Dark ice in a warming world: advances and challenges in the study of Greenland Ice Sheet's biological darkening

• Published in: Annals of Glaciology
• Main Authors: Laura Halbach, Lou-Anne Chevrollier, Joseph M. Cook, Ian T. Stevens, Martin Hansen, Alexandre M. Anesio, Liane G. Benning, Martyn Tranter
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2022
• Subjects: Albedo; BioSNICAR; glacier ice algae; growth; hydrology; model; mortality; weathering crust; Meteorology. Climatology; QC851-999; Greenland; Annals of Glaciology; glacier; ice algae; Ice Sheet
• Online Access: https://doi.org/10.1017/aog.2023.17; https://doaj.org/article/8925792b411440b3b12ccc773b93fec8

The surface of the Greenland Ice Sheet is darkening, which accelerates its surface melt. The role of glacier ice algae in reducing surface albedo is widely recognised but not well quantified and the feedbacks between the algae and the weathering crust remain poorly understood. In this letter, we summarise recent advances in the study of the biological darkening of the Greenland Ice Sheet and highlight three key research priorities that are required to better understand and forecast algal-driven melt: (i) identifying the controls on glacier ice algal growth and mortality, (ii) quantifying the spatio-temporal variability in glacier ice algal biomass and processes involved in cell redistribution and (iii) determining the albedo feedbacks between algal biomass and weathering crust characteristics. Addressing these key research priorities will allow us to better understand the supraglacial ice-algal system and to develop an integrated model incorporating the algal and physical controls on ice surface albedo.