NASA
Nasa: Earth Observatory: The Carbon Cycle
Learn about the element carbon and its importance on the Earth's atmosphere and sustainability of life on the planet. Additionally, understand the role the carbon cycle plays in global climate change over time.
Vision Learning
Visionlearning: Earth Science: The Carbon Cycle: What Goes Around Comes Around
Instructional module focusing on the carbon cycle. Discussion includes the biological and geological components of how carbon moves through the atmosphere, lithosphere, and hydrosphere. Site also includes an interactive practice quiz and...
PBS
Pbs Learning Media: The Nitrogen Cycle
Nitrogen, one of the most abundant elements in the universe, is essential to life. This interactive activity adapted from the University of Alberta provides an overview of the nitrogen cycle. Includes background reading handout and...
US Geological Survey
Mercury in the Geochemical Cycle
Mercury in the geochemical cycle ultimately affects the food chain. Learn about this and its effect on the Everglades.
Other
Elmhurst College: Virtual Chembook: Carbon Cycle
A step-by-step discussion of the stages in the carbon cycle. Each step includes a diagram further explaining the processes involved, as well as pictures depicting combustion, respiration, photosynthesis, and decomposition.
University of Illinois
University of Illinois: Illinois State Water Survey: Nitrogen Cycle: Human Impact on the Nitrogen Cycle
An overview of the impact of human activities on the environment and how those actions effect the nitrogen cycle.
Biology Pages
Kimball's Biology Pages: The Nitrogen Cycle
An overview of the nitrogen cycle, covering nitrogen fixation, decay, nitrification, denitrification, and more.
BiologyWise
Biology Wise: Information About Nitrifying and Denitrifying Bacteria
Learn about the important role that nitrifying and denitrifying bacteria play in the nitrogen cycle.
University of Illinois
University of Illinois: Illinois State Water Survey: Simplified Nitrogen Cycle
A semi-technical description of the nitrogen cycle. Contains a link to an abridged version of the page along with a list of further resources on the topic.
CK-12 Foundation
Ck 12: Earth Science: Carbon Cycle and Climate
[Free Registration/Login may be required to access all resource tools.] Explains the cycle of carbon through the atmosphere, geosphere, and biosphere.
Geography 4 kids
Geography4 kids.com: Biogeochemical Cycles
Brief informational site provides the definition as well as explanation as to what Biogeochemical Cycles and what they do.
BiologyWise
Biology Wise: Carbon Cycle Diagram
Explains what the carbon cycle is and the basic steps in the cycle.
BiologyWise
Biology Wise: Carbon Oxygen Cycle
The fours stages of the carbon-oxygen cycle are described - photosynthesis, respiration, combustion, and decomposition.
BiologyWise
Biology Wise: Understanding Nitrogen Cycle With a Diagram
Describes the steps involved in the nitrogen cycle, a critical biogeochemical cycle.