[en] Climate-driven retreat of Greenland’s marine-terminating glaciers in rapidly transforming fjord systems has potential implications for marine methane cycling. Because the Greenland ice sheet and its basal meltwaters have been identified as sources of methane, it has been hypothesized that fjords fed by marine-terminating glaciers should be associated with elevated dissolved methane concentrations and enhanced sea-air exchange. Here, we test this hypothesis by comparing two adjacent fjords in southwest Greenland (Narsaq region), one currently fed by a marine-terminating glacier, and one supplied by a pro-glacial river draining a glacier that has retreated inland. Measurements collected during the summers of 2023 and 2024 reveal remarkably similar dissolved methane concentrations, vertical distributions and saturation levels in both fjords. Methane concentrations were highest in surface meltwaters and fjord waters and lower in intruding oceanic waters into the fjords, with no evidence for significant methane inputs from the seafloor. Overall, the observed methane concentrations (4.94 – 9.30 nM) correspond to a surface layer (0-3m) saturation of 129-226% resulting in small atmospheric fluxes from 0.49 to 3.31 µmol m
-2
d
-1
. High-resolution measurements using a membrane inlet laser spectrometer (MILS) further revealed no detectable fine-scale methane enrichment near the glacier front. We attribute the similarity in dissolved methane distributions between the two fjords to the dominance of surface meltwater discharge during summer, even in the presence of a marine-terminating glacier, suggesting that southern Greenland fjords represent a relatively weak source of atmospheric methane under summer conditions. Our results suggest that ongoing retreat from marine-terminating to land-terminating glaciers is unlikely to substantially enhance methane emission from Greenland fjords under present and near-future summer conditions. Wintertime measurements remain needed to fully constrain annual methane budgets in these fjords.
Research Center/Unit :
FOCUS - Freshwater and OCeanic science Unit of reSearch - ULiège
Disciplines :
Earth sciences & physical geography
Author, co-author :
Hassler, Christel; Ecole Polytechnique Fédérale de Lausanne, ENAC, Smart Environmental Sensing in Extreme Environments (SENSE)
Delille, Bruno ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO)
Lavanchy, Sébastien; Ecole Polytechnique Fédérale de Lausanne, ENAC, Smart Environmental Sensing in Extreme Environments (SENSE)
Cruz, Hugo; Ecole Polytechnique Fédérale de Lausanne, ENAC, Smart Environmental Sensing in Extreme Environments (SENSE)
Grilli, Roberto; University Grenoble Alpes, CNRS, IRD, Grenoble INP, Institut des Géosciences de l'Environnement (IGE)
Jaccard, Samuel; Institute of Earth Sciences, University of Lausanne
Chappellaz, Jérôme; Ecole Polytechnique Fédérale de Lausanne, ENAC, Smart Environmental Sensing in Extreme Environments (SENSE)
Language :
English
Title :
Low methane supersaturation observed in southwestern Greenland fjords
Borges A., Champenois W., Gypens N., Delille B., Harlay J., (2016). Massive marine methane emissions from near-shore shallow coastal areas. Sci. Rep. 6, 27908. doi: 10.1038/srep27908, 27283125.
Christiansen J. R., Jørgensen C. J., (2018). First observation of direct methane emission to the atmosphere from the subglacial domain of the Greenland ice sheet. Sci. Rep. 8, 16623. doi: 10.1038/s41598-018-35054-7, 30413774.
Colson B. C., Michel A. P. M., (2025). Membrane equilibration for in situ dissolved gas instrumentation: a comparison of four approaches. Front. Membr. Sci. Technol. 4, 1488800. doi: 10.3389/frmst.2025.1488800.
Damm E., Erickson Y., Falck E.. (2021). Waterside convection and stratification control methane spreading in supersaturated Arctic fjords (Spitsbergen). Cont Shelf Res 224, 104473. doi: 10.1016/j.csr.2021.104473.
Damm E., Rudels B., Schauer U., Mau S., Dieckmann G. (2015). Methane excess in Arctic surface water – triggered by sea ice formation and melting. Scientific Reports 5, 16179. doi: 10.1038/srep16179.
Damm E., Schauer U., Rudels B., Hass C.. (2007). Excess of bottom-released methane in an Arctic shelf sea polynya in winter. Cont Shelf Res 27, 1692–1701. doi: 10.1016/j.csr.2007.02.003.
Damm E., Mackensen A., Budéus G., Faber E., Hanfland C.. (2005). Pathways of methane in seawater: plume spreading in an Arctic shelf environment (SW-Spitsbergen). Cont Shelf Res 25, 1453–1472. doi: 10.1016/j.csr.2005.03.003.
Dieser M., Broemsen E. L. J. E., Cameron K. A., King G. M., Achberger A., Choquette K., et al. (2014). Molecular and biogeochemical evidence for methane cycling beneath the western margin of the Greenland ice sheet. ISME J. 8, 2305–2316. doi: 10.1038/ismej.2014.59, 24739624.
Dolven K. O., Vierinen J., Grilli R., Triest J., Ferré B., (2022). Response time correction of slow-response sensor data by deconvolution of the growth-law equation. Geosci. Instrum. Method. Data Syst. 11, 293–306.
Ernst L., Steinfeld B., Barayeu U., Klintzsch T., Kurth M., Grimm D., et al. (2022). Methane formation driven by reactive oxygen species across all living organisms. Nature 603, 482–487. doi: 10.1038/s41586-022-04511-9, 35264795.
Fofonoff N. P., Millard R. C. Jr.. (1983). Algorithms for computation of fundamental properties of seawater. UNESCO technical papers in marine science, No. 44. (Paris, France: UNESCO), 53. doi: 10.25607/OBP-1450.
Gardner A., Fahnestock M., Scambos T.. (2022). MEaSUREs ITS_LIVE landsat image-pair glacier and ice sheet surface velocities, version 1. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: 10.5067/IMR9D3PEI28U.
Gräff D., Lipovsky B. P., Vieli A., Dachauer A., Jackson R. H., Farinotti D., et al. (2025). Calving-driven fjord dynamics resolved by seafloor fibre sensing. Nature 644, 404–412. doi: 10.1038/s41586-025-09347-7.
Grilli R., Birot D., Schumacher M., Paris J.-D., Blouzon C., Donval J. P., et al. (2021). Inter-comparison of the spatial distribution of methane in the water column from seafloor emissions at two sites in the western Black Sea using a multi-technique approach. Front. Earth Sci. 9, 626372. doi: 10.3389/feart.2021.626372.
Grilli R., DelSontro T., Garnier J., Jacob F., Némery J., (2023). A novel high-resolution in situ tool for studying carbon biogeochemical processes in aquatic systems: the Lake Aiguebelette case study. J. Geophys. Res. Biogeosci. 128, e2022JG007200. doi: 10.1029/2022JG007200, 29143083.
Grilli R., Triest J., Chappellaz J., Calzas M., Desbois T., Jansson P., et al. (2018). Sub-Ocean: Subsea dissolved methane measurements using an embedded laser spectrometer technology. Environ. Sci. Technol. 52, 10543–10551. doi: 10.1021/acs.est.7b06171, 30111096.
Hansen K., Karlsson N. B., How P., Poulsen E., Mortensen J., Rysgaard S., (2025). Winter subglacial meltwater detected in a Greenland fjord. Nat. Geosci. 18, 219–225. doi: 10.31223/x5bx16, 35033490.
IPCC. (2021). Climate change 2021: the physical science basis. In: Masson-Delmotte V., Zhai P., Pirani A., Connors S. L., Péan C., Berger S., et al. (eds.) Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. (Cambridge, UK: Cambridge University Press).
Mau S., Blees J., Helmke E., Niemann H., Damm E.. (2013). Vertical distribution of methane oxidation and methanotrophic response to elevated methane concentrations in stratified waters of the Arctic fjord Storfjorden (Svalbard, Norway). Biogeosciences 10, 6267–6278. doi: 10.5194/bg-10-6267-2013.
Jähne B., Heinz G., Dietrich W., (1987). Measurement of the diffusion coefficients of sparingly soluble gases in water. J. Geophys. Res. Oceans. 92, 10767–10776.
Jansson P., Triest J., Grilli R., Ferré B., Silyakova A., Mienert J., et al. (2019). High-resolution underwater laser spectrometer sensing provides new insights into methane distribution at Arctic seepages site. Ocean Sci. 15, 1055–1069. doi: 10.5194/os-15-1055-2019.
Jørgensen C. J., Mønster J., Fuglsang K., Christiansen J. R., (2020). Continuous methane concentration measurements at the Greenland ice sheet–atmosphere interface using a low-cost, low-power metal oxide sensor system. Atmos. Meas. Tech. 13, 3319–3328. doi: 10.5194/amt-13-3319-2020.
Kapit J. A., Youngs S., Pardis W. A., Padilla A. M., Michel A. P. M., (2024). An underwater methane sensor based on laser spectroscopy in a hollow core optical fiber. ACS Sens. 9, 5896–5905. doi: 10.1021/acssensors.4c01563, 39523583.
Kitidis V., Upstill-Goddard R. C., Anderson L. G.. (2010). Methane and nitrous oxide in surface water along the North-West Passage, Arctic Ocean. Mar Chem 121, 80–86. doi: 10.1016/j.marchem.2010.03.006.
Kleber G. E., Hodson A. J., Magerl L., Mannerfelt E. S., Bradbury H. J., Zhu Y., et al. (2023). Groundwater springs formed during glacial retreat are a large source of methane in the high Arctic. Nat. Geosci. 16, 597–604. doi: 10.1038/s41561-023-01210-6, 37880705.
Kleber G. E., Magerl L., Turchyn A. V., Schloemer S., Trimmer M., Zhu Y., et al. (2025). Proglacial methane emissions driven by meltwater and groundwater flushing in a high-Arctic glacial catchment. Biogeosciences 22, 659–674. doi: 10.5194/bg-22-659-2025.
Klintzsch T., Geisinger H., Wieland A., Langer G., Nehrke G., Bizic M., et al. (2023). Stable carbon isotope signature of methane released from phytoplankton. Geophys. Res. Lett. 50, e2023GL103317. doi: 10.1029/2023GL103317, 29143083.
Kudo K., Yamada K., Toyoda S., Yoshida N., Sasano D., Kosugi N., et al. (2018). Spatial distribution of dissolved methane and its source in the western Arctic Ocean. J Oceanogr 74, 305–317. doi: 10.1007/s10872-017-0460-y.
Lamarche-Gagnon G., Wadham J. L., Sherwood Lollar B., Arndt S., Fietzek P., Beaton A. D., et al. (2019). Greenland melt drives continuous export of methane from the ice-sheet bed. Nature 565, 73–77. doi: 10.1038/s41586-018-0800-0, 30602750.
Lorenson T. D., Greinert J., Coffin R. B., Rehder G.. (2016). Dissolved methane in the Beaufort Sea and the Arctic Ocean, 1992–2009: sources and atmospheric flux. Limnol Oceanogr 61, S300–S323. doi: 10.1002/lno.10457.
Mankoff K. D., Brice N., Fettweis X., Ahlstrøm A. P., Colgan W., Kondo K., et al. (2020). Greenland liquid water discharge from 1958 through 2019. Earth Syst. Sci. Data 12, 2811–2841. doi: 10.5194/essd-12-2811-2020.
Mankoff K. D., Tulaczyk S. M.. (2017). The past, present, and future viscous heat dissipation available for Greenland subglacial conduit formation. Cryosphere 11, 303–317. doi: 10.5194/tc-11-303-2017.
Manning C. C. M., Nicholson D. P., (2022). dnicholson/gas_toolbox: MATLAB code for calculating gas fluxes. Zenodo. doi: 10.5281/zenodo.6126685.
Mao S.-H., Zhang H.-H., Zhuang G.-C., Li X.-J., Liu Q., Zhou Z., et al. (2024). Marine methane paradox: enigmatic production of methane in oxygenated waters. Innovation Geosci. 2, 100071. doi: 10.59717/j.xinn-geo.2024.100071.
Mao S. H., Zhang H. H., Zhuang G. C., Li X.-J., Liu O., et al. (2022). Aerobic oxidation of methane significantly reduces global diffusive methane emissions from shallow marine waters. Nat. Commun. 13, 7309. doi: 10.1038/s41467-022-35082-y, 36437260.
Meire L., Mortensen J., Meire P., Juul-Pedersen T., Sejr M. K., Rysgaard S., et al. (2017). Marine-terminating glaciers sustain high productivity in Greenland fjords. Glob. Change Biol. 23, 5344–5357. doi: 10.1111/gcb.13801, 28776870.
Morville J., Romanini D., Kerstel E., (2014). “ Cavity enhanced absorption spectroscopy with optical feedback, ” in Cavity-Enhanced Spectroscopy and Sensing. Eds. Gagliardi G., Loock H.-P., ( Springer, Berlin Heidelberg), 163–209.
Nightingale P. D., Malin G., Law C. S., Watson A. J., Liss P. S., Liddicoat M. I., et al. (2000). In situ evaluation of air-sea gas exchange parameterizations using novel conservative and volatile tracers. Global Biogeochem Cycles 14, 373–387. doi: 10.1029/1999GB900091.
Overeem I., Hudson B. D., Syvitski J. P. M., Mikkelsen A. B., Hasholt B., van den Broeke M. R., et al. (2017). Substantial export of suspended sediment to the global oceans from glacial erosion in Greenland. Nat. Geosci. 10, 859–863. doi: 10.1038/ngeo3046, 37880705.
Perez-Coronel E., Beman M. J., (2022). Multiple sources of aerobic methane production in aquatic ecosystems include bacterial photosynthesis. Nat. Commun. 13, 6454. doi: 10.1038/s41467-022-34105-y, 36309500.
Ploug H., Kühl M., Buchholz-Cleven B., Jørgensen B. B.. (1997). Anoxic aggregates – an ephemeral phenomenon in the pelagic environment? Aquat Microb Ecol 13, 285–294. doi: 10.3354/ame013285.
Poinart K., Box J. E., Mote T. L., Loomis B. D., Smith B. E., Medley B. C., et al. (2024). Greenland ice sheet. In: NOAA Arctic report card 2024. doi: 10.25923/njxd-b82.
Portnov A., Vadakkepuliyambatta S., Mienert J., Hubbard A., (2016). Ice-sheet-driven methane storage and release in the Arctic. Nat. Commun. 7, 10314. doi: 10.1038/ncomms10314, 26739497.
Repeta D., Ferrón S., Sosa O., Johnson C. G., Repeta L. D., Acker M., et al. (2016). Marine methane paradox explained by bacterial degradation of dissolved organic matter. Nat. Geosci. 9, 884–887. doi: 10.1038/ngeo2837, 37880705.
Rhee T. S., Kettle A. J., Andreae M. O., (2009). Methane and nitrous oxide emissions from the ocean: a reassessment using basin-wide observations in the Atlantic. J. Geophys. Res. 114, D12304. doi: 10.1029/2008JD011662, 29143083.
Rocher-Ros G., Stanley E. H., Loken L. C., Casson L. C., Raymond P. A., Liu S., et al. (2023). Global methane emissions from rivers and streams. Nature 621, 530–535. doi: 10.1038/s41586-023-06344-6, 37587344.
Rodes N., Betlem P., Senger K., Römer M., Hodson A., Liira M., et al. (2023). Active gas seepage in western Spitsbergen fjords, Svalbard archipelago: spatial extent and geological controls. Front. Earth Sci. 11, 1173477. doi: 10.3389/feart.2023.1173477.
Rosentreter J. A., Borges A. V., Deemer B. R., Holgerson M. A., Liu S., Song C., et al. (2021). Half of global methane emissions come from highly variable aquatic ecosystem sources. Nat. Geosci. 14, 225–230. doi: 10.1038/s41561-021-00715-2, 37880705.
Straneo F., Cenedese C., (2015). The dynamics of Greenland’s glacial fjords and their role in climate. Annu. Rev. Mar. Sci. 7, 89–112. doi: 10.1146/annurev-marine-010213-135133, 25149564.
Strock K. E., Krewson R., Hayes N. M., Deemer B. R.. (2024). Oxidation is a potentially significant methane sink in land-terminating glacial runoff. Sci Rep 14, 23389. doi: 10.1038/s41598-024-73041-3.
Szymczycha B., Diak M., Hong W.-L., Böttcher M. E., Lepland A., Makuch P., et al. (2025). Submarine groundwater discharge and gas hydrate dissociation fuel organic matter formation in Arctic fjord sediments. Mar. Chem. 273, 104570. doi: 10.1016/j.marchem.2025.104570, 38826717.
Triest J., Chappellaz J., Grilli R., (2017). “ System forfast and in-situ sampling of dissolved gases in the ocean, ” in Patent 08276-01 ( CNRS, Grenoble, France).
Upstill-Goddard R. C., Rees A. P., Owens N. J. P., (1996). Simultaneous high-precision measurements of methane and nitrous oxide in water and seawater by single phase equilibration gas chromatography. Deep Sea Res. I. 43, 1669–1682. doi: 10.1016/s0967-0637(96)00074-x.
Verdugo J., Damm E., Schaffer J., Bauch D., Meyer H., Kaiser J.. (2022). Impacts of glacier and sea ice melt on methane pathways on the Northeast Greenland shelf. Cont Shelf Res 243, 104752. doi: 10.1016/j.csr.2022.104752.
Vinogradova E., Damm E., Pnyushkov A. V., Krumpen T., Ivanov V. V.. (2022). Shelf-sourced methane in surface seawater at the Eurasian continental slope (Arctic Ocean). Front Environ Sci 10, 811375. doi: 10.3389/fenvs.2022.811375.
Vogt J., Risk D., Bourlon E., Azetsu-Scott K., Edinger E. N., Sherwood O. A., et al. (2023). Sea-air methane flux estimates derived from marine surface observations and instantaneous atmospheric measurements in the northern Labrador Sea and Baffin Bay. Biogeosciences 20, 1773–1787. doi: 10.5194/bg-20-1773-2023.
Wanninkhof R., (2014). Relationship between wind speed and gas exchange over the ocean revisited. Limnol. Oceanogr. Methods 12, 351–362. doi: 10.4319/lom.2014.12.351.
Weiss R. F., (1981). Determinations of carbon dioxide and methane by dual catalyst flame ionization chromatography and nitrous oxide by electron capture chromatography. J. Chromatographic Sci. 19, 611–616. doi: 10.1093/chromsci/19.12.611, 40388063.
Wiesenberg D. A., Guinasso N. L., (1979). Equilibrium solubilities of methane, carbon monoxide, and hydrogen in water and sea water. J. Chem. Eng. Data 24, 356–360.
Wood M., Carroll D., Fenty I., Bertin C., Darby B., Dutkiewicz S., et al. (2025). Increased melt from Greenland’s most active glacier fuels enhanced coastal productivity. Commun. Earth Environ. 6, 626. doi: 10.1038/s43247-025-02599-1, 37880705.
Ye J., Zhuang M., Hong M., Zhang D., Ren G., Hu A., et al. (2024). Methanogenesis in the presence of oxygenic photosynthetic bacteria may contribute to global methane cycle. Nat. Commun. 15, 5682. doi: 10.1038/s41467-024-50108-3, 38971854.
Ye W., Li Y., Wen J., Zhang J., Shakhova N., Liu J., et al. (2023). Enhanced transport of dissolved methane from the Chukchi Sea to the central Arctic. Global Biogeochem Cycles 37, e2022GB007368. doi: 10.1029/2022GB007368.
