Sulphur cycle

"Sulfur cycle, circulation of sulfur in various forms through nature. Sulfur occurs in all living matter as a component of certain amino acids. It is abundant in the soil in proteins and, through a series of microbial transformations, ends up as sulfates usable by plants" (Britannica 2020). 


Britannica, T. Editors of Encyclopaedia. "Sulfur cycle." Encyclopedia Britannica, March 11, 2020.