¹⁸O record for IODP Site U1541 is based on stable isotope analyses of Cibicidoides wuellerstorfi and Cibicides kullenbergi, and was published in Middleton et al. (2024).

Description: This dataset presents tie points between sediment core PS75/059-2 and IODP Site U1541 based on an alignment of high-resolution X-ray fluorescence (XRF) Fe intensity variations in both cores, obtained by Middleton et al. (2024). The splicing of the two cores provides the basis for a combination of the benthic foraminiferal δ¹⁸O records for PS75/059-2 (Ullermann et al., 2016) and IODP Site U1541 (Middleton et al., 2024).

Description: The data are a processed and interpolated P-Cable 3D seismic data cube. The data were collected during expedition POS515 with the research vessel POSEIDON (Riedel et al., 2017) in the Mediterranean Sea, Calabrian Arc offshore southern Italy (map under further details). Seismic source was a Generator-Injector airgun fired in harmonic GI mode with generator and injector volume of 105 cubic inches. The source was towed at a nominal depth of 2 m beneath the sea surface. We deployed a P-Cable system made from 12 parallel streamers (each 12. 5 m in length). Details on the towed geometry are given in Figure 30 of the cruise report (Riedel et al., 2017). The P-Cable data were acquired over the course of 6 days during POS515 starting from 13:45 on July 5, 2017 until 12:06 on July11, 2017 (all CET). Processing included: 3D geometry application, trace editing, static time corrections, band-pass filtering, sorting to common midpoint gathers, normal moveout correction (1520 m/s velocity ), and stacking. The stacked 3D cube was then interpolated to fill any empty bins. Afterwards, Stolt time migration (1550 m/s) was performed, first inline, then crossline direction. The dataset has a horizontal resolution of 3.125 m (bin size) and a dominant frequency of ~100 Hz.

Description: The data set contains 13 2D multichannel seismic lines acquired across Poseidon mud volcano chain, Caalbrian Arc, offshore southern Italy. Data were processed onboard during expedition POS515 with R/V POSEIDON. These lines were also recorded on 12 OBS. Details see cruise report (Riedel et al., 2017). Main processing steps include: Geometry definition, Common-Mid-(CMP) Point sorting (1.5625 m bin-space), Normal-Moveout-Corrention (NMO) using a constant velocity of 1500 m/s and Stacking Stolt-Migration (in time) with constant velocity of 1500 m/s. Data processing was completed onboard using the SU processing package. Seismic Surveying at Poseidon mudvlcano started with line P4001 on July 3, 2017 (08:22 am, CET) at 17°40.12'E, 38°21.58N. The last line acquired in this sequence is line P6010. Surveying ended on July 5, 2017 at 04:00 am (CET) at 17°43.12'E, 38°18.96'N.

Description: Data presented here were collected between January 2022 to November 2022 within the research unit DynaCom (Spatial community ecology in highly dynamic landscapes: From island biogeography to metaecosystems) of the Universities of Oldenburg, Göttingen, and Münster, the iDiv Leipzig and the Nationalpark Niedersächsisches Wattenmeer. Experimental islands and saltmarsh enclosed plots were created in the back barrier tidal flat and in the saltmarsh zone of the island of Spiekeroog. Sediment samples for the determination of pH, water content and loss on ignition were taken bi-/monthly in surface sediments (0-3 cm depth) from the experimental plots. Samples were stored dark and cool (8°C) until measurement. Samples were measured in the laboratory within two months after sampling. Water content (w, [-]) was determined by first weighing the fresh sample (mf; ~ 3-7 g) in pre-weighed aluminium trays and than placed in the drying chamber at 105 °C for 12 hours. After placing samples in the exsiccator for 60 min., samples were re-weight to determine dry weight (md). Water content was calculated using w = (mf - md) / md . Afterwards, samples were placed in the muffle furnace for 2 hours at 430 °C within their aluminium trays, and placed again in the exsiccator for 60 min. Samples were re-weighed to determine the new dry weight (mgl) to calculate loss on ignition (LOI, [%]) using LOI = ((md – mgl) / md ) * 100 . Values of pH were measured according to DIN ISO 10390. Therefore, soil samples were weighed in pre-weighed Falcon™ 50 mL conical centrifuge tubes. Sediment samples were homogenized using a pestle. Ultrapure water was used to measure pH directly within the tubes using a HQ40D digital two channel multi meter and an Intellical PHC101 field low maintenance gel filled pH electrode (Hach Lange GmbH, Germany). The pH electrode was calibrated before measurement using singlet pH buffer sets (pH 4.01, 7.00, 10.01) for single use (Hach Lange GmbH, Germany). Post-processing of measured values were done using MATLAB (R2018a). Quality control was performed by (a) visually checks, and hence (b) the classification into quality control flags using quality check algorithms.

Description: The data comprise continuous records of seismic raw data acquired with ocean bottom seismometers (OBS). The data were collected at Poseidon mud volcano chain during expedition POS515 with the research vessel POSEIDON (Riedel et al., 2017) in the Mediterranean Sea, Calabrian Arc offshore southern Italy (map under further details). The entire data set consists of 12 OBS stations. Each OBS consist of 4 channels (channel 1: hydrophone; channel 2: horizontal component 1; channel 3: horizontal component 2; channel 4: vertical component). Data are not corrected for clock-drift. Data format is Passcal-SEGY. Data are accessible using the seismological software tools provided by EarthScope: https://www.passcal.nmt.edu/content/software-resources. The data were recorded using: HTI-04_PCA_ULF hydrophones from High Tech Inc., Short-period 4.5 Hz geophones and Three-component seismometers (K/MT-210 manufactured by KUM GmbH). The recording device is an MBS recorder of SEND GmbH

Description: In July 2022 within the framework of an Alfred-Wegener-Institute-managed expedition and the Nunataryuk project, sediment core YC22_MR_7 was taken off the coast of Herschel Island, Canada, using a hand corer. Data sets were obtained to investigate carbon feedback from the sediments to the water column and atmosphere, using DIC concentrations and isotopic values. The local sediments are supplied primarily by organic carbon previously stored in adjacent permafrost soils (biomarker and bulk data), which erode and redeposit quickly (age model) on the ocean floor. The acquired data includes: 1) Sediment data: Bulk total organic carbon content (Lamping et al., 2021) and its isotopic values for 13C (Brodie et al., 2011; Werner & Brand, 2001) and 14C (Mollenhauer et al., 2021). 2) Biomarker data: Quantifying alkanes (CPI) , and fatty acids (TAR ratio) as described by Wei et al. (2020), Glycerol dialkyl glycerol tetraethers (GDGTs basis for BIT-Index) after Hopmans et al. (2016), Hopanes (fßß) following instructions by Meyer et al., (2019), and Sterols (Dinosterol) after Dauner et al. (2022).

Description: This dataset presents user-defined tiepoints of the manual alignment of the benthic foraminiferal δ¹⁸O record at ODP Site 980 and 981 to the benthic foraminiferal LR04 δ¹⁸O stack of Lisiecki and Raymo (2005) obtained by Middleton et al. (2024). The benthic foraminiferal δ¹⁸O record at ODP 980 is based on Cibicidoides wuellerstorfi and Cibicides kullenbergi, and was previously published (McManus et al., 1999; Flower et al., 2000; Oppo et al., 1998). The ODP Site 981 data were measured on benthic foraminifera of the genus Cibicidoides (Raymo et al., 2004). The benthic foraminiferal δ¹⁸O records of ODP Site 980 and 981 were spliced together at ~860 ka (Raymo et al., 2004).

Description: This dataset presents user-defined tiepoints of the manual alignment of the benthic foraminiferal δ¹⁸O record at ODP Site 1090 to the benthic foraminiferal LR04 δ¹⁸O stack of Lisiecki and Raymo (2005) obtained by Middleton et al. (2024). The benthic foraminiferal δ¹⁸O record is based on Cibicidoides wuellerstorfi and was previously published in Hodell et al. (2000) and Venz and Hodell (2002).

Description: This dataset presents benthic foraminiferal δ¹⁸O chronostratigraphies and associated uncertainties for International Ocean Discovery Program (IODP) Site U1541, based on different tuning targets including LR04 (Lisiecki and Raymo, 2005), LR09 (Lisiecki and Raymo, 2009), CENOGRID (Westerhold et al., 2020) and Probstack (Ahn et al., 2017) and based on manual versus automated tuning techniques (Middleton et al., 2024). The benthic foraminiferal δ¹⁸O record for IODP Site U1541 (54°13'S, 125°25'W) recently recovered from the central South Pacific on IODP Expedition 383 (Winckler et al., 2021) is presented for the first time in Middleton et al. (2024). It is based on stable isotope analyses of Cibicidoides wuellerstorfi and Cibicides kullenbergi (Middleton et al., 2024), and was combined with the benthic foraminiferal δ¹⁸O record of PS75/059-2 (Ullermann et al., 2016). Automated tuning is based on Hidden Markov Model (HMM)-Match-based alignments (Middleton et al., 2024) generated using the automated probabilistic HMM-Match algorithm of Lin et al. (2014). The manual tuning was generated by visual alignment of characteristic peaks and troughs of the benthic foraminiferal δ¹⁸O record of IODP Site U1541 to the benthic foraminiferal LR04 stack using the publicly available QAnalySeries software (Kotov and Pälike, 2018). The dataset provides the basis for investigating and discussing the uncertainties of benthic foraminiferal δ¹⁸O stratigraphies for conventional manual and automated tuning techniques and evaluate their impact on sedimentary age models over the past 3.5 Myr (Middleton et al., 2024).

Description: This dataset presents benthic foraminiferal δ¹⁸O chronostratigraphies and associated uncertainties for Ocean Drilling Program (ODP) Site 1090, based on different tuning targets including LR04 (Lisiecki and Raymo, 2005), LR09 (Lisiecki and Raymo, 2009), CENOGRID (Westerhold et al., 2020) and Probstack (Ahn et al., 2017) and based on manual versus automated tuning techniques (Middleton et al., 2024). The benthic foraminiferal δ¹⁸O record at ODP Site 1090 is based on Cibicidoides wuellerstorfi and was previously published in Hodell et al. (2000) and Venz and Hodell (2002). Automated tuning is based on Hidden Markov Model (HMM)-Match-based alignments (Middleton et al., 2024) generated using the automated probabilistic HMM-Match algorithm of Lin et al. (2014). The manual alignments of ODP Site 1090 were obtained by realigning the original age model tie points (Venz and Hodell, 2002) to the benthic foraminiferal LR04 δ¹⁸O stack using the QAnalySeries software (Kotov and Pälike, 2018). The dataset provides the basis for investigating and discussing the uncertainties of benthic foraminiferal δ¹⁸O stratigraphies for conventional manual and automated tuning techniques and evaluate their impact on sedimentary age models over the past 2.9 Myr (Middleton et al., 2024).

Description: This dataset presents benthic foraminiferal δ¹⁸O chronostratigraphies and associated uncertainties for Ocean Drilling Program (ODP) Site 980 and 981, based on different tuning targets including LR04 (Lisiecki and Raymo, 2005), LR09 (Lisiecki and Raymo, 2009), CENOGRID (Westerhold et al., 2020) and Probstack (Ahn et al., 2017) and based on manual versus automated tuning techniques (Middleton et al., 2024). The benthic foraminiferal δ¹⁸O record at ODP 980 is based on Cibicidoides wuellerstorfi and Cibicides kullenbergi, and was previously published (McManus et al., 1999; Flower et al., 2000; Oppo et al., 1998). The ODP Site 981 data were measured on benthic foraminifera of the genus Cibicidoides (Raymo et al., 2004). The benthic foraminiferal δ¹⁸O records of ODP Site 980 and 981 were spliced together at ~860 ka (Raymo et al., 2004). Automated tuning is based on Hidden Markov Model (HMM)-Match-based alignments (Middleton et al., 2024) generated using the automated probabilistic HMM-Match algorithm of Lin et al. (2014). The manual alignments of ODP Site 980/981 were obtained by realigning the original age model tie points (e.g., Raymo et al., 2004) to the benthic foraminiferal LR04 δ¹⁸O stack using the QAnalySeries software (Kotov and Pälike, 2018). The dataset provides the basis for investigating and discussing the uncertainties of benthic foraminiferal δ¹⁸O stratigraphies for conventional manual and automated tuning techniques and evaluate their impact on sedimentary age models over the past 1.8 Myr (Middleton et al., 2024).

Description: In July 2022 within the framework of an Alfred-Wegener-Institute-managed expedition and the Nunataryuk project, sediment core YC22_MR_7 was taken off the coast of Herschel Island, Canada, using a hand corer. Data sets were obtained to investigate carbon feedback from the sediments to the water column and atmosphere, using DIC concentrations and isotopic values. The local sediments are supplied primarily by organic carbon previously stored in adjacent permafrost soils (biomarker and bulk data), which erode and redeposit quickly (age model) on the ocean floor. The precursor lipids of the polar fractions used for isotope analysis were quantified following the method described in Wörmer et al. (2013). Quantified lipid classes include: betaine lipids (BL), phosphatidyl-(N)-monomethylethanolamine (PME), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG) and lyso-DPG.

Description: Foraminiferal assemblage data was collected from the top 0-1 cm sediment layer of 30 surface samples from the Mauritanian slope and shelf. The material was sampled with a box corer (50x50x55cm), grabs and gravity corer (6m lenght) during the expedition MSM16/3 of RV Maria S. Merian in October-November 2010. The samples range from water depths of 13 m on the shelf to 1310 m on the middle bathyal slope. They are from the inner and outer shelf, upper bathyal slope, canyons, coral mounds, the cold-water coral reef chains at 400–600 m water depth and the middle bathyal slope. The samples were washed over a 250 µm sieve and dried. Per sample 200 benthic foraminiferal specimens were counted on species level. 154 were documented with illustrations and descriptions. The purpose of the study was to investigate the foraminiferal faunas of the Mauritanian shelf and upper slope and their association with cold water coral habitats.

Description: In July 2022 within the framework of an Alfred-Wegener-Institute-managed expedition and the Nunataryuk project, sediment core YC22_MR_7 was taken off the coast of Herschel Island, Canada, using a hand corer. Data sets were obtained to investigate carbon feedback from the sediments to the water column and atmosphere, using DIC concentrations and isotopic values. The local sediments are supplied primarily by organic carbon previously stored in adjacent permafrost soils (biomarker and bulk data), which erode and redeposit quickly (age model) on the ocean floor. Intact polar lipid fatty acids were extracted from the sediments, purified, and 14C analysis was performed as described in Ruben et al. (2023). The 13C isotopy was determined with GC-IRMS (Elvert et al., 2003).

Description: This dataset describes a series of aerosol and meteorological measurements collected in the Great Barrier Reef (GBR) Marine Park collected during the "GBR as a significant source of climatically relevant aerosol particles" campaign, known as "Reef to Rainforest" (R2R). The data covers a broad area of the GBR marine park (-27.3091 to -16.95169 latitudinally, 145.9705 to 154.1146 longitudinally) over approximately one month, from 28th September, 2016 to 24th October, 2016. The data was collected at two sites – one aboard the Australian Government Research Vessel Investigator (RVI), and an onshore site at Garner's Beach, QLD, Australia (-17.8222S, 146.1023E). Parameters measured include particle size distribution, number concentration, composition cloud condensation nuclei (CCN) properties, concentrations of gases and markers including black carbon, radon, carbon monoxide, carbon dioxide, volatile organic compounds (VOCs), dimethylsulfide (DMS), upper air particle concentration/composition, cloud or low lying fog presence, cloud top height, depolarisation ratio, aerosol scattering and optical thickness. The observations were collected in the hope of improving our understanding of the local climate and aerosol properties, which in turn will improve local models and better inform regulatory bodies protecting the GBR.

Description: Along with the radiation measurements, ROV positions were obtained from acoustic LBL (Long BaseLine)-positioning and all parameters of vehicle depth, distance to the ice and attitude recorded. All times are given in UTC.

Description: Along with the radiation measurements, ROV positions were obtained from acoustic LBL (Long BaseLine)-positioning and all parameters of vehicle depth, distance to the ice and attitude recorded. All times are given in UTC.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The dataset comprises elemental data that was obtained on sediment samples from sub-Antarctic South Georgia. The sediments were collected from a range of different sites, including lakes, peat deposits, a marine inlet and a fjord during RV Polarstern expedition PS81 in 2013. Prior to the geochemical analyses reported here, the sediments were freeze-dried and ground. More details on the study sites, sampling and data evaluation can be found in Berg et al. (submitted manuscript). Total organic carbon (TOC) was analyzed with a DIMATOC 200 (DIMATEC Corp., Canada) analyser. The TOC concentration is derived from the difference between total carbon (TC) and total inorganic carbon (TIC). Total carbon (C), total nitrogen (N) and sulfur (S) were analyzed using a Vario Micro Cube combustion elemental analyser (Elementar, Germany).

Description: The dataset comprises N-alkane composition data that was obtained on sediment samples from sub-Antarctic South Georgia. The sediments were collected from a range of different sites, including lakes, peat deposits, a marine inlet and a fjord during RV Polarstern expedition PS81 in 2013. Prior to the geochemical analyses reported here, the sediments were freeze-dried and ground. More details on the study sites, sampling and data evaluation can be found in Berg et al. (submitted manuscript). Alkyl lipid biomarkers were extracted by accelerated solvent extraction (ASE 300, Thermo, USA) with dichloromethane and methanol (DCM, MeOH; 9:1, v/v at 120°C, 75 bar) (cores Co1305, PS81/283, and Co1308) or via consecutive ultrasonication in DCM:Hexan (1:1), MeOH:DCM (1:1) and MeOH (core Co1306 and the peat and soil samples). The total lipid extract (TLE) was saponified with 0.5 M KOH in MeOH and water (9:1, v/v) at 80°C for 2 h. Neutral lipids (NL) were extracted from the TLE with dichloromethane by liquid-liquid phase separation. Alkanes were purified from NL by silica gel column chromatography (SiO2, deactivated, mesh-size 60) by elution with hexane. Analysis was conducted by gas chromatography (GC, Agilent 7890B, Agilent Technologies, USA) equipped with a flame ionization detector (FID). Alkanes were identified and quantified against authentic external standards. Concentrations are given as fractional abundances for the compound class.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: The distance between a remotely operated vehicle (ROV) and the sea-ice underside was measured by a single-beam upward-looking acoustic sonar altimeter (Tritech PA500) attached to the ROV during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition between November 2019 and September 2020. Sea-ice draft was derived by subtracting the distance to the sea-ice underside from the ROV depth, uncorrected for ROV attitude (pitch, roll). An offset between the depth reference (ROV bumper bars) and the altimeter of 0.105 m is accounted for in the presented data.

Description: This dataset contains 3 minute resolution data with measurements from the SMPS (SMPS – TSI 3080 Classifier) and Condensation Particle Counters (CPC3787, CPC3782 and CPC3772). The SMPS gives the size distribution and the CPC gives the total particle number concentration. The number following the X is the midpoint diameter of the SMPS size bin, in nm. For instance, X11.3 denote the size bin with a diameter midpoint of 11.3 nm. As not all the CPCs were available to be used at all times, a linear model was used to model the total particle number concentration based off measurements from the three CPCs.