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dc.contributor.authorCook, Joseph M.
dc.contributor.authorTedstone, Andrew J.
dc.contributor.authorWilliamson, Christopher
dc.contributor.authorMcCutcheon, Jenine
dc.contributor.authorHodson, Andrew J.
dc.contributor.authorDayal, Archana
dc.contributor.authorSkiles, McKenzie
dc.contributor.authorHofer, Stefan
dc.contributor.authorBryant, Robert
dc.contributor.authorMcAree, Owen
dc.contributor.authorMcGonigle, Andrew
dc.contributor.authorRyan, Jonathan
dc.contributor.authorAnesio, Alexandre M.
dc.contributor.authorIrvine-Fynn, Tristram D.L.
dc.contributor.authorHubbard, Alun Lloyd
dc.contributor.authorHanna, Edward
dc.contributor.authorFlanner, Mark
dc.contributor.authorMayanna, Sathish
dc.contributor.authorBenning, Liane G.
dc.contributor.authorvan As, Dirk
dc.contributor.authorYallop, Marian
dc.contributor.authorMcQuaid, James B.
dc.contributor.authorGribbin, Thomas
dc.contributor.authorTranter, Martyn
dc.date.accessioned2020-02-04T11:45:23Z
dc.date.available2020-02-04T11:45:23Z
dc.date.issued2020-01-29
dc.description.abstractMelting of the Greenland Ice Sheet (GrIS) is the largest single contributor to eustatic sea level and is amplified by the growth of pigmented algae on the ice surface, which increases solar radiation absorption. This biological albedo-reducing effect and its impact upon sea level rise has not previously been quantified. Here, we combine field spectroscopy with a radiative-transfer model, supervised classification of unmanned aerial vehicle (UAV) and satellite remote-sensing data, and runoff modelling to calculate biologically driven ice surface ablation. We demonstrate that algal growth led to an additional 4.4–6.0 Gt of runoff from bare ice in the south-western sector of the GrIS in summer 2017, representing 10 %–13 % of the total. In localized patches with high biomass accumulation, algae accelerated melting by up to 26.15±3.77 % (standard error, SE). The year 2017 was a high-albedo year, so we also extended our analysis to the particularly low-albedo 2016 melt season. The runoff from the south-western bare-ice zone attributed to algae was much higher in 2016 at 8.8–12.2 Gt, although the proportion of the total runoff contributed by algae was similar at 9 %–13 %. Across a 10 000 km2 area around our field site, algae covered similar proportions of the exposed bare ice zone in both years (57.99 % in 2016 and 58.89 % in 2017), but more of the algal ice was classed as “high biomass” in 2016 (8.35 %) than 2017 (2.54 %). This interannual comparison demonstrates a positive feedback where more widespread, higher-biomass algal blooms are expected to form in high-melt years where the winter snowpack retreats further and earlier, providing a larger area for bloom development and also enhancing the provision of nutrients and liquid water liberated from melting ice. Our analysis confirms the importance of this biological albedo feedback and that its omission from predictive models leads to the systematic underestimation of Greenland's future sea level contribution, especially because both the bare-ice zones available for algal colonization and the length of the biological growth season are set to expand in the future.en_US
dc.identifier.citationCook JM, Tedstone AJ, Williamson CJ, McCutcheon, Hodson, Dayal, Skiles, Hofer S, Bryant, McAree, McGonigle, Ryan J, Anesio, Irvine-Fynn TD, Hubbard AL, Hanna E, Flanner MG, Mayanna, Benning, van As D, Yallop M, McQuaid JB, Gribbin, Tranter M. Glacier algae accelerate melt rates on the south-western Greenland Ice Sheet. The Cryosphere. 2019;14:309-338en_US
dc.identifier.cristinIDFRIDAID 1790410
dc.identifier.doi10.5194/tc-14-309-2020
dc.identifier.issn1994-0416
dc.identifier.issn1994-0424
dc.identifier.urihttps://hdl.handle.net/10037/17320
dc.language.isoengen_US
dc.publisherEuropean Geosciences Union (EGU)en_US
dc.relation.journalThe Cryosphere
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2020 The Author(s)en_US
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450en_US
dc.titleGlacier algae accelerate melt rates on the south-western Greenland Ice Sheeten_US
dc.type.versionpublishedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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