F:
FS INFO - National Forest Service Library catalog--indexing forestry and natural resources literature, including many full-text links. [U.S. Department of Agriculture (USDA), Forest Service]

N:
Nonindigenous Aquatic Species Database - A central repository for spatially referenced biogeographic accounts of introduced aquatic species. [U.S. Department of the Interior (DOI), U.S. Geological Survey (USGS), Southeast Ecological Science Center]

O:
Observing the Living Oceans from Space. Webcast - A Webcast of a presentation by Gene Feldman, NASA Goddard Space Flight Center. [U.S. Library of Congress (LOC)]

U:
United States Global Change Research Program - Coordinates and integrates federal research on changes in the global environment and their implications for society. [Multiple agencies involved]