Sulfur is a necessary element and is key to the functioning of all inhabitants of the biosphere. Sulfur makes its way through the environment by a process known simply as the sulfur cycle. The sulfur cycle, which is an atmospheric cycle, is an intricate and important sequence.
This website gives basic background on the sulfur cycle, including the chemical reactions involved, its pathway of movement, organic and inorganic reservoirs, and the impact of human intervention on the cycle.