Marie Read / Black-necked stilts (Himantopus mexicanus) pair performing post-copulatory display (as copulation ends, the male slides off the female leaving his wings draped over her and crossing his bill with hers...

Michel Roggo / Aquatic plants on the river bed of the Okavango river, Okavango Delta, Botswana, June 2014 . Photographed for The Freshwater Project

Linda Pitkin / 2020VISION / White clawed crayfish (Austropotamobius pallipes) on river bed, viewed underwater, River Leith, Cumbria, England, UK, September 2012.

Linda Pitkin / 2020VISION / Brown trout (Salmo trutta) fry on river bed, Cumbria, England, UK, September.

Juan Carlos Munoz / Aerial view dry river bed in the Namib desert, Sossusvlei, Sesriem, Namibia, August 2008

Laurie Campbell / Brown trout (Salmo trutta) resting on river bed near the Aigas Field Studies Centre, Inverness-shire, Scotland, July

Todd Mintz / Sockeye salmon (Oncorhynchus nerka) split level view of salmon on river bed, annual spawning run, Adams River, British Columbia, Canada, October

Linda Pitkin / 2020VISION / Freshwater pearl mussels (Margaritifera margaritifera) on river bed, Ennerdale Valley, Lake District NP, Cumbria, England, UK, October 2011

Willem Kolvoort / Aquatic plants on river bed, River Black Drim, Albania, Eastern Europe, May 2009

Michel Roggo / Underwater landscape in Hongrin River with ice on the river bed and surface in winter. Fribourg, Gruyre, Switzerland, December

David Woodfall / Villagers living in former river bed now dry due to siltation, complex effects of climate change, Ganges delta, Bangladesh, November 2008

Solvin Zankl / Aquatic larva of the Long-tailed / Tisza mayfly(Palingania longicauda) shoveling and digging. These larvae live for several years in the clay of the river bed of the Tisza River. Hungary, Central Euro...