Environmental Engineering Reference
In-Depth Information
Phosphorus can enter the water table and ultimately travel to the oceans, where it settles on the ocean floor.
Later, through geological processes, ocean mixing, and upwelling, these rocks on the ocean floor may rise and
become new land surface, with the result that their components can reenter the terrestrial cycles.
Humans affect the phosphorus cycle by mining phosphorus-rich rocks for the purpose of processing them and
adding them to commercial inorganic fertilizers. The phosphorus is easily leached into the groundwater and
can find its way into aquatic ecosystems, where it can help promote algae and other aquatic plant growth that
can lead to overgrowth of these plants and ultimately eutrophication of the pond or lake. Phosphorus also can
be added to ecosystems by humans through the release of untreated sewage, agricultural runoff, and detergents.
Sulfur Cycle
An important component of protein and vitamins, sulfur is essential for plant and animal health. Naturally,
most sulfur is located in rocks and ocean sediments, but some is also found in the atmosphere.
