ABSTRACT
Phosphorus (atomic weight 30.974) is the 12th most abundant element in the lithosphere. Phosphorus concentration in the earth’s crust is reported to be approximately 0.1%. Under natural conditions, weathering of minerals releases phosphorus into the environment. The phosphorus cycle is dynamic and involves interaction or exchange between biotic and abiotic pools. Phosphorus inputs through atmospheric deposition and weathering of natural minerals can maintain wetlands and aquatic systems enriched with phosphorus and can signi cantly impact trophic conditions. On any given landscape, phosphorus transfer is typically from uplands to wetlands, and then to the aquatic environment (Figure 9.1). Phosphorus loads from uplands to many aquatic systems rapidly increased during the industrial and green revolution as a result of heavy fertilizer use and the demand to produce more food to meet the demand of the population explosion. Converting wetlands to agricultural and urban lands decreased the capacity of existing wetlands to retain phosphorus. This has resulted in phosphorus enrichment of many lakes, rivers, estuaries, and coastal waters. At the landscape level, wetlands can function as buffers for phosphorus retention between uplands and adjacent aquatic systems such as lakes, streams, and estuaries. Thus, it is important to understand the transfer of phosphorus from uplands to wetlands, and the biogeochemical processes regulating its availability and retention in wetlands.
