cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.1594/pangaea.963848
title: Diatom counts from sediment core HZM19, Holzmaar (West-Eifel Volcanic Field, Germany)

description: Diatom analyses were done following (Battarbee, 1986; Battarbee et al., 2002; doi:10.2478/s11756-019-00407-8). Including an updated list of names. The sediment core HZM19 was collected in 2019, from Holzmaar, West-Eifel Volcanic Field in Germany using a UWITEC Piston Corer. The sediment core was collected to reconstruct environmental and climate changes of Holzmaar for the last 16,000 years cal BP. Particularly in this data set we cover between 2450-2950 cal BP. An aliquot of each freeze-dried sample was processed with standard procedures (Battarbee, 1986; Battarbee et al., 2002). Only species with &gt;=5% relative abundance in at least two samples were used for further analyses. Species acronyms are listed seperately.
description: Funding information:* Georg Forster Research Fellowship for postdoctoral researchers (for the Alexander von Humboldt funding)* Central Research Development Fund (CRDF) of the University of Bremen, 04 Independent Project for Postdocs– Funding objective B
DOI: 10.1594/pangaea.963846
title: CNS analyses from sediment core HZM19, Holzmaar (West-Eifel Volcanic Field, Germany)

description: C, N and S analysed with a CNS elemental analyser (EuroEA, Eurovector). Biogenic silica was measured following the leaching method of Müller & Schneider (1993, doi:10.1016/0967-0637(93)90140-X). The sediment core HZM19 was collected in 2019, from Holzmaar, West-Eifel Volcanic Field in Germany using a UWITEC Piston Corer. The sediment core was collected to reconstruct environmental and climate changes of Holzmaar for the last 16,000 years cal BP. Particularly in this data set we cover between 2450-2950 cal BP.
description: Funding information:* Georg Forster Research Fellowship for postdoctoral researchers (for the Alexander von Humboldt funding)* Central Research Development Fund (CRDF) of the University of Bremen, 04 Independent Project for Postdocs– Funding objective B
DOI: 10.1594/pangaea.963847
title: Chronology from sediment core HZM19, Holzmaar (West-Eifel Volcanic Field, Germany)

description: Chronology is based on Birlo et al. 2023, the Age is in calibrated years Before Present. The sediment core HZM19 was collected in 2019, from Holzmaar, West-Eifel Volcanic Field in Germany using a UWITEC Piston Corer. The sediment core was collected to reconstruct environmental and climate changes of Holzmaar for the last 16,000 years cal BP. Particularly in this data set we cover between 2450-2950 cal BP.
description: Funding information:* Georg Forster Research Fellowship for postdoctoral researchers (for the Alexander von Humboldt funding)* Central Research Development Fund (CRDF) of the University of Bremen, 04 Independent Project for Postdocs– Funding objective B
DOI: 10.1594/pangaea.963849
title: Hyperspectral scanning imaging index from sediment core HZM19, Holzmaar (West-Eifel Volcanic Field, Germany)

description: Pigments measurements (RABD671 and RABD845) were made by Specim PFD-CL-65V10E linescan camera following the methods of (Butz et al., 2015, doi:10.1117/1.JRS.9.096031), at a resolution of 60 × 60 μm. Scanning methodology and index calculations can be found in (Zander et al., 2021, doi:10.1016/j.scitotenv.2020.143713). The sediment core HZM19 was collected in 2019, from Holzmaar, West-Eifel Volcanic Field in Germany using a UWITEC Piston Corer. The sediment core was collected to reconstruct environmental and climate changes of Holzmaar for the last 16,000 years cal BP. Particularly in this data set we cover between 2450-2950 cal BP.
description: Funding information:* Georg Forster Research Fellowship for postdoctoral researchers (for the Alexander von Humboldt funding)* Central Research Development Fund (CRDF) of the University of Bremen, 04 Independent Project for Postdocs - Funding objective B
DOI: 10.1594/pangaea.706743
title: (Table 3) Concentration of some compounds extracted by benzene-methanol in sediments from DSDP Hole 4-27
DOI: 10.1594/pangaea.963851
title: X-ray fluorescense (XRF) core scanning from sediment core HZM19, Holzmaar (West-Eifel Volcanic Field, Germany)

description: XRF measurements in 0.2 to 1 mm increments with an ITRAX XRF core scanner (Cox Analytics) and Cr tube (Croudance et al. 2015, doi:10.1007/978-94-017-9849-5 ). The sediment core HZM19 was collected in 2019, from Holzmaar, West-Eifel Volcanic Field in Germany using a UWITEC Piston Corer. The sediment core was collected to reconstruct environmental and climate changes of Holzmaar for the last 16,000 years cal BP. Particularly in this data set we cover between 2450-2950 cal BP.
description: Funding information:* Georg Forster Research Fellowship for postdoctoral researchers (for the Alexander von Humboldt funding)* Central Research Development Fund (CRDF) of the University of Bremen, 04 Independent Project for Postdocs - Funding objective B
DOI: 10.1594/pangaea.743873
title: (Table 2) Extractable geolipids from Cretaceous Leg 103 samples
DOI: 10.1594/pangaea.864240
title: (Table 1) n-Alkane concentrations in dried sediment, carbon preference index (CPI), and normalized C31 index of sediment core GeoB9501-4
DOI: 10.1594/pangaea.921384
title: NSO-1 biomarker ratios obtained by full scan mode
DOI: 10.1594/pangaea.921385
title: NSO-1 biomarker ratios obtained by GC-QQQ-MS analyses in MRM
DOI: 10.1594/pangaea.972149
title: Plant wax biomarkers record from sediment core PEX19-01, Lake Peixão, Serra da Estrela, Portugal

description: These data comprise a downcore record (PEX19-01) of plant wax n-alkanes (concentration and compound-specific δ2H and δ13C isotopes) from Lake Peixão (40°20'35" N, 7°36'19" W), a small alpine lake located at 1677 meters above sea level in the Serra da Estrela Mountain, Portugal. The lake covers an area of 0.02 km² with a maximum water depth of approximately 5 meters. Characterized as oligotrophic, slightly acidic, and monomictic, Lake Peixão's settings and location present an ideal setting for paleoenvironmental studies between Atlantic and Mediterranean-influenced climates. Sediment cores were collected at a depth of about 4 meters during a field campaign from June 10 to June 14, 2019, using a UWITEC© piston coring system from a floating platform, and a short core (PEX15-01C; 1.23 m long) using a UWITEC gravity coring system (see Moreno et al., 2023). According to the age model by Hernández et al., 2023, the studied section of the sediment core (upper 120 cm) spans the last 2000 years with a mean resolution of 30 ± 10 years for n-alkane samples.This study aims to reconstruct past vegetation and climate dynamics in western Iberia and to address the lack of long-term climate data. It focuses on understanding the interactions between Mediterranean and Atlantic influences on Western Iberia during key climatic periods such as the Roman Period, Early Middle Ages, Medieval Climate Anomaly, Little Ice Age, and the Industrial Era to the present day. This knowledge is crucial for predicting future climate scenarios and understanding the adaptive responses of alpine ecosystems to climatic variability.The sediment samples were collected every 2 cm, resulting in 60 samples weighing between 0.4 and 0.6 grams each. Plant-wax n-alkanes were extracted and analyzed at the BioGeoChemistry Lab, IPMA in Lisbon, Portugal. The total lipid extracts underwent various purification and analysis steps, including ultrasonic bath extraction, hydrolysis with potassium hydroxide in methanol, and separation using silica gel columns. Concentrations were measured using gas chromatography with flame ionization detection (GC-FID). Compound-specific isotope analyses (δ13C n-alk and δ2H n-alk) were conducted using gas chromatography-isotope ratio mass spectrometry (GC-IRMS) at MARUM, University of Bremen, Germany (see Santos et al., 2022).
DOI: 10.1594/pangaea.756757
title: (Figure 3a) Sedimentary n-alkane concentration of sediment core GeoB9508-5
DOI: 10.1594/pangaea.785879
title: (Table 1) Brief description, main minerals, and hydrocarbon and n-alkane contents in samples from the Rainbow Hydrothermal Field
DOI: 10.1594/pangaea.971996
title: Stable carbon and oxygen isotopes of benthic foraminifera from IODP Site 383-U1542

description: The realisation of IODP Expedition 383 DYNAPACC to the subantarctic South Pacific closed a critical gap in available sedimentary records from the pelagic Subantarctic Pacific. The sites for the first time sample the formation area of Southern Ocean Intermediate Water (SOIW) and the core region of the Antarctic Circumpolar Current (ACC) in the Pacific sector of the Southern Ocean, both of which play a critical role in the Pleistocene climate evolution. Our studies are based on samples from IODP Site U1542, which is located proximal to the Chilean continental margin in the Subantarctic Zone (SAZ) close to the Drake Passage (54°42.29' S; 75°35.77' W; ~1110 m water depth; 249 m spliced core length). We use a planktonic foraminiferal multi-species isotope/geochemistry approach, combining high-resolution stable isotope (δ18O, δ13C) time series with elemental geochemistry (Mg/Ca). We intend to reconstruct the paleophysical and -chemical characteristics of surface, subsurface, and thermocline watermasses in order to understand their long-term dynamics, their sensitivity to and interaction with changing climate forcing mechanisms throughout the last 780 kyrs, including the major climate transition of the Mid-Brunhes Epoch (MBE).
DOI: 10.1594/pangaea.971595
title: Biomarkers of sediment cores from a land – shore transect in the Teshekpuk Lake Region in Arctic Alaska, 2022

description: This dataset describes six sediment cores (12 - 219 cm length) from different landscape features in a coastal permafrost thermokarst affected landscape in the Theshekpuk Lake region in Arctic Alaska. They are located in a transect from inland to coast, to describes the transitional dynamics between terrestrial and marine permafrost and thermokarst. The cores were drilled during the Perma-X Lagoon expedition in April 2022. The three unfrozen cores from a marine (MAR, 12 cm length), an intact lagoon (LAG, 31 cm length) and a thermokarst lake (TKL, 50 cm length) site, were all sampled using a Push Corer. The three frozen cores, including upland permafrost (UPL, 203 cm length), drained thermokarst lake basin (DLB, 219 cm length) and semi-drained lagoon (SDLAG, 183 cm length) deposits, were drilled using a SIPRE Corer. For the lipid-biomarker analysis 15 subsamples were selected. In case of the shortest core (MAR) only one sample, in case of the medium length unfrozen cores (LAG, TKL) two samples and in case of the frozen cores three, respectively four samples in case of the longest core from the DLB, were selected. The measured parameters and calculated indices included the total concentration of n-alkanes [µg/gTOC], the total concentration of n-alkanols [µg/gTOC], Average chain length (ACL), Paq, Pwax, carbon preference index (CPI), and higher plant index (HPA). The data is related to the paper Organic Carbon, Mercury, and Sediment Characteristics along a land – shore transect in Arctic Alaska , Giest et al. (currently in submission).
DOI: 10.1594/pangaea.972789
title: Impact of climate change on the kelp Laminaria digitata: Biochemical and physiological raw data of a long-term experiment simulating Artic winter warming

description: Global warming affects the Arctic much faster than the rest of the globe, with the highest amplitude of temperature rise occurring during the Polar Night. To determine the stress resistance of the ecosystem-engineering kelp Laminaria digitata against Arctic winter warming, non-meristematic discs of adult sporophytes from Porsangerfjorden (Finnmark, Norway) were kept in total darkness at 0°C and 5°C over a period of three months. The maximum photosynthetic quantum yield of photosystem II (Fv/Fm; Imaging-PAM, Walz GmbH Mess- und Regeltechnik, Effeltrich, Germany) was monitored once a week. For monitoring of potential growth, the size (area) of the algal discs was photographed every two weeks and analyzed with ImageJ (Version 1.52a). Every four weeks, subsamples for monitoring the dry weight and for the biochemical analyses were taken. Laminarin content was determined following via enzymatic digestion. C:N ratio was analyzed with an Elementar Analyzer. Mannitol concentration was analyzed using a HPLC. Absolut pigment concentrations were also analyzed using a HPLC and pool sizes, the de-epoxidation state of the xanthophyll cycle (DPS), and the ratios calculated afterwards.
description: Treatment details ----------------------------Laminaria digitata samples from the Porsangerfjorden, Finnmark, Norway0°C and 5°C, total darkness for 3 monthsw0 = week 0 (start)w4 = week 4w8 = week 8w12 = week 12 (end)set-up:2-L aerated Kautex bottles, 1/40 PES, medium changed 2x/weekSample: These values are used to differentiate multiple similar samples within the same replicate. They do not denote a relationship between weeks. E.g. Sample #3 from week 0 (w0) of Replicate 2, is not necessarily a sample of the same organism for Sample #3 from week 1 (w1) of Replicate 2. Meaning that Samples should not be taken as time series of measures of the same organism through time.
DOI: 10.15468/dl.5hzcfs
title: Occurrence Download

description: A dataset containing 1757 species occurrences available in GBIF matching the query:
{
 "and" : [
 "HasGeospatialIssue is false",
 "HasCoordinate is true",
 "TaxonKey is one of (Rana pretiosa Baird & Girard, 1853)"
 ]
}

 The dataset includes 1757 records from 33 constituent datasets; see https://api.gbif.org/v1/occurrence/download/0003846-250415084134356/datasets/export for details.
 
Data from some individual datasets included in this download may be licensed under less restrictive terms.
DOI: 10.1594/pangaea.918260
title: Latest Pleistocene-Holocene n-alkane data from an alpine lake, Laguna de Río Seco, in southern Spain

description: This dataset contains the n-alkane data from a sedimentary record of an alpine lake (Laguna de Río Seco -LdRS-) located at 3020 masl in Sierra Nevada (southern Spain). This dataset includes the concentrations of the n-alkanes ranging from the C19 to the C35 chain lengths and the hydrogen isotopic composition of the C23, C25, C27, C29, C31, and C33 ones. Different indices have also been calculated to summarise 1) the n-alkane chain lengths: the average chain length (ACL), the carbon preference index (CPI), and the portion aquatic index (Paq), and 2) the hydrogen isotopic composition of the terrestrial n-alkanes (δDwax=δDC29 + δDC31), aquatic n-alkanes (δDaq= δDC23 + δDC25), and their difference ΔDwax-aq(δDwax-δDaq).The n-alkanes were analysed using a GC-FID (Shimadzu 2010) and a GC-MS (Shimadzu QP2010-Plus Mass Spectrometer interfaced with a Shimadzu 2010 GC).Hydrogen isotopic composition of sedimentary n-alkanes was measured with GC-IRMS using a GC-thermal conversion-IRMS system consisting of a HP 6890 GC connected to a Finnigan MAT delta Plus XL mass spectrometer.
DOI: 10.1594/pangaea.706742
title: (Table 3) Concentration of some compounds extracted by benzene-methanol in sediments from DSDP Hole 4-26
DOI: 10.1594/pangaea.971718
title: Concentration of n-alkanes and hydrogen isotopic compositions from modern wetland plants, soil and surface water of Nisí fen and Tenaghi Philippon

description: This data supporting the study Leaf wax n-alkane distribution and hydrogen isotopic fractionation in fen plant communities of two Mediterranean wetlands (Tenaghi Philippon, Nisí fen - Greece). A total of 452 samples; of these, the majority (229) were samples of fully developed leaves, collected from the apical, sun exposed sections of each plant. Similarly, 161 samples were collected from the base of the main stem (except for N. alba). All samples were collected during midday (ca 10:00 to 17:00), with mean air temperatures of 24-28°C (Nisí) and 28-29°C (TP) in summer, and 21-24°C (Nisí) and 26°C (TP) in spring in Tenaghi Philippon (TP) peatland (NE Greece) and Nisí wetland (NW Greece). Understanding of the n-alkane environmental controls and 2H-fractionation mechanisms of Mediterranean helophytic communities, as well as ascertaining the 2H-composition of their source water and its relation to the 2H-composition of precipitation. All leaf and lower stem samples come from different mature individuals of a species, sampled in close proximity, and complemented by a total of 47 soil samples collected at ca. 20 cm depth within each sampling station, from patches not directly exposed to sunlight to avoid potential 2H-fractionation bias due to intense soil water evaporation. Additionally, 10 surface water samples were collected from swamp areas in proximity of the sampling stations at both sites. δ2H values of the 10 surface water samples were obtained using LGR LWIA-24d. Delta values are given as permil deviation from VSMOW (±1‰). Leaf, stem, and soil water was extracted through cryogenic vacuum distillation and its isotopic composition was measured using a TC/EA-MS via a Conflo IV interface; expressed as permil deviation from VSMOW and the long-term external precision was found to be ±0.8‰ (standard deviation). The n-alkanes of leaf, stem and soil samples were extracted via ASE, separated by increasing polarity, analysed via GC-MS, and quantified using an external standard. The n-alkane δ2H values of leaf and stem samples were determined using GC-irMSThe overall analytical uncertainty (pooled sample size weighted standard deviation) was found to be ±1.7‰.
DOI: 10.1594/pangaea.745616
title: Bulk and molecular proxies of sediment core GeoB6518-1

description: A 20 kyr long sediment sequence from the Congo deep sea fan (core GeoB 6518-1), one of the world's largest deep sea river fans, has been analysed for bulk and molecular proxies in order to reconstruct the marine, soil and plant organic carbon (OC) contributions to these sediments since the last glacial maximum. The bulk proxies applied, C/N ratio and d13Corg, ranged from 10 to 12.5 and from -24.5 to -21 per mill VPDB, respectively. As molecular proxies, concentrations of marine derived alkenones and terrestrial derived odd-numbered n-alkanes were used, which varied between 0.2 and 4 µg/g dry weight sediment. In addition, the branched vs. isoprenoid tetraether (BIT) index, a proxy for soil organic matter input, was used, which varied from 0.3 to 0.5 in this core.Application of binary mixing models, based on the different individual proxies, showed estimates for terrestrial OC input varying by up to 50% due to the heterogeneous nature of the OC. Application of a three end-member mixing model using the d13Corg content, the C/N ratio and the BIT index, enabled the distinction of soil and plant organic matter as separate contributors to the sedimentary OC pool. The results show that marine OC accounts for 20% to 40% of the total OC present in the deep sea fan sediments over the last 20 kyr and that soil OC accounts for about half (45% on average) of the OC present. This suggests that soil OC represents the majority of the terrestrial OC delivered to the fan sediments.Accumulation rates of the plant and soil OC fractions over the last 20 kyr varied by a factor of up to 5, and are strongly related to sediment accumulation rates. They showed an increase starting at ca. 17 kyr BP, a decline during the Younger Dryas, peak values during the early Holocene and lower values in the late Holocene. This pattern matches with reconstructions of past central African humidity and Congo River discharge from the same core and revealed that central African precipitation patterns exert a dominant control on terrestrial OC deposition in the Congo deep sea fan. Marine OC accumulation rates are only weakly related to sediment accumulation rates and vary only little over time compared to the terrigenous fractions. These variations are likely a result of enhanced preservation during times of higher sedimentation rates and of relative small fluctuations in primary production due to wind-driven upwelling.
description: See also Schefuss et al. (2005) dataset: doi:10.1594/PANGAEA.738200
description: Supplement to: Weijers, Johan W H; Schouten, Stefan; Schefuß, Enno; Schneider, Ralph R; Sinninghe Damsté, Jaap S (2009): Disentangling marine, soil and plant organic carbon contributions to continental margin sediments: A multi-proxy approach in a 20,000 year sediment record from the Congo deep-sea fan. Geochimica et Cosmochimica Acta, 73(1), 119-132
DOI: 10.1594/pangaea.760319
title: (Table S1) Lipids of sediment core ABC26
DOI: 10.1594/pangaea.965927
title: Elemental pigment (hyperspectral imaging) data of the varved sediment record (HZM19) from Holzmaar, Germany

description: Hyperspectral image (HSI) scanning of the composite record from Holzmaar (HZM19) was measured using a Specim PFD-CL-65-V10 E line scan camera (University of Bern, Switzerland). Data were processed using the ENVI software following the workflow of Butz et al. (2015, doi10.1117/1.JRS.9.096031): data were white-corrected, masked for cracks in the sediment surface and Relative Absorption Band Depths (RABDs) were computed for 2mm wide subsets. RABD671 (band depths from 640 to 702 nm) for Total Chloropigments-a (TChl-a), RABD845 (790 - 900 nm) for Bacteriopheopigments-a (Bphe-a), and RABD620 (600 - 640 nm) for Phycocyanin (PhyCy). To translate HSI indices into absolute concentrations, a pigment extraction was performed at the University of Bern using 23 samples covering the full range of RABD671 and RABD845 index values. Ca 1 g of wet sediment was treated with 100 % acetone following the method of Lami et al. (1994, doi:10.1007/BF00684032) and extractions were measured using a Shimadzu UV-1800 spectrophotometer to obtain bulk concentrations of TChl-a and Bphe-a in µg/g dry sediment using a molar extinction coefficient for TChl-a and Bphe-a. A proxy-proxy calibration was carried out using an ordinary least square regression. After all, only 1.42 % and 0.77 % of datapoints are outside of the calibration ranges for Chl-a (calibration range: 12.75 – 1202.68 µg/g, intercept = -4799.52, slope= 4756,45, r² = 0.8, p-val = 0.00, RMSEP 10-fold = 169.03, RMSEP % = 14.05) and Bphe-a (calibration range 0.38 – 345.12 µg/g, intercept = -1295,8, slope= 1319,7, r² = 0.94, p-val = 0.00, RMSEP 10-fold = 25.26, RMSEP % = 7.32). Ages refer to Birlo et al. (2023) and the related dataset is Model D available via doi:10.1594/PANGAEA.949292.