Wooden boardwalk and cyanobacteria thermophile formations on Geyser Hill, Upper Geyser Basin, Yellowstone National Park, UNESCO World Heritage Site, Wyoming, United States of America, North America

Water rich in blue-green algae (cyanobacteria), mineral salts and fine silica mud at the geothermal spa that owes its existence to the Svartsengi geothermal power plant, Blue Lagoon, near Reykjavik, Iceland, Polar Regions

Water rich in blue-green algae (cyanobacteria), mineral salts and fine silica mud at the geothermal spa that owes its existence to the Svartsengi geothermal power plant, Blue Lagoon, near Reykjavik, Iceland, Polar Regions

Water rich in blue-green algae (cyanobacteria), mineral salts and fine silica mud at the geothermal spa that owes its existence to the Svartsengi geothermal power plant, Blue Lagoon, near Reykjavik, Iceland, Polar Regions

Adult black-necked stilt (Himantopus mexicanus) wading and feeding in a brackish water lagoon on Floreana Island, Galapagos, UNESCO World Heritage Site, Ecuador, South America

Phytoplankton bloom off Ireland, satellite image

Aerial view, salt crust coloured red by cyanobacteria, Lake Natron, Great Rift Valley, Tanzania, Africa

Aerial view, salt crust coloured red by cyanobacteria, Lake Natron, Great Rift Valley, Tanzania, Africa

Stromatolites, Earth's oldest fossils, Hamelinbay, Northwest Australia

Stromatolites, Earth's oldest fossils, Hamelinbay, Northwest Australia