Phosphorus

About: Phosphorus is a research topic. Over the lifetime, 53120 publications have been published within this topic receiving 939731 citations. The topic is also known as: element 15 & P.

Long-term accumulation and transport of anthropogenic phosphorus in three river basins

Abstract: Global food production depends on phosphorus. Phosphorus is broadly applied as fertilizer, but excess phosphorus contributes to eutrophication of surface water bodies and coastal ecosystems1. Here we present an analysis of phosphorus fluxes in three large river basins, including published data on fertilizer, harvested crops, sewage, food waste and river fluxes2, 3, 4. Our analyses reveal that the magnitude of phosphorus accumulation has varied greatly over the past 30–70 years in mixed agricultural–urban landscapes of the Thames Basin, UK, the Yangtze Basin, China, and the rural Maumee Basin, USA. Fluxes of phosphorus in fertilizer, harvested crops, food waste and sewage dominate over the river fluxes. Since the late 1990s, net exports from the Thames and Maumee Basins have exceeded inputs, suggesting net mobilization of the phosphorus pool accumulated in earlier decades. In contrast, the Yangtze Basin has consistently accumulated phosphorus since 1980. Infrastructure modifications such as sewage treatment and dams may explain more recent declines in total phosphorus fluxes from the Thames and Yangtze Rivers3, 4. We conclude that human-dominated river basins may undergo a prolonged but finite accumulation phase when phosphorus inputs exceed agricultural demand, and this accumulated phosphorus may continue to mobilize long after inputs decline.

Phosphorus Compounds in Sequential Extracts of Animal Manures: Chemical Speciation and a Novel Fractionation Procedure

Abstract: Pollution of water bodies by phosphorus in runoff from soil amended with animal manures is one of the greatest threats to water quality in developed countries. The environmental fate of manure phosphorus is determined in part by its chemical composition, yet extraction procedures to assess this are poorly developed and provide no structural information. We used solution 31P NMR spectroscopy to quantify phosphorus compounds in sequential extracts of three contrasting manures (broiler litter, beef-cattle manure, swine manure). Using a procedure originally developed for soils, but commonly applied to manures, phosphorus was extracted sequentially with deionized water, 0.5 M NaHCO3, 0.1 M NaOH, and 0.5 M HCl. Water and NaHCO3 extracted readily soluble compounds, including phosphate, phospholipids, DNA, and simple phosphate monoesters, which are mobile in soil and biologically available. In contrast, NaOH and HCl extracted poorly soluble compounds, including phytic acid (myoinositol hexakisphosphate). The latter is immobile in soil and of limited biological availability. Based on these results, we developed a simplified two-step fractionation procedure involving extraction of readily soluble phosphorus in 0.5 M NaHCO3 followed by extraction of stable phosphorus in a solution containing 0.5 M NaOH and 50 mM EDTA. This revised procedure separates manure phosphorus into structurally defined fractions with environmental relevance and will facilitate research on this important aspect of environmental science.

The Biogeochemistry of Phosphorus Cycling and Phosphorus Availability Along a Desert Soil Chronosequence

Abstract: The biogeochemistry ofthe weathering, landscape movements, and chemical transformations of phosphorus and its availability to plants were examined in a chrono- sequence of soils developed from quartz monzonite alluvium in southern New Mexico. Total P in the soil profile decreased with increasing soil age and was removed from the ecosystem as readily as the most easily leachable base cations. Although Ca-bound forms of P decreased with increasing soil age, Ca-P remained the single largest fraction of total P in all soils. In contrast, Fe- and Al-bound P was a very small percent of total P in all soils. There was little evidence for the stabilization of P by soil organic matter within this ecosystem; both soil organic P and microbial P represented very small pools of total soil P. Phosphorus availability, measured by in situ resin bags, was not well correlated with soil age or total soil P, and P concentrations in shrub tissues did not reflect changes in forms or total amounts of soil P. The biogeochemical cycle of P in this system differs sharply from that in a more mesic, forested system, where fixation by iron and aluminum oxides and biologic activity play more dominant roles in the conservation of P within the ecosystem.

Mayan urbanism: impact on a tropical karst environment.

Abstract: From the first millennium B.C. through the 9th-century A.D. Classic Maya collapse, nonurban populations grew exponentially, doubling every 408 years, in the twin-lake (Yaxha-Sacnab) basin that contained the Classic urban center of Yaxha. Pollen data show that forests were essentially cleared by Early Classic time. Sharply accelerated slopewash and colluviation, amplified in the Yaxha subbasin by urban construction, transferred nutrients plus calcareous, silty clay to both lakes. Except for the urban silt, colluvium appearing as lake sediments has a mean total phosphorus concentration close to that of basin soils. From this fact, from abundance and distribution of soil phosphorus, and from continuing post-Maya influxes (80 to 86 milligrams of phosphorus per square meter each year), which have no other apparent source, we conclude that riparian soils are anthrosols and that the mechanism of long-term phosphorus loading in lakes is mass transport of soil. Per capita deliveries of phosphorus match physiological outputs, approximately 0.5 kilogram of phosphorus per capita per year. Smaller apparent deliveries reflect the nonphosphatic composition of urban silt; larger societal outputs, expressing excess phosphorus from deforestation and from food waste and mortuary disposal, are probable but cannot be evaluated from our data. Eutrophication is not demonstrable and was probably impeded, even in less-impacted lakes, by suspended Maya silt. Environmental strain, the product of accelerating agroengineering demand and sequestering of nutrients in colluvium, developed too slowly to act as a servomechanism, damping population growth, at least until Late Classic time.