Light absorption and albedo reduction by pigmented microalgae on snow and ice ...

• Main Authors: Chevrollier, Lou-Anne, Cook, Joseph M., Halbach, Laura, Jakobsen, Hans, Benning, Liane G., Anesio, Alexandre M., Tranter, Martyn
• Format: Text
• Language: unknown
• Published: Freie Universität Berlin 2023
• Subjects: Glacier modelling; glaciological model experiments; ice biology; melt-surface; snow/ice surface processes; 500 Naturwissenschaften und Mathematik550 Geowissenschaften, Geologie550 Geowissenschaften; Greenland; glacier; ice algae; Ice Sheet
• Online Access: https://dx.doi.org/10.17169/refubium-36072; https://refubium.fu-berlin.de/handle/fub188/36356

Pigmented microalgae inhabiting snow and ice environments lower the albedo of glacier and ice-sheet surfaces, significantly enhancing surface melt. Our ability to accurately predict their role in glacier and ice-sheet surface mass balance is limited by the current lack of empirical data to constrain their representation in predictive models. Here we present new empirical optical properties for snow and ice algae and incorporate them in a radiative transfer model to investigate their impact on snow and ice surface albedo. We found ice algal cells to be more efficient absorbers than snow algal cells, but their blooms had comparable impact on surface albedo due to the different photic conditions of their habitats. We then used the model to reconstruct the effect of ice algae on bare ice albedo spectra collected at our field site in southern Greenland, where blooms dropped the albedo locally by between 3 and 43%, equivalent to 1-10 L m(-2) d(-1) of melted ice. Using the newly parametrized model, future studies ...