This article discusses how plants and microorganisms, until recently, have mostly controlled how much carbon dioxide is released into an ecosystem, and explains how this process works. Humans' burning of fossil fuels has upset the...

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...

An interactive lab simulation demonstrates the effects of increased carbon in the atmosphere and how that increase contributes to climate change. A data table for student records is available for download.