Roland Seitre / Pod of Common Dolphin (Delphinus delphis) under water surface. The Azores.

Brent Stephenson / Huge iceberg with streaked sky under expansive open sky. Drake Passage, near the South Shetland Islands, Antarctica, December.

Sven Zacek / Waves washing up a beach under dark clouds. Hiiumaa Island, Estonia, Europe, August 2011.

Sven Zacek / Waves washing up a beach on the Baltic coast of Estonia under sunset lit clouds. Europe, August 2011.

Ole Jorgen Liodden / Galapagos Sea Lion (Zalophus wolllebaeki) under the surface. Galapagos

Graham Eaton / Under the ice scene of freshwater frozen lake. Llyn Dinas, Snowdonia, Wales, December 2010.

Eric Baccega / Melting ice under expansive clouds. Floe Edge, Arctic Bay, Baffin Island, Nunavut, Canada, April 2009.

Floris van Breugel / Reflections of winter trees in water, under classically grey winter skies, Oisterwijk, Netherlands, Europe. December 2006.

Alex Mustard / Lemon shark (Negaprion brevirostris) under sun rays. Little Bahama Bank, Bahamas. West Atlantic Ocean.

Eric Baccega / Icebergs and glacier under clear blue sky, Croker Bay, Devon Island, Nunavut, Canada, August 2010

Eric Baccega / Devon Island, under cloud covered sky, Nunavut, Canada. August 2010

Onne van der Wal / Crystal clear shallows under a blue sky. Exumas, Bahamas, Caribbean, June 2009.