cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.1594/pangaea.971695
title: An expert survey on chamber measurement techniques and approaches for calculation and quality control of methane fluxes

description: This data set contains the responses to an expert survey on chamber measurements of methane (CH4) fluxes from 36 participants working in 11 countries each of whom had at least one field season of experience in chamber measurements. The expert survey covered questions on demographic information, the research sites and research topics of the participants, their measurement setups, and their flux calculation methods. The survey, furthermore, contained an exercise on visual quality control in which the participants were asked to decide between keeping or discarding 12 chamber measurements or parts of them based on the behavior of the CH4, carbon dioxide (CO2), and water vapor (H2O) concentrations measured in the chamber over time and to explain their decisions. We calculated the CH4 fluxes based on a linear fit to the time periods chosen by the participants. The calculated CH4 fluxes as well as the raw chamber measurement data for this visual quality control are included in this data set. The survey results allow us to assess the similarities and the differences between the approaches to measure, process, and evaluate chamber CH4 fluxes used by the different flux experts. This knowledge can help at harmonizing chamber measurement methods for CH4 fluxes and thus at identifying and eliminating sources of uncertainty for data synthesis products which combine data sets processed by various researchers. A reassessment of chamber techniques becomes particularly important in the light of an increasing use of new multigas analyzers whose high-frequency and high-accuracy CH4 concentration measurements both open new possibilities and pose new challenges in the interpretation of chamber measurements.
description: The provided files contain the archived survey questions, demographic information on the survey participants, the participants' responses to the survey questions, photos of the participants' measurement setups, and the raw data of chamber measurements that were used in the visual quality control part of the survey. A detailed overview of the provided files, their content, variable abbreviations and units can be found in Jentzschetal2024_ExpertSurveyChamberCH4Fluxes_Metadata.pdf.
DOI: 10.1594/pangaea.975993
title: Proxydata to reconstruct peak glacial-to-Heinrich-1 changes in Denmark Strait Overflow and sea water stratification in the Nordic Seas 22–15 cal ka

description: We present stable C and O isotope data and radiocarbon ages in the Nordic Seas as tracers of peak-glacial-to-Heinrich-1 changes of surface and deep-water temperature, salinity, nutrient content, ventilation, and ventilation age, now age-recalibrated by means of the 14C-plateau tuning technique. Its results compare well with ages of the NGRIP incremental age scale. Radiogenic Nd and Th/U isotopes are used to constrain the differential origins of bottom waters feeding the Denmark Strait Overflow.
DOI: 10.1594/pangaea.974107
title: Methane and carbon dioxide production from anaerobically incubated boreal peat treated with nitrogen addenda

description: This dataset reports greenhouse gas production measurements from a laboratory incubation of sphagnum and peat sourced from a boreal peatland complex (Siikaneva Bog, Finland). Shallow peat samples were extracted in bulk with a bread knife in October 2022 from a homogeneous sphagnum lawn at three locations within several meters distance. Three soil horizons were distinguished according to the position of the water table: above (0-3 cm), fluctuating (3-7 cm) and below the water table (7-20 cm). Three spatial replicates were united per layer. Subsamples from above and below the water table were amended with solutions of NaNO3 and NH4Cl at different concentrations and incubated in 120 ml airtight glass vials in a N2 atmosphere for 365+ days to investigate the effect of nitrogen addenda on greenhouse gas production. Two matching sets of samples were incubated at 4°C and 20°C. Vial containing only untreated water or the treatment solution were kept aside the samples as blanks. The headspace gas was sampled regularly and CO2 and CH4 concentrations determined by GC-FID (Shimadzu Nexis GC-2030). This dataset contains the measured headspace concentrations as well as cumulative carbon fluxes standardized by gram soil carbon. Headspaces were flushed with Nitrogen when CO2 concentrations surpassed 10 000 ppm. Cumulative fluxes were computed from concentration changes between measurements, including an estimate of the fraction of gas dissolved in the water column at each date, and losses during sampling. Additionally, carbon and nitrogen contents are reported from material that was archived before the incubation (soliTOC cube, elementar Analysensysteme / exceed rapid maxN). From the additional portions of the same archive, water was extracted with Rhizon samplers to probe pH and electric conductivity and determine dissolved organic carbon (elementar Analysensysteme / TOC-L analyzer with TNM-1 module, Shimadzu).
DOI: 10.1594/pangaea.975091
title: Scale bar errors of cold-water coral 3D reconstructions from three different setups

description: For accurate 3D photogrammetric measurements of corals under laboratory conditions, two prototypes (Azores 3D system and Barcelona 3D system) and a final setup (Coruña 3D system) were presented. These setups were designed to obtain a complete set of images of a coral in an aquarium and create accurate 3D reconstructions. A total of 24 (Azores), 177 (Barcelona) and 120 (Coruña) 3D reconstructions of cold-water corals were used to evaluate the systems. The effectiveness of the three systems was assessed by taking into account the total scale error of the 3D reconstructions. The total scale error is the difference between the input scale bar lengths and the measured distance between two-point markers. Here, we provide the total scale error from every reconstruction of each system.
DOI: 10.1594/pangaea.959036
title: Measured rate-and-state friction coefficients, with input parameters for the forward model and the best fit model parameters as obtained by an inverse modelling technique during laboratory shear experiments
DOI: 10.1594/pangaea.965377
title: Pore water data of sediment core YC22_MR_8 off Herschel island (Yukon Coast 2022)

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).
DOI: 10.1594/pangaea.941413
title: RICE ice core calcium data for the last glacial period (83-26 ka BP)

description: Roosevelt Island Climate Evolution (RICE) ice core calcium (Ca) data, measured using continuous flow analysis (CFA), covering last glacial period 83000-26000 years BP is presented here. RICE is a 764-m long ice core retrieved from Roosevelt Island, a coastal dome in the vicinity of Ross Sea, West Antarctica. The measurements were made at Centre for Ice and Climate, University of Copenhagen, Denmark in 2015 and posses annual resolution. A three-point calibration was used for the measurements.
DOI: 10.1594/pangaea.974184
title: CTD profile measurements from a glacier-fed fjord conducted close to a sensor deployment site during cruise TU19 (Nuup Kangerlua, Greenland)

description: This dataset contains temperature conductivity, turbidity and depth measurements from a CTD profile taken in a glacier-fed fjord (Nuup Kangerlua, Greenland). The profile was conducted in the vicinity of a sensor mooring that contained nitrate, dissolved silica and CTD sensors.
DOI: 10.1594/pangaea.932746
title: Benthic foraminiferal data of sediment core GeoB13731-1, East Melilla
DOI: 10.1594/pangaea.945729
title: BRITICE-CHRONO maps and GIS data of the last British-Irish Ice Sheet 31 to 15 ka, including model reconstruction, geochronometric age spreadsheet, palaeotopographies and coastline positions

description: The BRITICE-CHRONO project measured 639 new geochronometric ages that constrain the timing of advance and retreat of the last British-Irish Ice Sheet between 31,000 and 15,000 years ago, including across the North Sea. These ages (optically stimulated luminescence, radiocarbon and terrestrial cosmogenic nuclide methods) are made available in an excel spreadsheet, along with all sample and laboratory metadata and calibrations. Together with other published information, the ages were used to build an empirical ice sheet reconstruction at one thousand year time-steps. A poster-map and slideshow (PDF) of the reconstruction (31 to 15 ka) and the underlying GIS data (ArcGIS shapefiles) of ice extents (min, max and optimum) are made available here. An ice sheet model was nudged to fit these ice limits and the ensuing model-reconstruction is made available as a poster-map, slideshow (PDF) and movie (GIF) of the reconstruction (31 to 15 ka). The GIS data is also available including grounded ice extent and ice shelves, ice thickness, ice surface elevation, and ice velocity (as ArcGIS grids). From glacio-isostatic adjustment modelling we also provide digital elevation models of the palaeotopography of the British Isles and surrounding sea floors and coastline positions from 36 to 1 ka (ArcGIS grids and shapefiles). Full methods, descriptions, caveats and interpretations are available in the parent paper to this dataset: Clark. C.D. et al. (2022) Growth and retreat of the last British-Irish Ice Sheet, 31,000 to 15,000 years ago: the BRITICE-CHRONO reconstruction, Boreas.
DOI: 10.1594/pangaea.945542
title: Snow stable water isotopes of a 2 cm deep surface transect at the EastGRIP deep drilling site, summer season 2018

description: Snow samples were taken on a daily basis along a 100 m wind-parallel transect at the EastGRIP ice core deep drilling site. The snow was collected in the morning at 11 positions with 10 m spacing into three cumulative samples – each for one depth interval. The depth intervals are top 0.5 cm, top 1 cm, and top 2 cm. Each day, undisturbed snow was sampled and the exact sample location was marked to avoid sampling disturbed snow during the next sampling event. The samples were shipped frozen to the Alfred-Wegener-Institut and stored at -25 °C. Prior to measurements, the samples were melted in the sample bags at room temperature. For the measurement of the isotopic composition, a Picarro L2130-i with a high-throughput vaporizer (model A0212) was used. The measurement set-up followed the Van-Geldern protocol. Each sample was injected four times and the standard deviation is computed. We calculate the average over all the standard deviations as a measure of uncertainty. We find this average to be 0.04 permil for δ18O (with stdev 0.02) and 0.13 permil for δD (stdev 0.07). The maximum standard deviation within the data set was found to be 0.14 for δ18O and 0.48 for δD. As a measure of accuracy, the offset between the defined and the measured value of the quality check standard for each measurement run is provided. We calculate the average of this offset for the whole data set and obtain a value of 0.07 permil for δ18O (stdev 0.03) and -0.11 permil for δD (stdev 0.08). The maximum offset found within the data set was 0.12 permil for δ18O and -0.25 permil for δD.
DOI: 10.1594/pangaea.945545
title: Snow stable water isotopes of precipitation samples at the EastGRIP deep drilling site, summer season 2019

description: Precipitation and rime samples were taken after precipitation events from specific boxes to collect precipitation snow. Two white plastic boxes are placed outside the camp area 1 m above the snow surface and behind a wind shield. The snow was collected using a brush, spatula and small shovel. From each box the available snow was collected into a plastic bag and sealed and labeled. In case the snow of one box was not enough for one sample, the snow of both boxes were combined as one sample. In case not all snow was sampled, the boxes were cleared out after sampling. The samples were kept frozen and shipped frozen to the Alfred-Wegener-Institute and stored at -25 °C. Prior to measurements the samples were melted in the sample bags at room temperature. For the measurement of the isotopic composition a Picarro L2140-i was used. The measurement set-up followed the Van-Geldern Protocol. Each sample was injected four times and the standard deviation is computed. We calculate the average over all the standard deviations as a measure of uncertainty. We find this average to be 0.01 permil for δ18O (with stdev 0.01) and 0.12 permil for δD (stdev 0.2). The maximum standard deviation within the data set was found to be 0.07 for δ18O and 1.1 for δD. As a measure of accuracy the off-set between the defined and measured value of the quality check standard for each measurement run is provided. We calculate the average of this off-set for the whole data set and obtain a value of -0.07 permil for δ18O (stdev 0.02) and -0.73 permil for δD (stdev 0.09). The maximum off-set found within the data set was -0.1 permil for δ18O and -0.87 permil for δD.
DOI: 10.1594/pangaea.957619
title: Insoluble dust, ammonium, calcium, conductivity, peroxide and acid measured in firn cores in Northern Greenland in 2015: T2015-A3

description: Results from six firn cores obtained during a 426 km long northern Greenland traverse in 2015 between the NEEM and the EGRIP deep drilling stations situated on the Western and Eastern side of the Greenland ice sheet, respectively. The cores (9 to 14 m long) are analysed for chemical impurities by means of Continuous Flow Analysis (CFA); Insoluble dust, ammonium, calcium, acid, conductivity and peroxide. The data was dated by means of annual layer counting of mainly peroxide supplemented by calcium seasonal cycles and spans 18 to 53 years (±3 yrs) depending on local snow accumulation that decreases from west to east. Insoluble dust, ammonium, and calcium concentrations in the 6 firn cores overlap, and also the seasonal cycles are similar in timing and magnitude across sites, while peroxide (H2O2) and conductivity both have spatial variations. H2O2 is driven by the accumulation pattern and conductivity is likely influenced by sea salt. Data is published as part of Kjær et al. 2022, Climate of the past, https://doi.org/10.5194/cp-2021-99
DOI: 10.1594/pangaea.957620
title: Insoluble dust, ammonium, calcium, conductivity, peroxide and acid measured in firn cores in Northern Greenland in 2015: T2015-A4

description: Results from six firn cores obtained during a 426 km long northern Greenland traverse in 2015 between the NEEM and the EGRIP deep drilling stations situated on the Western and Eastern side of the Greenland ice sheet, respectively. The cores (9 to 14 m long) are analysed for chemical impurities by means of Continuous Flow Analysis (CFA); Insoluble dust, ammonium, calcium, acid, conductivity and peroxide. The data was dated by means of annual layer counting of mainly peroxide supplemented by calcium seasonal cycles and spans 18 to 53 years (±3 yrs) depending on local snow accumulation that decreases from west to east. Insoluble dust, ammonium, and calcium concentrations in the 6 firn cores overlap, and also the seasonal cycles are similar in timing and magnitude across sites, while peroxide (H2O2) and conductivity both have spatial variations. H2O2 is driven by the accumulation pattern and conductivity is likely influenced by sea salt. Data is published as part of Kjær et al. 2022, Climate of the past, https://doi.org/10.5194/cp-2021-99
DOI: 10.1594/pangaea.944857
title: Planktonic foraminifera abundances and calcite mass of sediment core MD04-2718
DOI: 10.1594/pangaea.952933
title: Firn cores obtained in Northern Greenland in 2015

description: Results from six firn cores obtained during a 426 km long northern Greenland traverse in 2015 between the NEEM and the EGRIP deep drilling stations situated on the Western and Eastern side of the Greenland ice sheet, respectively. The cores (9 to 14 m long) are analysed for chemical impurities by means of Continuous Flow Analysis (CFA); Insoluble dust, ammonium, calcium, acid, conductivity and peroxide. The data was dated by means of annual layer counting of mainly peroxide supplemented by calcium seasonal cycles and spans 18 to 53 years (±3 yrs) depending on local snow accumulation that decreases from west to east. Insoluble dust, ammonium, and calcium concentrations in the 6 firn cores overlap, and also the seasonal cycles are similar in timing and magnitude across sites, while peroxide (H2O2) and conductivity both have spatial variations. H2O2 is driven by the accumulation pattern and conductivity is likely influenced by sea salt. Data is published as part of Kjær et al. 2022, Climate of the past, https://doi.org/10.5194/cp-2021-99
DOI: 10.1594/pangaea.944799
title: Sea surface temperature record of sediment core MD04-2718
DOI: 10.1594/pangaea.944816
title: Stable oxygen and carbon isotopes in planktic foraminifera N. pachyderma s. of sediment core MD04-2718
DOI: 10.1594/pangaea.957618
title: Insoluble dust, ammonium, calcium, conductivity, peroxide and acid measured in firn cores in Northern Greenland in 2015: T2015-A2

description: Results from six firn cores obtained during a 426 km long northern Greenland traverse in 2015 between the NEEM and the EGRIP deep drilling stations situated on the Western and Eastern side of the Greenland ice sheet, respectively. The cores (9 to 14 m long) are analysed for chemical impurities by means of Continuous Flow Analysis (CFA); Insoluble dust, ammonium, calcium, acid, conductivity and peroxide. The data was dated by means of annual layer counting of mainly peroxide supplemented by calcium seasonal cycles and spans 18 to 53 years (±3 yrs) depending on local snow accumulation that decreases from west to east. Insoluble dust, ammonium, and calcium concentrations in the 6 firn cores overlap, and also the seasonal cycles are similar in timing and magnitude across sites, while peroxide (H2O2) and conductivity both have spatial variations. H2O2 is driven by the accumulation pattern and conductivity is likely influenced by sea salt. Data is published as part of Kjær et al. 2022, Climate of the past, https://doi.org/10.5194/cp-2021-99
DOI: 10.1594/pangaea.957621
title: Insoluble dust, ammonium, calcium, conductivity, peroxide and acid measured in firn cores in Northern Greenland in 2015: T2015-A5

description: Results from six firn cores obtained during a 426 km long northern Greenland traverse in 2015 between the NEEM and the EGRIP deep drilling stations situated on the Western and Eastern side of the Greenland ice sheet, respectively. The cores (9 to 14 m long) are analysed for chemical impurities by means of Continuous Flow Analysis (CFA); Insoluble dust, ammonium, calcium, acid, conductivity and peroxide. The data was dated by means of annual layer counting of mainly peroxide supplemented by calcium seasonal cycles and spans 18 to 53 years (±3 yrs) depending on local snow accumulation that decreases from west to east. Insoluble dust, ammonium, and calcium concentrations in the 6 firn cores overlap, and also the seasonal cycles are similar in timing and magnitude across sites, while peroxide (H2O2) and conductivity both have spatial variations. H2O2 is driven by the accumulation pattern and conductivity is likely influenced by sea salt. Data is published as part of Kjær et al. 2022, Climate of the past, https://doi.org/10.5194/cp-2021-99
DOI: 10.1594/pangaea.944782
title: Calcium carbonate percentage of sediment core MD04-2718
DOI: 10.1594/pangaea.944793
title: Calcium X-ray fluorescence (XRF) scanning of sediment core MD04-2718
DOI: 10.1594/pangaea.908925
title: Wave measurements (Nortec AWAC 1 Mhz ADCP) collected at the OBSEA underwater observatory during February, 2012
DOI: 10.1594/pangaea.910396
title: Methane and carbon dioxide concentrations measured during POSEIDON cruise POS527, 2018-08-28

description: A gas inlet was installed at the bow of RV Poseidon.Atmospheric gas concentrations of CH4 and CO2 were measured continuously with a Picarro G2301-f analyzer.Concentrations are given as “ppmV in dry air”.
DOI: 10.1594/pangaea.907899
title: Pore water geochemical data from Greenland margin and the Labrador Sea
DOI: 10.1594/pangaea.907904
title: Core incubation geochemical data from Greenland margin and the Labrador Sea
DOI: 10.1594/pangaea.941897
title: A refined age model and 143Nd/144Nd for the U1361A marine sediment core

description: This data set displays a refined age scale for the U1361A marine sediment core (64.41°S, 143.89°E, 3,454 m water depth), recovered from the continental rise offshore of the Wilkes Subglacial Basin, during the Integrated Ocean Drilling Program (IODP) Expedition (Escutia et al. 2011). This age scale is a refined version of the age scale published in Wilson et al. 2018. Here we use the AICC2012 ice core chronology as a reference curve in order to compare the late Pleistocene sediment core data from U1361A to the TALDICE ice core record. Specifically, we refine the existing U1361A age model through the alignment of barium/aluminium (Ba/Al) ratios from XRF-scanning7 with the EDC δD record on the AICC2012 age scale. We apply a conservative tuning strategy to align the two records, using tie points (derived by visual matching) only at the mid-points of the major glacial terminations I-V. Over the interval of interest for the present study (i.e. ~100-350 ka), the new age model for core U1361 differs by only 0 to 6 ka compared to the previous age model in which the sedimentation rate was assumed to be constant. The Nd and IBRD (ice rafted debris) and 143 Nd/144 Nd records for the U1361A published in Wilson et al. (2018) are drawn on the refined age scale.
description: 2 s.e. = internal precision (2s level) on sample measurement 2 s.d. = external reproducibility estimated from the within-session standard deviation (2s.d.) on JNdi-1 standards Over the course of the analyses, measurements of rock standard BCR-2 gave 143Nd/144Nd = 0.512640 ± 0.000016 (n=31)IBRD (ire rafted debris) and 143Nd/144Nd records of the U1361A sediment core (Wilson et al. 2018) drawn of the refined age scale tuned on the AICC2012 chronology for EDC (Bazin et al. 2013)