ABSTRACT
Treatment marshes remove phosphorus (P) from water and store it soils, sediments and vegetation. The size of P removal marshes is typically quite large, thus disappointing those who would hope for large removals in small footprints. A large number of internal P transfer and alteration processes occur, but only soil-building provides a net long-term storage of P. Marshes experience naturally occurring inputs of P are from surface inflows, and atmospheric deposition, which consists of both wet deposition and dryfall. P moves vertically within the action zone, driven by plant uptake, transpiration water flows, and head-driven vertical flow. This P movement is directly linked to and influenced by growth of plants, their density, and the vigor of their growth. P compounds are a significant fraction of the dry weight of wetland plants, microbes, wildlife, and soils; although they are about ten times less than nitrogen compounds. Most of the P in the soil column is structural P, both organic and inorganic.
