Gulliver Media Images resources for schools.
Galleries:

Urban Ecosystems
Rainforest Ecosystems
Rivers and Riparian Fringe
Mangroves and Wetlands
Dry Schlorophyll Ecosytem
Arid Inland Ecosystem
Island Ecosystems
Reef Ecosystem

The World's Biomes  Aquatic, desert, grassland, forest and tundra.
Biomes of the World
World Biomes

Gulliver Media specialises in natural history, conservation, history, science and factual and general viewing video, television and multimedia productions.

ReefVid A resource of free coral reef video clips for educational use