Edwin Giesbers / Fire salamander (Salamandra salamandra) in forest habitat, Hallerbos, Belgium. May.

Philippe Clement / Female Common kingfisher (Alcedo atthis) diving and catching a Nine-spined stickleback (Pungitius pungitius) fish, stuns and eats it, Belgium, June.

Simon Littlejohn / Two European otters (Lutra lutra) hunting in the River Stour, Dorset, England, UK, May.

Simon Littlejohn / Mute swans (Cygnus olor) hissing and lunging at a European otter (Lutra lutra), River Stour, Dorset, England, UK, June.

Simon Littlejohn / Family of European otters (Lutra lutra) feeding and playing amongst Whitewater crowfoot (Ranunculus aquatilis) flowers, River Stour, Dorset, England, UK, June.

Simon Littlejohn / Close-up of a female European otter (Lutra lutra) and two juveniles feeding in a river, River Stour, Dorset, England, UK, June.

Simon Littlejohn / Female European otter (Lutra lutra) and two large pups playing and feeding in mid river, River Stour, Dorset, England, UK, June.

Danny Green / Kermode bear (Ursus americanus kermodei) standing on roots at water's edge, hunting for fish. British Columbia, Canada, September.

Danny Green / Kermode bear (Ursus americanus kermodei) hunting for Salmon in stream. British Columbia, Canada, September.

Danny Green / Bald eagle (Haliaeetus leucocephalus), two perched on rocks in front of frozen waterfall. Alaska, USA, February.

Brandon Cole / Amazon river dolphin (Inia geoffrensis) split level view showing playful dolphin with mouth open. Rio Negro, Brazil.

Brandon Cole / Piraputanga (Brycon hilarii) fish swimming in clear river with trees visible overhead. Brazil, South America.

Nick Hawkins / American white water-lily (Nymphaea odorata) growing, St. Mary's river, Nova Scotia, Canada. July.

Nick Hawkins / View of the Rio Celeste waterfall, tropical rainforest of Tenorio Volcano National Park, Costa Rica. The blue color arises due to a physical phenomenon known as Mie scattering triggered by the presenc...

Nick Hawkins / View of the Rio Celeste waterfall, tropical rainforest of Tenorio Volcano National Park, Costa Rica. The blue color arises due to a physical phenomenon known as Mie scattering triggered by the presenc...

David Hall / Split level of a Sockeye salmon (Oncorhynchus nerka) in shallow water; Adams River, British Columbia, Canada. October.

David Hall / Split level of Sockeye salmon (Oncorhynchus nerka) during migration; Adams River, British Columbia, Canada. October.

David Hall / Sockeye salmon (Oncorhynchus nerka) migration, Adams River, British Columbia, Canada. October.

David Hall / Sockeye salmon (Oncorhynchus nerka) migration, Adams River, British Columbia, Canada. October.

Derek Galon / Aerial tracking shot showing aftermath of landslides, two months after hurricane Maria, Dominica, Lesser Antilles, 2018.

Guy Edwardes / Autumn colour around the Falls of Clyde, Lanarkshire, Scotland, UK, October 2006.

Guy Edwardes / Pancake ice on the Kitka River, Kuusamo, Finland, January 2016

Klein & Hubert / African elephant (Loxodonta africana) herd crossing the Luangwa river, Luangwa National Park, Zambia

Sylvain Cordier / Golden snub-nosed monkey (Rhinopithecus roxellana),standing up on river boulders, Qinling Mountains, Shaanxi province, China

Dave Bevan / Eurasian beaver (Castor fiber) scratching before jumping into the water, alarmed, Ceredigion, Wales, UK, July.

Guy Edwardes / Landscape of Thakgil canyon, with waterfall and jagged mountains, Iceland, September.

Guy Edwardes / Long exposure of stream in Glencoe, Highland Region, Scotland, February.

Guy Edwardes / Long exposure of stream in Glencoe, Highland Region, Scotland, February.

Guy Edwardes / Mhangarstaidh Beach, Isle of Lewis, Outer Hebrides, Scotland, UK, March.

Espen Bergersen / Northern fulmar (Fulmarus glacialis) in front of the Seljalandsfoss waterfall, Iceland. May

Espen Bergersen / Aerial view of river in Landmannalaugar. Iceland. October 2017

Andres M. Dominguez / Dead Lang's short-tailed blue butterfly (Leptotes pirithous) in a river with bacterial film, Los Alcornocales Natural Park, Southern Spain, September.

Andres M. Dominguez / Dead Lang's short-tailed blue butterfly (Leptotes pirithous) in a river with bacterial film, Los Alcornocales Natural Park, Southern Spain, September.

Jack Dykinga / Patterns in the tidal flats of the delta where the delta is swept by tidal encroachment from the Gulf of California. Evidence of the fresh water flow is observable as plant life turns green. Colorado...

Fred Olivier / Orange clownfish (Amphiprion percula) living in association with a Haddon's sea anemone (Stichodactyla haddoni), Marovo Lagoon, Solomon Islands.

Fred Olivier / Close-up shot tracking down a meltwater waterfall emerging from a glacier, Brasvellbreen Glacier, Magdalena Fjord, Svalbard, Norway, 2016.

Fred Olivier / Wide shot of the terminus of Brasvellbreen Glacier, with meltwater waterfall, Svalbard, Norway, 2016.

Morley Read / Aerial shot ascending over rainforest canopy at dawn, with the Rio Napo in background, a tributary of the Amazon, Napo Province, Ecuador, 2017.

Morley Read / Close-up of Agua rica leaf frog (Phyllomedusa ecuatoriana) eggs after 11 days development, showing beating heart and blood flowing over gills, Ecuador. Endangered.

Morley Read / Aerial tracking shot of a waterfall flowing over an old andesitic lava flow, Rio Pita Valley north of Cotopaxi Volcano, Ecuadorian Andes, 2018.

Milan Radisics / Aerial shot of yellow mineral sediments flowing into the Atlantic Ocean, near Stokkseyri, Southern Iceland, August 2018.

Milan Radisics / Aerial shot of the Austurfljot glacial river, southern Iceland, August 2018.

Milan Radisics / Aerial shot of the Austurfljot glacial river, southern Iceland, August 2018.

Milan Radisics / Aerial shot of the Hafursa glacial river running over black sand, southern Iceland, August 2018.

Milan Radisics / Aerial shot of Thjorsa glacial river, southern Iceland, August 2018.

Milan Radisics / Aerial shot of Thjorsa glacial river, southern Iceland, August 2018.

Milan Radisics / Aerial shot of Kudafljot glacial river flowing over black volcanic soil, Iceland, August 2018.

Milan Radisics / Aerial shot of Kudafljot glacial river flowing over black volcanic soil, Iceland, August 2018.