Tony Heald / Glaucous Gull (Larus hyperboreus) taking off from ice, Svalbard Norway, July.

Jordi Chias / Leopard seal (Hydrurga leptonyx) resting over an iceberg, Antarctic Peninsula, Antarctica.

Jordi Chias / Gentoo penguins (Pygoscelis papua) swimming together and porpoising in search of krill, Antarctic Peninsula, Antarctica.

Danny Green / Sea otter (Enhydra lutris) resting on sea ice, Alaska, USA, June

Danny Green / Sea otter (Enhydra lutris) resting amongst sea ice, Alaska, USA, June

Danny Green / Sea otters (Enhydra lutris) resting on ice, Alaska, USA, June

David Tipling / Snow petrel (Pagadroma nivea nivea) flying around Iceberg off South Georgia, Southern Ocean January

Frederique Olivier / Adelie penguins (Pygoscelis adeliae) swimming underneath sea ice, Antarctica.

Frederique Olivier / Wide-angle shot of a group of Emperor penguin (Aptenodytes forsteri) chicks walking on sea ice, Adelie Land, Antarctica, January.

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) chick begging for food from parent, Adelie Land, Antarctica, January.

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) walking with chick, Adelie Land, Antarctica, January.

Frederique Olivier / Close-up of a group of Emperor penguin (Aptenodytes forsteri) chicks huddled together in a blizzard, covered in snow, Adelie Land, Antarctica, January.