The Nitrogen Cycle in the Yahoo! Directory

Microbial World: The Nitrogen Cycle and Nitrogen Fixation
Looks at the role of nitrogen in the biosphere.
helios.bto.ed.ac.uk/bto/microbes/nitrogen.htm
Nitrogen Cycle, The
From the online text Fundamentals of Physical Geography.
www.geog.ouc.bc.ca/physgeog/contents/9s.html
Nitrogen Fixation Research Center - National Autonomous University of Mexico
With programs in computational genomics, metabolic engineering, microbial and molecular ecology, and plant molecular biology.
www.cifn.unam.mx
Global Population and the Nitrogen Cycle (PDF)
Looks at how the distribution of nitrogen on the earth has been changed in dramatic, and sometimes dangerous, ways by modern agricultural practices.
hollandimac.chem.rochester.edu/n2cycle.pdf
Nitrogen in the Environment: Nitrogen Cycle
Offers a basic look at the nitrogen cycle.
muextension.missouri.edu/explore/envqual/wq0252.htm
Human Alteration of the Global Nitrogen Cycle: Causes and Consequences
Describes the nitrogen cycle and explores how humans have increased the amount and rate of nitrogen being cycled through the living world, soil, water, and atmosphere.
www.epa.gov/watertrain/nitroabstr.html
Nitrogen Cycle Project
Provides an improved scientific basis for developing mathematical process models that simulate the biogeochemical cycling of nitrogen in Illinois' environments.
www.sws.uiuc.edu/nitro/splash.asp
Nitrogen Fixation
Covers the range of organisms that can fix nitrogen, the physiology and anatomy of nitrogen fixation, and the ecology of nitrogen fixation.
academic.reed.edu/biology/Nitrogen