Nick Upton / Boiling water from hot springs flowing into thermal river, with colourful growths of blue-green algae and mineral deposits at margins. Polychnitos, Lesbos / Lesvos, Greece, August 2010.

Graham Eaton / Old Manganese Mine workings at Porth Ysgo, Gwynedd, North Wales, UK, April 2010.

Ingo Arndt / Pierid Butterfly (Eurema sp) group feeding on soil minerals, Christmas Island, Indian Ocean, Territory of Australia

Pete Oxford / Rockhopper Penguins (Eudyptes chrysocome) in 'mineral clay lick', an area near near their colony which they seem to go to on a regular basis to eat some of the soil, Pebble Island, off north coast of...

Tui De Roy / White-cheeked Pintail (Anas bahamensis) ducks on mineral lake in June 1975 prior to lake being destroyed by eruptions, Fernandina Caldera, Fernandina Island, Galapagos Islands, Ecuador

Tui De Roy / Dolomite cliff with huge guillemot colony, 100,000 pairs, East Spitsbergen Island, Hinlopen Strait, Svalbard Archipelago, Norwegian Arctic