Andres M. Dominguez / Dove's-foot crane's-bill leaf (Geranium molle) and algae in ice with air bubbles, Sierra de Grazalema Natural Park, southern Spain, February.

Franco Banfi / Scuba diver under ice, surfacing to the hole, viewed from underneath, Arctic circle Dive Center, White Sea, Karelia, northern Russia March 2010. No release available.

Franco Banfi / Beluga whale (Delphinapterus leucas) swimming under ice and exhaling air, with scuba diver in background, Arctic circle Dive Center, White Sea, Karelia, northern Russia, captive

Erlend Haarberg / Air bubbles frozen in ice, Helgeland, Nordland, Norway, November

Alex Mustard / Diver blowing bubble rings, while resting on the sand, East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea, January 2011.

Sven Zacek / Frozen bubbles captured in ice on the surface of lake. South Estonia, Europe, January 2008.

Pete Oxford / Galapagos penguin (Spheniscus mendiculus) diving underwater, Bartolome Island, Galapagos, endemic

Pete Oxford / Galapagos penguin (Spheniscus mendiculus) diving underwater, Bartolome Island, Galapagos, endemic.

Alex Mustard / Silhouette of a New Zealand fur seal (Arctocephalus forsteri) diving underwater, Tasmania, Australia.

Alan Williams / Male Ruddy Duck (Oxyura jamaicensis) displaying on lake expelling air from breast feathers to form bubbles (captive bird) UK, May 2010

Guy Edwardes / Beads of water trapped on vibrant green moss Landmannalaugar, Southern Iceland, July 2009.

Bryan and Cherry Alexander / Grounded iceberg, with grooves caused by air bubbles eroding ice. Greenland, 1985.