This gas is released when soil is disturbed, or is released slowly into the atmosphere. Wetlands are one of the only places where N2 is produced, this is important for the ecosystem. The sulfur cycle involves the conversion of organic sulfur into H2S which is stored in soil. H2S can also be released into the atmosphere or oxidized to sulfate in the aerobic zone. Sulfate is taken up by plants or washed away by runoff.
HS production is lower in saltwater and high in freshwater.
The phosphorous cycle starts with the decomposition of particulate phosphorous and then its conversion into soluble phosphorous. Soluble phosphorous can be taken up by plants and algae or absorbed by clay particles. This chemistry in the soil is the reason that higher concentrations of P are found in effluent than in influent. Constructed wetlands are not very good at decreasing P levels. A big debate over wetlands concerns their role in the environment.