cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.1594/pangaea.971277
title: Biogeochemical proxies of the sediment short core EN18232-1, Lake Khamra, Siberia

description: This data set is an extension to the previously published data in a bundled publication (Stieg et al., 2024a) from the Russian Lake Khamra (59.99°N, 112.98°E, 340 m a.s.l.), located in eastern Siberia in SW Yakutia. The short core (EN18232-1) was retrieved in summer 2018 and subsampled in 2021 in 39 continuous 1 cm increments covering the last 220 years (ca. 2015-1790 CE). Detailed information about the age-depth model of the short core EN18232-1 can be found in the research paper (Stieg et al., 2024b). The data contains total organic carbon (TOC) and total nitrogen (TN) content of all 39 samples from the short core EN18232-1. Freeze-dried aliquots were ground to obtain a homogeneous material. All measurements were carried out at the BioGeoChemistry Lab at AWI Potsdam. TOC was analysed by using an Elementar soli TOC cube, whereas TN was quantified by an Elementar rapid MAX N exceed. The measurement accuracy was 0.1 % for both devices. We computed the total carbon (TC) by the sum of TOC and the total inorganic carbon (TIC), available in a previous published data set (Stieg et al., 2024c (TIC)). Furthermore, we calculated the TOC/TN atomic ratio by multiplying its mass ratio by 1.167, which is the ratio of the atomic weights of nitrogen and carbon (Meyers and Teranes, 2001). Additionally, we calculated organic carbon accumulation rates (OCARs, g m-2 a-1) by dividing TOC by 100, multiplying it by the mass accumulation rate (MAR, available in Stieg et al., 2024d (Mercury)), and then converting it by further multiplication with a factor of 10,000 to g m-2 a-1 unit. Carbon and nitrogen isotopes (δ13C,δ15N) were determined using a ThermoFisher Scientific Delta‐V‐Advantage gas‐mass spectrometer equipped with a FLASH elemental analyser EA 2000 and a CONFLO IV gas‐mixing system and an MA200R autosampler system at ISOLAB of AWI Potsdam. We used freeze-dried and milled sample material and additionally removed inorganic carbon by a hydrochloric acid treatment (HCl, 1.3 mol L-1) for carbon isotopes. Isotope ratios are given relative to laboratory standards of known isotopic compositions relative to the Vienna Pee Dee Belemnite (VPDB) reference standard for carbon and to the standard atmospheric nitrogen ratio (air) for nitrogen. Results are given as delta notation (δ13C, δ15N) in per mill (‰), with 1σ standard error better than ± 0.15 ‰.
DOI: 10.1594/pangaea.971278
title: Diatom silicon isotope record of the sediment short core EN18232-1, Lake Khamra, Siberia

description: This data set is an extension to the previously published data in a bundled publication (Stieg et al., 2024a) from the Russian Lake Khamra (59.99°N, 112.98°E, 340 m a.s.l.), located in eastern Siberia in SW Yakutia. The short core (EN18232-1) was retrieved in summer 2018 and subsampled in 2021 in 39 continuous 1 cm increments covering the last 220 years (ca. 2015-1790 CE). Detailed information about the age-depth model of the short core EN18232-1 can be found in the research paper (Stieg et al., 2024b). We provide diatom silicon isotope values of all 39 samples of the short core EN18232-1, determined from the same aliquots as the diatom oxygen isotope measurements published in an earlier data set (Stieg et al., 2024c). Details of the methods used can be found in Stieg et al. (in process). In general, the laser fluorination method was applied using bromine pentafluoride (BrF5) as a reagent. In several steps the silicon is separated and trapped as silicon tetrafluoride (SiF4) for the subsequent silicon isotope analysis (Chapligin et al., 2010; Maier et al., 2013). The samples were measured on a MAT 252 IRMS at AWI Bremerhaven against a reference gas with known isotopic composition, calibrated to the reference quartz standard NBS-28. The results are expressed as delta notation δ30Si (30Si / 28Si) in per mill (‰). Analytical precision was better than 0.07 ‰ (1σ of δ30Si). The dataset includes a weighted mean value for each sample, the standard deviation, and the number of replicates.
DOI: 10.1594/pangaea.981155
title: Age-depth models for various sites on the Peru continental margin

description: This dataset provides age-depth relationships and age models for sites at the Peru continental margin, based on various radiometric, biostratigraphic and lithostratigraphic data. In sping 2002 ODP Leg 201 revisited sites that were previously drilled during ODP Leg 112 in 1986, we combined data from both expeditions. Except for some 14C data from Leg 201 samples, most data are bio-or lithostratigraphic data or stable isotope data that provide only relatively crude minimum and maximum age estimates. Between the four ODP Leg 201 sites the number of data points and the data quality varies considerably. During SONNE Cruise SO147 several gravity cores and Multicores were dated via 14C and 210Pb measurements. While the 14C data provide relatively precise ages, the 210Pb data only provide minimum and maximum ages. We compiled these data to estimate microbial carbon turnover via sulfate reduction, those data are findable at doi:10.1594/PANGAEA.981125 and doi:10.1594/PANGAEA.981124.
description: File descriptions: This file contains six worksheets1) Site data with site numbers, positions and water depths of all sites2) Age data of sites that were sampled during SONNE expedition SO147 and a generalized age-depth for these sites.3-6) Age data of sites that were sampled during ODP Leg 201. These sites were previously drilled by ODP Leg 112, we added the age-depth data from this expedition to our compilation as well. The bio- and lithostratigraphic data provide only age ranges, not definitive dates like radiometric measurements. For the age models presented below the age data on the same page we used the radiometric data as tie points and the stratigraphic age ranges as boundaries. We then tried to fit regressions through the data. As there are hiatuses and/or drastic changes in sedimentation rates in these cores, different regressions were necessary for different parts of the core.
DOI: 10.1594/pangaea.981124
title: Biological sulfate reduction rate measurements in cores from Peru continental margin of RV SONNE cruise SO147

description: This dataset provides sulfate reduction rate data, measured with radiotracer incubations. Samples originate from the Peru continental margin, taken during SONNE Cruise SO147 in May-July 2000. Sediment samples from the uppermost ca. 20 cm were taken with a Multicorer (MUC), deeper samples down to ca. 4 m with a gravity corer (GC). Radiotracer incubations were carried out on board, incubation lasted 24 hrs at approximate in-situ temperature (4°-14°C). After termination of the incubations, the samples were sent back to MPI Bremen for quantification of SRR, using the single-step hot chromium distillation of Fossing & Jørgensen (1989, doi:10.1007/BF00002889)
DOI: 10.1594/pangaea.963671
title: Sea ice lead fractions from SAR-derived sea ice divergence in the Transpolar Drift during MOSAiC 2019/2020

description: Leads and fractures in sea ice play a crucial role in the heat and gas exchange between the ocean and the atmosphere, impacting atmospheric, ecological, and oceanic processes. The precise knowledge of the aerial coverage, location, and formation history of leads is thus of great importance for polar research. Leads result from sea ice deformation processes. The breaking of the sea ice, followed by divergent ice motion, forms leads. Since the magnitude of divergence is directly proportional to the lead width, divergence is a powerful indicator of the location and width of leads. Divergence derived from satellite synthetic-aperture radar (SAR) data provides this information independent of the presence of clouds. We present here lead fractions from daily divergence fields in the Transpolar Drift along the drift of the Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition in 2019/2020. The lead fractions have a spatial resolution of 700 m and are based on divergence from Sentinel-1 imagery with an original spatial resolution of 50 m ( doi:10.1594/PANGAEA.958449). Typically, the time between two scenes was one day, with a few exceptions of 2-3 days, and the size of the scenes was on average 200 x 200 km. Lead fractions are available from 7 October 2019 to 14 January 2020 and from 15 March 2020 to 1 June 2020. Lead fractions are regularly gridded in Polar Stereographic North projection (latitude of true scale: 70°N, center longitude: 45°W) within a bounding box corresponding to 180°/60°N: -3314693.24, -3314693.24, 3314693.24, 3314693.24. Divergence alone only detects leads when they form or continue to open. To determine if a lead is closed, opened further, or stayed open, we use the divergence and convergence fields of subsequent dates and accumulate them after adjusting lead fractions from different dates to a common location using sea ice drift data. With this dataset, the data user can study (accumulated) lead fractions (adjusted to a common location) for the last 10 time instances. The data user can choose the age of the leads (typically 1-11 days) they wish to include in their analysis. In addition, the user can understand when and where a lead has formed or closed. We evaluate the accumulated divergence-derived lead fractions against existing lead products along the MOSAiC drift track (von Albedyll, et al, in review).
DOI: 10.1594/pangaea.965913
title: Abundance of the main protist groups in a subset of microscopy samples from leg 3 of the MOSAiC campaign

description: The data sets originates from the weekly sampling events (MOSAiC time series) during the MOSAiC campaign. Water samples from the CTD/Rosette were taken and fixed in Hexamin- buffered Formalin. 50ml subsamples were counted using the Utermöhl method. Counts were carried out with a Zeiss inverted microscope. The data set comprises bulk parameters with cell abundances (as cells/l) for the most abundant protist groups. In addition cell numbers for the toxic pennate diatom are provided separately
description: The data file comprises a subset of count data from MOSAiC leg 3. A summary file provides cell totals for the main plankton groups. In addition, individual data for one pennate diatom genus (Pseudo-nitzschia) is also provided. The latter is a subset of the bulk data for pennate diatoms. The values are also included in the bulk data file. The data are used for a manuscript Hoppe et al. (submitted).
DOI: 10.1594/pangaea.941356
title: Brightness temperatures of the HATPRO microwave radiometer onboard the Polarstern during the MOSAiC expedition

description: The data set contains daily files of atmospheric radiation measured during zenith (mwr00) and boundary layer (mwrBL00) mode by the HATPRO microwave radiometer (see Rose et al., 2005) onboard the Polarstern during cruise PS122 (MOSAiC expedition). The data covers the range October 2019 to October 2020. The atmospheric radiation measurements are given as brightness temperatures in seven K band (22.24 - 31.4 GHz) and seven V band (51.26 - 58 GHz) channels. The elevation scans have been perfomed approximately every 30 minutes while zenith measurements (elevation angle at 90 degrees) fill the remaining time. The brightness temperatures are provided for all available times so that it is up to the user to decide whether or not to use the values if quality flags are set. Additionally included are temperature, pressure and humidity measurements at the instrument location as well as quality flags characterizing the instrument and retrieval performance.
DOI: 10.1594/pangaea.961766
title: GPS position of SIMBA buoy (FMI02) during 2012/2013

description: The Snow and Ice Mass Balance Array (SIMBA) is a thermistor string type IMB (Jackson et al., 2013) that measures the environment temperature SIMBA-ET and temperature change (SIMBA-HT) after an identical heating element is applied to each sensor. This SIMBA (FMI02) was deployed in the high Arctic during the Polarstern Arctic cruise (ARK-XXVII/3) on 22, September 2012. The SIMBA thermistor chain is 4.8 m long and equipped with 240 thermistors at 0.02 m spacing. Snow depth and ice thickness were derived manually by investigating the SIMBA_ET vertical temperature profiles. This SIMBA was deployed on 22 Sep 2012 at 15:15 UTC. The initial position was Latitude: 88.81287 N Longitude: 57.53883 E. The initial ice thickness was 1.44 m; Freeboard was 0.21 m and the snow depth was 0.03 m. This dataset provides SIMBA GPS position.
DOI: 10.1594/pangaea.963736
title: Sea ice lead fractions from multiple sensors in the Transpolar Drift during MOSAiC 2019/2020

description: Divergent sea ice motion breaks the ice and opens fractures and leads. Depending on the air temperature, those open-water areas can quickly refreeze. The open water or thin ice in leads play a crucial role in the heat and gas exchange between the ocean and the atmosphere, impacting atmospheric, ecological, and oceanic processes. Leads can be detected from space, using different types of instruments, e.g., thermal infrared, passive microwave, active microwave, or optical sensors. The retrieval methods have different sensitivities, especially concerning the minimum lead width and the maximum ice thickness, different spatial resolutions, and different limits. We presented a time series of lead fractions from different lead products (Oct 2019 - May 2020) along the drift of the Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition in the Transpolar Drift. We compared 7 different lead products based on 1. accumulated divergence derived from SAR images, 2. divergence in linear kinematic features, 3. classified SAR data, 4. thermal infrared data from MODIS, 5. passive microwave data from AMSR-2, 6. radar altimetry from CryoSat-2 (lead fractions and total lead count), and 7. thermal infrared data from helicopter surveys. We extracted daily lead fractions in a circle with a radius of 50 km along the drift of MOSAiC. Data is available from 5 October 2019 to 15 May 2020 with shorter time series for some of the sensors. We found that the mean lead fractions varied by 1 magnitude across different lead products due to different physical lead and sea ice properties observed by the sensors and methodological factors such as spatial resolution. Thus, the choice of lead product should align with the specific application. Each file contains time and lead fraction for a circular area (radius 50 km) around the MOSAiC position of the particular time stamp. The thermal infrared data from helicopter surveys are available from doi:10.1594/PANGAEA.951569.
DOI: 10.1594/pangaea.963328
title: Water temperature recorded at the Luminao reef flat, Guam, in 2014-2015

description: This dataset provides water temperature measurements at the Luminao reef flat, Guam, in 2014 to 2015. They were conducted by the Raymundo Lab (University of Guam, Marine Laboratory), using an in situ mounted temperature logger that logged with an hourly resolution. They provide background temperature conditions at the native reef site of the Pocillopora acuta mother colonies' thermal acclimation study. Diurnal temperature characteristics are provided as daily minimum, maximum, and mean temperature values including the standard deviation around mean temperature.
DOI: 10.1594/pangaea.963327
title: Live physiology and tissue biochemistry assessment in Pocillopora acuta after 6 years under two distinct (ambient minimum winter and future warming) temperature regimes

description: In July 2015 specimens of the coral Pocillopora acuta have been sampled at the reef flat Luminao, Guam, at 1-2 m water depth. Larvae released from the mother colonies were collected and then allowed to settle and grow under two different temperatures (elevated 31°C and ambient 29°C). Surviving recruits from 31°C and 26°C were maintained either under the same elevated temperature of 31°C or under ambient winter temperatures of 26°C for six years, respectively, before assessment of their performance under the respective maintenance temperature. This allowed us to assess long-term trade-offs in coral performance specifically, as a response to living under temperature conditions exceeding their natural long-term maximum summer monthly mean temperature.
DOI: 10.1594/pangaea.973180
title: Coenzyme A thioester in the digestive system of Antarctic krill, Euphausia superba, sampled in January, March and May

description: Antarctic krill, Euphausia superba, is a key species in the Southern Ocean with an immense biomass. Ongoing climate change affects their food availability, habitat and survivability. Therefore, markers documenting changes in this species are important to monitor and discover future issues, also because krill-derived products are manufactured for human consumption. Several studies have focused on the composition of krill-derived lipids. However, they may be a potential in other metabolites to serve as tracers identifying shifts in the Antarctic environment. Krill was caught with a continuous krill pumping system in May of 2021 in the Bransfield Strait and in January and March of 2022 at the South Orkney Islands aboard the commercial krill fishing vessel Antarctic Endurance. The stomach, digestive gland and hind gut were dissected and analysed individually. Samples were initially extracted by bead-beating, with individual subsequent extraction steps adjusted for the different metabolic classes. Coenzyme A thioesters from the digestive system of Antarctic krill, Euphausia superba, were measured in bead-beater extracts resolved in water and filtered. Measurement was performed with liquid chromatography - high-resolution mass spectrometry on an Orbitrap mass spectrometer. Identification of coenzyme A thioesters was based on standards and characteristic fragments in MS2 experiments in positive electrospray ionization mode as well as on the high-resolution masses acquired. Using the high-resolution masses, sum formulas were assigned. The second row displays CoAs identify with standards (bold) or suggestions for possible CoAs, oftentimes neglecting branches or other possible modifications.
DOI: 10.1594/pangaea.973181
title: Free amino acids in the digestive system of Antarctic krill, Euphausia superba, sampled in January, March and May

description: Antarctic krill, Euphausia superba, is a key species in the Southern Ocean with an immense biomass. Ongoing climate change affects their food availability, habitat and survivability. Therefore, markers documenting changes in this species are important to monitor and discover future issues, also because krill-derived products are manufactured for human consumption. Several studies have focused on the composition of krill-derived lipids. However, they may be a potential in other metabolites to serve as tracers identifying shifts in the Antarctic environment. Krill was caught with a continuous krill pumping system in May of 2021 in the Bransfield Strait and in January and March of 2022 at the South Orkney Islands aboard the commercial krill fishing vessel Antarctic Endurance. The stomach, digestive gland and hind gut were dissected and analysed individually. Samples were initially extracted by bead-beating, with individual subsequent extraction steps adjusted for the different metabolic classes. Free amino acids from the digestive system of Antarctic krill, Euphausia superba, were measured in derivatised bead-beater extracts. Measurement of methoxycarbonyl esters was performed with gas chromatography - mass spectrometry. Identification of amino acids was based on standards.
DOI: 10.1594/pangaea.973182
title: Protein-bound amino acids in the digestive system of Antarctic krill, Euphausia superba, sampled in January, March and May

description: Antarctic krill, Euphausia superba, is a key species in the Southern Ocean with an immense biomass. Ongoing climate change affects their food availability, habitat and survivability. Therefore, markers documenting changes in this species are important to monitor and discover future issues, also because krill-derived products are manufactured for human consumption. Several studies have focused on the composition of krill-derived lipids. However, they may be a potential in other metabolites to serve as tracers identifying shifts in the Antarctic environment. Krill was caught with a continuous krill pumping system in May of 2021 in the Bransfield Strait and in January and March of 2022 at the South Orkney Islands aboard the commercial krill fishing vessel Antarctic Endurance. The stomach, digestive gland and hind gut were dissected and analysed individually. Samples were initially extracted by bead-beating, with individual subsequent extraction steps adjusted for the different metabolic classes. Protein-bound amino acids from the digestive system of Antarctic krill, Euphausia superba, were measured in hydrolysed and derivatised bead-beater extracts. Measurement of methoxycarbonyl esters was performed with gas chromatography - mass spectrometry. Identification of amino acids was based on standards.
DOI: 10.1594/pangaea.973183
title: B vitamins in the digestive system of Antarctic krill, Euphausia superba, sampled in January, March and May

description: Antarctic krill, Euphausia superba, is a key species in the Southern Ocean with an immense biomass. Ongoing climate change affects their food availability, habitat and survivability. Therefore, markers documenting changes in this species are important to monitor and discover future issues, also because krill-derived products are manufactured for human consumption. Several studies have focused on the composition of krill-derived lipids. However, they may be a potential in other metabolites to serve as tracers identifying shifts in the Antarctic environment. Krill was caught with a continuous krill pumping system in May of 2021 in the Bransfield Strait and in January and March of 2022 at the South Orkney Islands aboard the commercial krill fishing vessel Antarctic Endurance. The stomach, digestive gland and hind gut were dissected and analysed individually. Samples were initially extracted by bead-beating, with individual subsequent extraction steps adjusted for the different metabolic classes. B vitamins from the digestive system of Antarctic krill, Euphausia superba, were measured in bead-beater extracts resolved in water and filtered. Measurement was performed with liquid chromatography - mass spectrometry on an TSQ mass spectrometer. Identification of B vitamins was based on standards.
DOI: 10.1594/pangaea.973184
title: Isoprenoid quinones in the digestive system of Antarctic krill, Euphausia superba, sampled in January, March and May

description: Antarctic krill, Euphausia superba, is a key species in the Southern Ocean with an immense biomass. Ongoing climate change affects their food availability, habitat and survivability. Therefore, markers documenting changes in this species are important to monitor and discover future issues, also because krill-derived products are manufactured for human consumption. Several studies have focused on the composition of krill-derived lipids. However, they may be a potential in other metabolites to serve as tracers identifying shifts in the Antarctic environment.Krill was caught with a continuous krill pumping system in May of 2021 in the Bransfield Strait and in January and March of 2022 at the South Orkney Islands aboard the commercial krill fishing vessel Antarctic Endurance. The stomach, digestive gland and hind gut were dissected and analysed individually. Samples were initially extracted by bead-beating, with individual subsequent extraction steps adjusted for the different metabolic classes.Isoprenoid quinones from the digestive system of Antarctic krill, Euphausia superba, were measured after liquid-liquid extraction of bead-beater extracts. Measurement was performed with liquid chromatography - high-resolution mass spectrometry on an Orbitrap mass spectrometer. Identification of quinones was based on characteristic fragments in MS2 experiments in positive electrospray ionization mode.