Unit A

Module 1 ~ Lesson 4


You explored this essential question in this lesson:

  • How do carbon, oxygen, nitrogen, and phosphorus cycle through the biosphere?

Biogeochemical cycles are interactions between producers and consumers and between the abiotic and biotic components of an ecosystem.  Since the nutrients (carbon, oxygen, nitrogen, and phosphorus) available in the biosphere are in limited supply, they must be cycled. 

 Lesson Glossary

acid deposition: the deposit of acid to land and water through acidic rain, snow, or sleet

biogeochemical cycle: a diagram representing the movement of elements and compounds between living and non-living components of an ecosystem

carbon sink: a system that removes more carbon dioxide from the atmosphere than it releases into the atmosphere

denitrification: the process of converting nitrates in the soil into nitrogen gas

denitrifying bacteria: a type of soil bacteria that converts nitrates in soil into nitrogen gas, releasing this gas to the atmosphere

eutrophication: excessive plant growth and decay caused by an excessive amount of chemical nutrients

nitrification: the process of converting ammonia into nitrates or nitrites

nitrifying bacteria: a type of soil bacteria that converts ammonia into nitrates and nitrites

nitrogen fixation: the process of converting nitrogen gas into ammonia


Complete Unit A: Section 2 Assignment now. When you have received your feedback, complete Unit A Summative.