PANGAEA_993007 Dissolved Methane release from the western margin of the Greenland Ice Sheet (2021 - 2023) Hatton, Jade Elizabeth; Stehrer-Polášková, Anna; Pika, Philip; Garnett, Mark H; Klimova, Petra; Wentzel, Lia; Jakub, Zarsky; Arndt, Sandra; Alun, Hubbard; Jakub, Trubac; Yde, Jacob; Jon, Hawkings; Eva, Doting; Jack, Murphy; Guillaume, Lamarche-Gagnon; Wadham, Jemma; Sarah, Sapper; Christiansen, Jesper Riis; Christian, Jorgensen; Stibal, Marek Dissolved Methane release from the western margin of the Greenland Ice Sheet (2021 - 2023) 2026-03-30 PANGAEA Dataset https://doi.pangaea.de/10.1594/PANGAEA.993007 Earth Science Event label DATE/TIME Date/Time local LATITUDE LONGITUDE pH Conductivity Oxygen Methane, dissolved Activity of radiocarbon in percent of modern carbon Activity of radiocarbon in percent of modern carbon, standard deviation Age, dated, range, minimum Age, dated, range, maximum δ13C, methane, dissolved δ Deuterium, methane geoscientificInformation dissolved methane glacial melt Glacial release Greenland ice sheet Holocene climate MARCH4G_2021 MARCH4G_2021_CW4a_Chem MARCH4G_2021_CW4a_GHG-a MARCH4G_2021_CW4a_GHG-b MARCH4G_2021_CW4a_GHG-c MARCH4G_2021_CW5_Chem MARCH4G_2021_CW5_GHG MARCH4G_2021_NW1_Chem MARCH4G_2021_NW1_GHG MARCH4G_2021_NW2_Chem MARCH4G_2021_NW2_GHG MARCH4G_2021_SW3a_Chem_a MARCH4G_2021_SW3a_GHG_a MARCH4G_2021_SW3a_GHG_b MARCH4G_2021_SW3a_GHG_c MARCH4G_2021_SW3a_GHG_d MARCH4G_2021_SW4_14C MARCH4G_2021_SW4_Chem MARCH4G_2021_SW4_GHG MARCH4G_2021_SW5a_Chem MARCH4G_2021_SW5a_GHG MARCH4G_2021_SW5b_14C MARCH4G_2021_SW5b_Chem MARCH4G_2021_SW5b_GHG MARCH4G_2021_SW5c_Chem MARCH4G_2021_SW5c_GHG MARCH4G_2021_SW6a_Chem MARCH4G_2021_SW6a_GHG MARCH4G_2021_SW7_GHG-a MARCH4G_2021_SW7_GHG-b MARCH4G_2021_SW7_GHG-c MARCH4G_2022 MARCH4G_2022_CW1_Chem MARCH4G_2022_CW1_GHG MARCH4G_2022_CW2_Chem MARCH4G_2022_CW2_GHG MARCH4G_2022_CW3_Chem MARCH4G_2022_CW3_GHG MARCH4G_2022_CW4c_Chem MARCH4G_2022_CW4c_GHG MARCH4G_2022_CW6_Chem MARCH4G_2022_CW6_GHG MARCH4G_2022_CW7_Chem MARCH4G_2022_CW7_GHG MARCH4G_2022_NW3_14C MARCH4G_2022_NW3_Chem MARCH4G_2022_NW3_GHG_a MARCH4G_2022_NW3_GHG_b MARCH4G_2022_NW4_14C MARCH4G_2022_NW4_Chem MARCH4G_2022_NW4_GHG_a MARCH4G_2022_NW4_GHG_b MARCH4G_2022_SW1_Chem MARCH4G_2022_SW1_GHG MARCH4G_2022_SW10_Chem MARCH4G_2022_SW10_GHG MARCH4G_2022_SW11_Chem MARCH4G_2022_SW11_GHG MARCH4G_2022_SW12_Chem MARCH4G_2022_SW12_GHG-a MARCH4G_2022_SW12_GHG-b MARCH4G_2022_SW12_GHG-c MARCH4G_2022_SW13_Chem MARCH4G_2022_SW13_GHG MARCH4G_2022_SW14a_Chem MARCH4G_2022_SW14a_GHG MARCH4G_2022_SW14b_GHG MARCH4G_2022_SW15_Chem MARCH4G_2022_SW15_GHG MARCH4G_2022_SW2_Chem MARCH4G_2022_SW2_GHG MARCH4G_2022_SW3a_Chem MARCH4G_2022_SW3a_GHG MARCH4G_2022_SW3b_14C MARCH4G_2022_SW3b_Chem MARCH4G_2022_SW3b_GHG MARCH4G_2022_SW3c_GHG-a MARCH4G_2022_SW3c_GHG-b MARCH4G_2022_SW3d_Chem MARCH4G_2022_SW3d_GHG MARCH4G_2022_SW3e_Chem MARCH4G_2022_SW3e_GHG MARCH4G_2022_SW5d_Chem MARCH4G_2022_SW5d_GHG MARCH4G_2022_SW6c_Chem MARCH4G_2022_SW6c_GHG MARCH4G_2022_SW8_Chem MARCH4G_2022_SW8_GHG MARCH4G_2022_SW9_Chem MARCH4G_2022_SW9_GHG MARCH4G_2023 MARCH4G_2023_CW4b_Chem MARCH4G_2023_CW4b_GHG MARCH4G_2023_SW6b_14C MARCH4G_2023_SW6b_Chem MARCH4G_2023_SW6b_GHG MARCH4G_2023_SW7_14C MARCH4G_2023_SW7_Chem MARCH4G_2023_SW7_GHG-a Methane Microportable Greenhouse Gas Analyzer Portable 2-channel multimeter, Hach, HQ40D Radiocarbon AMS dating Silonite canister stable carbon isotopes Portable multimeter, Hach, HQ4300 Off-axis integrated cavity output spectroscopy (OA-ICOS) gas analyzer Age, 14C AMS Age, 14C calibrated, OxCal 4.4 and IntCal20 Age, 14C calibrated, IntCal20 (Reimer et al. 2020) GasBench+PreCon trace gas concentration system (ThermoFinnigan) coupled to a DELTA V plus IRMS 2021-08-05 2023-07-15 Complete 61.14541 77.719667 -69.019667 -45.11658 access rights needed CC-BY-4.0: Creative Commons Attribution 4.0 International (License comes into effect after moratorium ends) English PANGAEA Data Publisher for Earth & Environmental Science https://www.pangaea.de/ Data Center Contact Michael Diepenbroek info@pangaea.de

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Bremen Bremen 28359 Germany online 370 data points text/tab-separated-values Garnett, Mark H; Gulliver, Pauline; Billett, Michael F (2016): A rapid method to collect methane from peatland streams for radiocarbon analysis. Ecohydrology, 9(1), 113-121, https://doi.org/10.1002/eco.1617 Hatton, Jade Elizabeth; et al. (accepted): Extensive Holocene retreat of the Greenland ice sheet revealed by subglacial methane release. Nature Geoscience Yarnes, Chris (2013): δ 13 C and δ 2 H measurement of methane from ecological and geological sources by gas chromatography/combustion/pyrolysis isotope‐ratio mass spectrometry. Rapid Communications in Mass Spectrometry, 27(9), 1036-1044, https://doi.org/10.1002/rcm.6549

A field sampling campaign spanning the entire western margin of the Greenland Ice Sheet was conducted in the summer melt seasons of 2021, 2022, and 2023, to measure release of dissolved methane from meltwater streams draining the subglacial environment of the Greenland Ice Sheet. The campaign was designed to assess whether subglacial methane export is ubitiqous from the GrIS, and the source and age of this methane released. Twenty-six rivers draining from the GrIS were sampled in the summers of 2021, 2022 and 2023 along the west coast of Greenland, forming a north to south transect from Qaanaaq to Narsarsuaq. We split these rivers into regional areas of northwest (NW), central west (CW), and southwest (SW). Most of these rivers drained directly from the subglacial environment, whether via an upwelling (proglacial spring) or subglacial portal. Samples were taken as close to the upwelling or portal as possible, to get the most representative view of the subglacial system, with limited off-gassing or dilution effects from supraglacial meltwaters. Basic stream geochemistry (pH, EC, O2) was measured in the field using a WTW 3430 multimeter. Dissolved CH4 was extracted (Garnett et al., 2016) into a nitrogen headspace, via 5L water samples were collected into a 10L accordion water carrier, 1-2L of pure N2 headspace was added and the water carrier was shaken for 3 minutes to equilibrate the CH4. The headspace CH4 concentrations were measured directly in the field using a using a micro portable greenhouse gas analyser (MGGA, ABB GLA1313 Series, using Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) technology). The headspace with extracted sample was stored in a pre-evacuated 15L Silonite™ cannisters with TrueSeal Valve™ (Entech Instruments) or pre-evacuated 150ml glass serum vials (Wheaton™) using a 150 ml glass syringe and sealed with 15 mm crimped (13mm) chlorobutyl rubber stoppers (Bellco Glass) ahead of radio- and stable- carbon isotope analysis, respectively. We provide measured and 'corrected' radiocarbon ages of dissolved methane. We recognise that the CH4 extracted and measured in each water sample is a homogenised sample, likely containing subglacially produced CH4 combined with some modern CH4, when supraglacial water is routed through moulins to the bed and through the subglacial system. Therefore, it is likely that our water samples encompass some portion of modern-day CH4, and accounting for this provides a more accurate assessment of the 14C-age of the subglacial carbon source for methanogenesis. We used a simple mass balance approach to consider what proportion of our sampled CH4 is potentially modern-day atmospheric, based on the measured atmospheric CH4 concentration measured during a survey of the supraglacial area inland. ** For all details see the full metadata description at "https://doi.pangaea.de/10.1594/PANGAEA.993007"!

http://en.wikipedia.org/wiki/ISO_6709 LATITUDE http://en.wikipedia.org/wiki/ISO_6709 LONGITUDE http://en.wikipedia.org/wiki/ISO_8601 DATE/TIME https://c14.arch.ox.ac.uk/oxcal.html Age, 14C calibrated, OxCal 4.4 and IntCal20 https://doi.org/10.1002/eco.1617 A rapid method to collect methane from peatland streams for radiocarbon analysis https://doi.org/10.1002/rcm.6549 δ 13 C and δ 2 H measurement of methane from ecological and geological sources by gas chromatography/combustion/pyrolysis isotope‐ratio mass spectrometry https://doi.org/10.1017/RDC.2020.41 Age, 14C calibrated, IntCal20 (Reimer et al. 2020) https://doi.org/10.1146/annurev.ns.30.120180.002253 Age, 14C AMS https://en.wikipedia.org/wiki/Deuterium δ Deuterium, methane https://en.wikipedia.org/wiki/Electrical_conductivity Conductivity https://en.wikipedia.org/wiki/ISO_8601 Date/Time local https://sensor.awi.de/?id=7276 Microportable Greenhouse Gas Analyzer DIF 9.4 2026-03-30 2026-03-30