Microbially mediated chemical transformations in wetlands

Abstract

This chapter discusses how the microbiota mediate the cycling of carbon, nitro- gen, phosphorus and sulfur in wetlands. Wetlands have a number of characteris- tics that make them hot-spots for microbially-mediated transformation of constituents. Abundant plant life, adapted to aquatic environments represents a source of carbon (energy) to fuel microbial processes. Wetlands are sites of deposition of sediments, and often interact with ground-water, both of which are source of electron-acceptors for microbial processing. Biofilms growing on emergent and submerged plants, as well the root zone of aquatic plants, are active sites of reactions that require both oxic and anoxic zones such as coupled nitrification-denitrification. Finally, many wetlands are ephemeral, meaning the sediments undergo periodic wetting and drying, which can strongly influence nutrient cycling.