Theo Bosboom / Patterns of algae on a limestone rock with sand, White sands beach, Causeway coast, Northern Ireland. April 2016.

Nick Hawkins / American lobster (Homarus americana) in eelgrass (Zostera marina). Nova Scotia, Canada. July

Marie Read / Horned Puffin (Fratercula corniculata) flying over a pattern of kelp and sea foam, photographed from above, St. Paul, Pribilof Islands, Alaska, USA. July.

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

Tui De Roy / Marine iguana (Amblyrhynchus cristatus) in water, Puerto Egas, Santiago Island, Galapagos

Guy Edwardes / Seaweed covered rocks with Gaada Stack in background, Foula, Shetland, Scotland, UK. August, 2016.

David Fleetham / Garibaldi (Hypsypops rubicundus) the state fish of California, in forest of giant kelp, (Macrocystis pyrifera) Catalina Island, California, USA.

Michel Roggo / Rangimairewhenua or Blue Lake, Nelson Lakes National Park, South Island, New Zealand, February 2013. Photographed for The Freshwater Project

SINCLAIR STAMMERS / Timelapse of filaments of Oscillatoria, a type of Blue green algae gliding over each other, filmed using differential interference contrast.

Pete Oxford / Marine Iguana (Amblyrhynchus cristatus) grazing on algae, Fernandina Island, Galapagos Islands, Ecuador

Roy Mangersnes / Marine iguana (Amblyrhynchus cristatus) feeding in deep water to find algae, off the coast of Fernandina island on Galapagos. April 2016. Much of the algae on coast and at shallower depths have been k...

Roy Mangersnes / Marine iguana (Amblyrhynchus cristatus) feeding in deep water to find algae, off the coast of Fernandina island on Galapagos. April 2016. Much of the algae on coast and at shallower depths have been k...