Fig. 2

February 13 daily cycle of PAR (a), temperature (b) and spectral light penetration (c) in the snow column at King George Island, Maritime Antarctica. The dotted line (a) indicates saturating irradiance level for photosynthesis in Chlorella sp. (Ek = 276 μmol photons m–2 s–1). The maximum (4,3 °C) and minimum (-1,4 °C) air temperature is presented (b)