Biogeochemical Cycles
- A brief look at the major nutrient cycles, including pictures.
- http://www.colorado.edu/GeolSci/courses/GEOL1070/chap04/chapter4.html

Water What Ifs - Water Quality and Nitrates and Phosphates
- Shows the inter-relationship of these surface water parameters.
- http://www.ncsu.edu/sciencejunction/depot/experiments/water/lessons/np/

Olympic Hands on the Land - Cycles
- From the National Park Service, animated diagrams of the water, nitrogen, and carbon cycles. Includes explanations.
- http://www.nps.gov/olym/hand/nutrition1.htm