This week you learned about how Earth's important biogeochemical cycles (the water, nitrogen, phosphorus, and carbon cycles) interact with Earth's spheres. You learned that each of these important cycles circulates nutrients, energy, and matter between the biosphere, atmosphere, hydrosphere, and geosphere. You also discovered how the water cycle interacts with almost every other biogeochemical cycle & affects each of Earth's spheres.

For example, you saw that the water cycle can influence severe weather, such as hurricanes, impacting the biosphere. The carbon cycle is influenced by the biosphere because humans add extra carbon dioxide to the atmosphere. Alterations to the carbon cycle contribute to greenhouse gases building up in the atmosphere & contributing to global climate change. The geosphere alters biogeochemical systems through volcanic eruptions, which add carbon dioxide and water vapor to the atmosphere. Microbes can affect the formation of caves (part of the geosphere) through the interaction of earth's biogeochemical cycles. The carbon and sulfur cycles both cause weathering (by the formation of carbonic and sulfuric acids) and the formation of caves, altering the geosphere.

Humans have influenced all of Earth's biogeochemical cycles. Human activities have altered the carbon and nitrogen cycles, contributing to global climate change, air pollution, and water pollution. The greenhouse effect is caused by the build-up of certain gases (composed of carbon and nitrogen) in the atmosphere that trap heat at the Earth's surface.

This lesson provided you with several examples of how Earth's biogeochemical cycles interact with, affect, and are altered by, Earth's spheres.