Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice Sheet

Marek Stibal; Jason E. Box; Karen A. Cameron; Peter L. Langen; Marian L. Yallop; Ruth H. Mottram; Alia L. Khan; Noah P. Molotch; Nathan A.M. Chrismas; Filippo Calì Quaglia; Daniel Remias; C. J.P.Paul Smeets; Michiel R. van den Broeke; Jonathan C. Ryan; Alun Hubbard; Martyn Tranter; Dirk van As; Andreas P. Ahlstrøm

doi:10.1002/2017GL075958

Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice Sheet

Marek Stibal^*
, Jason E. Box
, Karen A. Cameron
, Peter L. Langen
, Marian L. Yallop
, Ruth H. Mottram
, Alia L. Khan
, Noah P. Molotch
, Nathan A.M. Chrismas
, Filippo Calì Quaglia
, Daniel Remias
, C. J.P.Paul Smeets
, Michiel R. van den Broeke
, Jonathan C. Ryan
, Alun Hubbard
, Martyn Tranter
, Dirk van As
, Andreas P. Ahlstrøm

^*Corresponding author for this work

Research output: Contribution to journal › Article › Academic › peer-review

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 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.

Original language	English
Pages (from-to)	11,463-11,471
Journal	Geophysical Research Letters
Volume	44
Issue number	22
DOIs	https://doi.org/10.1002/2017GL075958
Publication status	Published - 28 Nov 2017

Funding

This research is part of the Dark Snow Project (http://darksnow.org). It was funded by Villum Young Investigator Programme grant VKR 023121 to M. S., the Leonardo DiCaprio Foundation, and more than 700 crowd funders, and. M. S. was additionally supported by Marie Skłodowska-Curie Individual Fellowship 657533 (EMoGrIS). We acknowledge crowd funding and media support from Peter Sinclair and field assistance from Gabriel Warren and Martyn Law. The Programme for Monitoring of the Greenland Ice Sheet (www.PROMICE. dk), Greenland Analogue Project (GAP), and the K-transect AWS program of UU/IMAU made in situ automated climate station observations available. Ellen Mosley-Thompson and Michelle Cook (Ohio State University) and Waleed Abdalati (University of Colorado) provided ASD spectrometers used in the study. We also thank Anne Nolin (Oregon State University) for tips for interpreting absorption features, Joshua Schwarz (National Oceanic and Atmospheric Administration) for black carbon analysis support, and Marie Dumont (National Centre for Meteorological Research) for spectral weighting tips. The data used in this study are available as a supporting information data set.

Keywords

albedo
algae
Greenland ice sheet
light-absorbing impurities
meltings

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10.1002/2017GL075958Licence: CC BY-NC-ND

Geophysical Research Letters - 2017 - Stibal - Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice SheetFinal published version, 1.21 MBLicence: CC BY-NC-ND

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Stibal, M., Box, J. E., Cameron, K. A., Langen, P. L., Yallop, M. L., Mottram, R. H., Khan, A. L., Molotch, N. P., Chrismas, N. A. M., Calì Quaglia, F., Remias, D., Smeets, C. J. P. P., van den Broeke, M. R., Ryan, J. C., Hubbard, A., Tranter, M., van As, D., & Ahlstrøm, A. P. (2017). Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice Sheet. Geophysical Research Letters, 44(22), 11,463-11,471. https://doi.org/10.1002/2017GL075958

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title = "Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice Sheet",

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 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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author = "Marek Stibal and Box, \{Jason E.\} and Cameron, \{Karen A.\} and Langen, \{Peter L.\} and Yallop, \{Marian L.\} and Mottram, \{Ruth H.\} and Khan, \{Alia L.\} and Molotch, \{Noah P.\} and Chrismas, \{Nathan A.M.\} and \{Cal{\`i} Quaglia\}, Filippo and Daniel Remias and Smeets, \{C. J.P.Paul\} and \{van den Broeke\}, \{Michiel R.\} and Ryan, \{Jonathan C.\} and Alun Hubbard and Martyn Tranter and \{van As\}, Dirk and Ahlstr{\o}m, \{Andreas P.\}",

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Stibal, M, Box, JE, Cameron, KA, Langen, PL, Yallop, ML, Mottram, RH, Khan, AL, Molotch, NP, Chrismas, NAM, Calì Quaglia, F, Remias, D, Smeets, CJPP , van den Broeke, MR, Ryan, JC, Hubbard, A, Tranter, M, van As, D & Ahlstrøm, AP 2017, 'Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice Sheet', Geophysical Research Letters, vol. 44, no. 22, pp. 11,463-11,471. https://doi.org/10.1002/2017GL075958

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T1 - Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice Sheet

AU - Stibal, Marek

AU - Box, Jason E.

AU - Cameron, Karen A.

AU - Langen, Peter L.

AU - Yallop, Marian L.

AU - Mottram, Ruth H.

AU - Khan, Alia L.

AU - Molotch, Noah P.

AU - Chrismas, Nathan A.M.

AU - Calì Quaglia, Filippo

AU - Remias, Daniel

AU - Smeets, C. J.P.Paul

AU - van den Broeke, Michiel R.

AU - Ryan, Jonathan C.

AU - Hubbard, Alun

AU - Tranter, Martyn

AU - van As, Dirk

AU - Ahlstrøm, Andreas P.

PY - 2017/11/28

Y1 - 2017/11/28

N2 - 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.

AB - 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.

KW - albedo

KW - algae

KW - Greenland ice sheet

KW - light-absorbing impurities

KW - meltings

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JO - Geophysical Research Letters

JF - Geophysical Research Letters

IS - 22

ER -

Algae Drive Enhanced Darkening of Bare Ice on the Greenland Ice Sheet

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