Paul Souders/ Worldfoto / Lesser Flamingo (Phoenicopterus minor) flock nesting on island, Lake Natron, Tanzania

Paul Souders/ Worldfoto / Lesser Flamingo (Phoenicopterus minor) nesting colony, Lake Natron, Tanzania

Paul Souders/ Worldfoto / Red algae and salt formations, Lake Natron, Ol Doinyo Lengai, Tanzania

Floris van Breugel / Alkali fly (Ephydra hians) underwater in protective air bubble, Mono Lake, California, USA.

Kirkendall-Spring / Soda Butte with starry nights sky, Yellowstone National Park, Wyoming, USA, June 2013.

Juan Carlos Munoz,Juan Carlos Munoz / Two Lesser flamingos (Phoeniconaias minor) one feeding the other running, Lake Nakuru NP, Rift Valley, Kenya

Juan Carlos Munoz,Juan Carlos Munoz / Lesser flamingos (Phoeiconaias minor) feeding in still lake, Lake Nakuru, Rift valley, Kenya, Africa

Pete Oxford / James's flamingos (Phoenicoparrus jamesi) Laguna Colorada, Bolivia

Owen Newman / Soda crust on Lake Natron, Tanzania, coloured red by alkali cyanobacteria, breeding site of endangered Lesser Flamingo

Owen Newman / Old nesting colony of Lesser Flamingo {Phoeniconaias minor} Lake Natron, Tanzania. Lesser flamingoes are threatened in East Africa and Lake Natron (their only breeding site) is now under threat from i...

Gerry Ellis / Soda and algae formations near shore of Lake Natron, Great Rift Valley, Tanzania

Paul Souders/ Worldfoto / Streams and Lake Natron, Ol Doinyo Lengai, Tanzania