Bubbles
Fig. 2: Lake Sils (Plaun da Crot), the Grisons: Big bubbles, no troubles. Could be used for a mineral water commercial — if the lake was only clearer :-) — Nikon Coolpix, UK-Germany Housing, Subtronic Gamma Strob, Plaun da Crot, Lake Sils, Grisons, 3 August 2002