Seasonal variability of glacier algae at the Morteratsch Glacier (Swiss Alps)

Abstract ID: 3.12380 | Accepted as Talk | Requested as: Talk | TBA | TBA

Biagio Di Mauro (1)
Roberto, Garzonio (2); Christopher, Williamson (3); Jasmin, Millar (4); Lander, Van Tricht (5, 6, 7); Giacomo, Traversa (1); Claudia, Ravasio (2); Roberto, Colombo (2)

(1) Institute of Polar Sciences National Research Council (CNR-ISP), Via Cozzi n. 53, 20125 Milano, IT
(2) University of Milano Bicocca
(3) University of Bristol
(4) Cardiff University
(5) ETH Zurich
(6) Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)
(7) Universiteit Brussel

Categories: Cryo- & Hydrosphere, Remote Sensing
Keywords: glacier, albedo, algae, mass balance, light-absorbing particles

Categories: Cryo- & Hydrosphere, Remote Sensing
Keywords: glacier, albedo, algae, mass balance, light-absorbing particles

Abstract

Glacier melting can be amplified or dampened by different processes. Among the positive feedback mechanisms identified on mountain glaciers, albedo decrease is one of the most potent. In the ablation area of mountain glaciers, surface albedo can decrease due to multiple factors such as: accumulation of impurities, presence of liquid water, crevassing etc. Albedo reduction mediated by living organisms such as algae is acknowledged to promote surface melting both in alpine and polar areas. In this contribution, we analysed drone surveys and Sentinel-2 satellite data of the ablation area of the Morteratsch Glacier (Swiss Alps) during the 2017-2024 period. This particular glacier is known to host glacier algae communities (Ancylonema nordenskioeldii and Mesotaenium berggrenii) that foster the ice-albedo feedback. We leveraged in situ field spectroscopy data and algae counts to parameterize the BioSNICAR model. These simulations have been then used to estimate the concentration and radiative forcing of glacier algae. Sentinel-2 satellite data have been used to map the inter- and intra-seasonal variability of glacier algae concentration on the Morteratsch Glacier. We found that the area with algae over the study period strongly varied annually. Comparison with mass balance measurements showed that the algae might have an important impact on the amount of ice melt. In the next steps, we will continue with the temporal and spatial analysis and directly link the presence of the algae to surface elevation change and mass balance patterns This work has been supported by the LAPSE project (Light-Absorbing ParticleS in the cryosphere and impact on water resourcEs) funded by MUR under the “PRIN22” program.