Photobiological Effects on Ice Algae of a Rapid Whole-Fjord Loss of Snow Cover during Spring Growth in Kangerlussuaq, a West Greenland Fjord

Snow cover on sea ice is the most important factor controlling light availability for algae, but it predicted by climate models to become more variable and stochastic. Here, we document effects of a sudden, complete loss entire snow first-year at Kangerlussuaq Fjord, West Greenland, due natural Föhn wind event that caused ca. 17 °C air temperature increase over 36 h. We applied Imaging-PAM fluorometry examine algal distribution photobiology observed rapid decrease in biomass associated with skeletal crystal layer underside had supported visible algae. Furthermore, remaining algae were photobiologically stressed, as seen significant dark-acclimated fluorescence yield (ΦPSII_max) from 0.55 before 0.41 after. However, recovery dark suggested non-photosynthetic quenching was successfully dissipating excess energy community there little photodamage. An photosynthetic efficiency α 0.22 0.16 µmol é m−2 s−1 therefore likely be photoacclimation change composition. Centric diatoms flagellates main taxa lost event, whereas specialist Nitzschia frigida increased numbers. These observations are similar those artificial snow-clearing experiments consistent clearing being useful approach investigating complex interactions between cover, irradiance fluctuations, performance.