Theo Bosboom / Autumn foliage including Beech and Oak leaves and Rowan berries floating in the current of a mountain stream, La Hoegne, Ardennes, Belgium.

Theo Bosboom / Autumn leaves from Beech trees, Oak trees and Birch trees floating under water in the current of a mountain stream, La Hoegne, Ardennes, Belgium.

Theo Bosboom / Autumn leaves from Beech, Oak and Birch trees floating on water, taken from underwater, Ardennes, La Hoegne, Belgium.

Theo Bosboom / Oak and Beech tree leaves in autumn colours floating on water of mountain stream, La Hoegne / High Fenn, Ardennes, Belgium

Theo Bosboom / Yellow coloured Birch leaf (Betula) floating on the bubbles and foam of a stream, De Veluwe (Leuvenumse bos), Netherlands.

Frederique Olivier / Northern sea otter (Enhydra lutris kenyoni) sleeping at dusk, Kachemak Bay, Alaska, USA.

Frederique Olivier / Northern sea otter (Enhydra lutris kenyoni) swimming, floating on its back, Kachemak Bay, Alaska, USA.

Frederique Olivier / Northern sea otter (Enhydra lutris kenyoni) sleeping, floating on the surface, Kachemak Bay, Alaska, USA.

Alastair MacEwen / Time-lapse of toadspawn from a Common toad (Bufo bufo) developing, emerging and feeding on nutrient jelly, Somerset, England, UK, April.

John Waters / Group of Common frogs (Rana temporaria) spawning in a garden pond, with floating spawn, Somerset, England, UK, March.

Ingo Arndt / Mastigias jellyfish (Mastigias sp) with mass of jellyfish in background, Jellyfish lake, Palau, Western Pacific Islands, Micronesia

Ingo Arndt / Mass of Mastigias jellyfish (Mastigias sp) in Jellyfish lake, Palau, Western Pacific Islands, Micronesia, March 2009