Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice Sheet
2017; American Geophysical Union; Volume: 44; Issue: 22 Linguagem: Inglês
10.1002/2017gl075958
ISSN1944-8007
AutoresMarek Stibal, Jason E. Box, Karen A. Cameron, Peter L. Langen, Marian L. Yallop, Ruth Mottram, Alia L. Khan, N. P. Molotch, Nathan Chrismas, Filippo Calì Quaglia, Daniel Remias, C. J. P. P. Smeets, M. R. van den Broeke, Jonathan C. Ryan, Alun Hubbard, Martyn Tranter, Dirk van As, Andreas P. Ahlstrøm,
Tópico(s)Geology and Paleoclimatology Research
ResumoAbstract 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 nonalgal 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.
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