Mission 2007 - Arctic National Wildlife Refuge

This site from MIT (Massachusetts Institute of Technology) features information about the Arctic National Wildlife Refuge, which is an example of the tundra.

Nation Oceanic and Atmospheric Administration - Estuaries

The Estuaries Tutorial is an overview of estuarine habitats, the threats facing them, and efforts to monitor and protect estuaries nationwide.

University of California Museum of Paleontology ~ The World's Biomes

Desert Ecosystems

Recoverability and vulnerability in desert ecosystems. United States Geological Survey