fosforkringloop

Fosforkringloop, or the phosphorus cycle, is the biogeochemical cycle that transports phosphorus through the lithosphere, hydrosphere, and biosphere. A defining feature is that phosphorus has no significant atmospheric component, so its movement is dominated by geological and biological processes that move phosphorus between rocks, soils, organisms, and aquatic sediments.

Reservoirs and fluxes include phosphate minerals in rocks and marine sediments as the largest reservoirs, with soils, biomass, and surface waters acting as more dynamic pools. Weathering releases phosphate ions into soils and streams; plants take up phosphate, animals obtain it by feeding, and decomposition or mineralization returns inorganic phosphate to the environment. Phosphate can adsorb to clay minerals, be transported in rivers to lakes and oceans, and become buried in sediments. Over geological timescales, some phosphorus becomes locked in sedimentary rocks; tectonic activity can later expose these stores again.

Humans influence the cycle primarily through mining and applying phosphate fertilizers, manure management, and wastewater discharges. These activities can markedly increase phosphate fluxes to aquatic systems, elevating the risk of eutrophication and harmful algal blooms. Because there is no significant atmospheric transport, pollution is mainly a result of surface runoff and water-body inputs rather than air deposits.

Sustainable management approaches aim to reduce losses and recover phosphorus from waste streams. Techniques include improved fertilizer efficiency, runoff reduction, and phosphorus recovery from wastewater and manure (for example, through precipitation of struvite). Closing the loop on phosphorus use is often highlighted as important for agricultural productivity and long-term resource security.