ABSTRACT
Sulfur is a ubiquitous element present in many forms in the environment, and its biogeochemistry is an important regulator of redox chemistry, with strong linkages to nutrient cycling, trace-metal redox behavior, microbiological energetics, plant growth, and mineralogical composition of soils and sediments. The large inputs of organic matter into wetland soils, along with aerobic and anaerobic zones where sulfur transformation occurs, allow sulfur to play a critical role in the biogeochemistry of wetlands. Sulfur has other notable similarities to the nitrogen cycle in that species in both cycles range from oxidized inorganic and reduced forms to gaseous reduced and oxidized species. Sulfur transformations are complex due to the number of redox states for sulfur and the rapid transformations that can occur. In salt marshes and brackish swamps, high concentrations of soil and sediment sulfur are observed. In mineral-based systems, particularly those with high iron, the majority of total sulfur is often present as reduced inorganic sulfur minerals.
