Other
S Cool: Engery Flow and Nutrient Cycle
This website describes trophic levels, transfer of energy between trophic levels, pyramids of ecology, and nutrient cycles within the environment.
Nature Research
Nature Education: Energy Economics in Ecosystems
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...