Algae drive enhanced darkening of bare ice on the Greenland ice sheet

Authors Organisations
  • Marek Stibal(Author)
    University of Copenhagen
  • Jason Box(Author)
    Geological Survey of Denmark and Greenland
  • Karen Cameron(Author)
  • Peter L. Langen(Author)
    Danish Meteorological Institute
  • Marian L. Yallop(Author)
    University of Bristol
  • Ruth H. Mottram(Author)
    Danish Meteorological Institute
  • Alia L. Khan(Author)
    University of Colorado Boulder
  • Noah P. Molotch(Author)
    University of Colorado Boulder
    California Institute of Technology
  • Nathan A. M. Chrismas(Author)
    University of Bristol
  • Filippo Calì Quaglia(Author)
    Geological Survey of Denmark and Greenland
    University of Turin
  • Daniel Remias(Author)
    University of Applied Sciences Upper Austria
  • C. J. Paul Smeets(Author)
    Utrecht University
  • Michiel R. van den Broeke(Author)
    Utrecht University
  • Jonathan Ryan(Author)
  • Alun Hubbard(Author)
  • Martyn Tranter(Author)
    University of Bristol
  • Dirk Van As(Author)
    Geological Survey of Denmark and Greenland
  • Andreas P. Ahlstrøm(Author)
    Geological Survey of Denmark and Greenland
Type Article
Original languageEnglish
Pages (from-to)11463-11471
Number of pages9
JournalGeophysical Research Letters
Volume44
Issue number22
Early online date18 Nov 2017
DOI
Publication statusPublished - 28 Nov 2017
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Abstract

Surface ablation of the Greenland ice sheet is amplified by surface darkening caused by light-absorbing impurities such as mineral dust, black carbon, and pigmented microbial cells. We present the first quantitative assessment of the microbial contribution to the ice sheet surface darkening, based on field measurements of surface reflectance and concentrations of light-absorbing impurities, including pigmented algae, during the 2014 melt season in the southwestern part of the ice sheet. The impact of algae on bare ice darkening in the study area was greater than that of non-algal impurities and yielded a net albedo reduction of 0.038 ± 0.0035 for each algal population doubling. We argue that algal growth is a crucial control of bare ice darkening, and incorporating the algal darkening effect will improve mass balance and sea level projections of the Greenland ice sheet and ice masses elsewhere

Keywords

  • greenland ice sheet, algae, albedo, light-absorbing impurities, melting

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