Showing papers on "Phosphorus published in 2012"

Effects of Phosphate Binders in Moderate CKD

Abstract: Some propose using phosphate binders in the CKD population given the association between higher levels of phosphorus and mortality, but their safety and efficacy in this population are not well understood. Here, we aimed to determine the effects of phosphate binders on parameters of mineral metabolism and vascular calcification among patients with moderate to advanced CKD. We randomly assigned 148 patients with estimated GFR=20–45 ml/min per 1.73 m 2 to calcium acetate, lanthanum carbonate, sevelamer carbonate, or placebo. The primary endpoint was change in mean serum phosphorus from baseline to the average of months 3, 6, and 9. Serum phosphorus decreased from a baseline mean of4.2mg/dlinbothactiveandplaceboarmsto3.9mg/dlwithactivetherapyand4.1mg/dlwithplacebo (P=0.03). Phosphate binders, but not placebo, decreased mean 24-hour urine phosphorus by 22%. Median serum intact parathyroid hormone remained stable with active therapy and increased with placebo (P=0.002). Active therapy did not significantly affect plasma C-terminal fibroblast growth factor 23 levels. Active therapy did, however, significantly increase calcification of the coronary arteries and abdominal aorta (coronary: median increases of 18.1% versus 0.6%, P=0.05; abdominal aorta: median increases of 15.4% versus 3.4%, P=0.03). In conclusion, phosphate binders significantly lower serum and urinary phosphorus and attenuate progression of secondary hyperparathyroidism among patients with CKD who have normal or near-normal levels of serum phosphorus; however, they also promote the progression of vascular calcification. The safety and efficacy of phosphate binders in CKD remain uncertain.

The Role of Plants in the Effects of Global Change on Nutrient Availability and Stoichiometry in the Plant-Soil System

Abstract: The impact on nitrogen ([N][1]) and phosphorus ([P][2]) cycles of human activity is a growing concern and has several causes and consequences ([MacDonald et al., 2011][3]; [Penuelas et al., 2012][4]; [Sardans et al., 2012b][5]). Carbon ([C][6]) inputs by human CO2 emissions and [N][1] inputs from

Red phosphorus: An elemental photocatalyst for hydrogen formation from water

Abstract: A novel property of red phosphorus for visible light driven photocatalytic H 2 formation from water by photogenerated electrons has been discovered. The detection of hydroxyl radicals and results from photoconductivity measurements confirmed the photogeneration of electrons and holes. Theoretical calculations also indicated that the reduction of water by photogenerated electrons would be energetically possible. A P-type semiconductor behavior of red phosphorus was observed. Our findings may provide insights for developing phosphorus-based photocatalysts.

Electrochemical Activity of Black Phosphorus as an Anode Material for Lithium-Ion Batteries

Abstract: Black phosphorus (black P), which is a promising candidate as an anode material for lithium-ion batteries, was synthesized by a high-pressure and high-temperature (HPHT) method from white and red phosphorus. The study revealed the electrochemical activity of pure black P under different pressures and temperatures systematically. The sample shows higher crystallinity and purity by the HPHT method. Lithium-ion batteries containing black phosphorus as anode materials exhibited a high specific capacity and excellent cycling performance. Black phosphorus obtained from white phosphorus exhibited the highest first discharge and charge capacities of 2505 and 1354 mAh·g–1 at 4 GPa and 400 °C and that obtained from red phosphorus exhibited the highest first discharge and charge capacities of 2649 and 1425 mAh·g–1 at 4.5 GPa and 800 °C. Black P was characterized by X-ray diffraction, Raman microscopy, scanning electron microscopy, and high-resolution transmission electron microscopy.

Changes of nitrogen and phosphorus loads to European seas

Abstract: During the last decades human activity has altered the natural cycle of nitrogen and phosphorus on a global scale, producing significant emissions to waters. In Europe, the amount of nutrients discharged from rivers to coastal waters as well as the effects of mitigation measures in place are known only partially, with no consistent temporal and spatial cover. In this study, we quantify the loads and concentration of nitrogen and phosphorus discharged in the European seas over the period 1985–2005, and we discuss their impact on coastal ecosystems. To support our analysis, a catchment database covering the whole of Europe was developed together with data layers of nutrients diffuse and point sources, and the statistical model green was used to estimate the annual loads of nitrogen and phosphorus discharged in all European seas. The results of this study show that during the last 20 years, Europe has discharged 4.1–4.8 Tg yr−1 of nitrogen and 0.2–0.3 Tg yr−1 of phosphorus to its coastal waters. We show that beside the North Sea and part of the Baltic Sea, annual nutrient exports have not changed significantly, in spite of the implementation of measures to reduce nutrient sources, and that the N : P ratio has increased steadily, especially in the North, Mediterranean and Atlantic seas. The response of river basins to changes in inputs was not linear, but influenced by climatic variations and nutrients previously accumulated in soils and aquifers. An analysis of the effects of European environmental policies shows that measures to reduce phosphorus were more successful that those tackling nitrogen and that policies aimed at point sources were more effective or more effectively implemented than those controlling pollution from diffuse sources. The increase of the N : P ratio could fuel eutrophication in N-limited coastal ecosystems, reducing biodiversity and the ecosystem's resilience to future additional anthropogenic stress, such as climate change.

The European phosphorus balance

Abstract: Phosphorus (P) is considered a potentially critical resource because reserves are limited; it is required by all creatures, and it cannot be substituted. In this paper a substance flow analysis of phosphorus for the former 15 member states of the European Community (EU15) is presented. In order to consider the heterogeneity of the database with regard to quantity and quality all data are considered with uncertainty ranges. Error propagation and data reconciliation are performed applying the software STAN. Comparing basic and reconciled data shows that the result is reliable enough to allow the following conclusions: the system of the EU15 is largely dependent on imports of phosphorus. Net per capita consumption in the EU15 is 4.7 kgP/yr of which only 1.2 kgP/yr reach the consumer. The main losses are a net accumulation in agricultural soils (2.9 kgP/yr), followed by losses to landfills (1.4 kgP/yr) and to the hydrosphere (0.55 kgP/yr). Only 0.77 kgP/yr are recycled. Optimizing phosphorus fertilization, collecting and recycling of phosphorus-rich wastes, increasing the connection of households to sewer systems, and implementing tertiary wastewater treatment comprehensively could reduce Europe's import dependence on phosphorus significantly.

Humic acid application alleviate salinity stress of bean (Phaseolus vulgaris L.) plants decreasing membrane leakage

Abstract: The effect of varying humic acid supplies (0, 0.05 and 0.1% w/w) on some agro-physiological properties and ionic balance of bean plants in different salt source and doses were investigated. Plants were treated with eight salt sources [sodium chloride (NaCl), sodium sulphate (Na2SO4), calcium chloride (CaCl2), calcium sulphate (CaSO4), potassium chloride (KCl), potassium sulphate (K2SO4), magnesium chloride (MgCl2) and magnesium sulphate (MgSO4)] in four different concentrations (0, 30, 60, and 120 mM doses) for 60 days in a growth media. The highest salt doses; 120 mM of NaCl, CaCl2, MgCl2 and KCl2 at no humic acid applications caused plant death, but no plant death was obtained in humic acid application (0.05 and 0.1%) doses in all of the salt types and doses except for CaCl2. Total chlorophyll and nitrate contents of plants decreased with increasing salt doses, but were negatively related to humic acid application doses. Proline contents of plant were increased with increasing salt doses and the highest value was obtained for NaCl application. The effects of salt concentrations in nitrogen and phosphorus content of plants were significant. Humic acid added to saline soil significantly improved the variables affected by high salinity and also increased plant nitrate, nitrogen and phosphorus, reduced soil electricity conductivity, proline and electrolyte leakage of plant, enhanced plant root and shoot dry weight by allowing nutrients and water to be released to the plant as needed. The result suggested that humic acid have great potential in alleviating salinity stress on plant growth and growth parameter in saline soils of arid and semi-arid areas. This humic acid appeared to be highly effective for soil conditioners in vegetable growth, to improve crop tolerance and growth saline conditions. Key words: Arid soil, electrolyte leakage, leaf area, nitrate, proline, total chlorophyll, salt stress.

Incidence and diversity of phosphate-solubilising bacteria are linked to phosphorus status in grassland soils

Abstract: The extent to which soil phosphorus (P) status affected the incidence of soil phosphate-solubilising bacteria (PSB) and their taxonomic abundance and diversity was examined at three long-term fertiliser trials (Whatawhata, Winchmore and Ballantrae) in New Zealand Bacteria were isolated from rhizosphere (ryegrass and clover) and non-rhizosphere soils differing in P status The P-solubilising phenotype was determined on agar supplemented with sparingly-soluble mineral phosphates (Ca 2 OH(PO 4 ) 3 and CaHPO 4 ) The frequency of P-solubilisation in the bacterial population was significantly greater ( P P Actinobacteria , Pseudomonadaceae and Moraxellaceae The phylogenetic composition of PSB differed significantly ( P

Carbon trading for phosphorus gain: the balance between rhizosphere carboxylates and arbuscular mycorrhizal symbiosis in plant phosphorus acquisition

Abstract: Two key plant adaptations for phosphorus (P) acquisition are carboxylate exudation into the rhizosphere and mycorrhizal symbioses. These target different soil P resources, presumably with different plant carbon costs. We examined the effect of inoculation with arbuscular mycorrhizal fungi (AMF) on amount of rhizosphere carboxylates and plant P uptake for 10 species of low-P adapted Kennedia grown for 23 weeks in low-P sand. Inoculation decreased carboxylates in some species (up to 50%), decreased plant dry weight (21%) and increased plant P content (23%). There was a positive logarithmic relationship between plant P content and the amount of rhizosphere citric acid for inoculated and uninoculated plants. Causality was indicated by experiments using sand where little citric acid was lost from the soil solution over 2 h and citric acid at low concentrations desorbed P into the soil solution. Senesced leaf P concentration was often low and P-resorption efficiencies reached >90%. In conclusion, we propose that mycorrhizally mediated resource partitioning occurred because inoculation reduced rhizosphere carboxylates, but increased plant P uptake. Hence, presumably, the proportion of plant P acquired from strongly sorbed sources decreased with inoculation, while the proportion from labile inorganic P increased. Implications for plant fitness under field conditions now require investigation.

Recovery of phosphorus as struvite from sewage sludge ash

Abstract: Phosphorus (P) is an element vital for all living organisms, yet the world's reserves of phosphate rock are becoming depleted. This study investigated an effective P recovery method from sludge ash via struvite precipitation. Results showed that more than 95% of the total P content was extracted from sludge ash by applying 0.5 mol/L HCl at a liquid/solid ratio of 50 mL/g. Although heavy metal leaching also occurred during P extraction, cation exchange resin efficiently removed the heavy metals from the P-rich solution. Orthogonal tests showed that the optimal parameters for P precipitation as struvite would be a Mg:N:P molar ratio of 1.6:1.6:1 at pH 10.0. X-ray diffraction analysis validated the formation of struvite. Further investigations revealed that the harvested precipitate had a high struvite content (97%), high P bioavailability (94%), and low heavy metal content, which could be considered a high quality fertilizer.

Dynamic Changes in the Distribution of Minerals in Relation to Phytic Acid Accumulation during Rice Seed Development

Abstract: Phytic acid (inositol hexakisphosphate [InsP6]) is the storage compound of phosphorus in seeds. As phytic acid binds strongly to metallic cations, it also acts as a storage compound of metals. To understand the mechanisms underlying metal accumulation and localization in relation to phytic acid storage, we applied synchrotron-based x-ray microfluorescence imaging analysis to characterize the simultaneous subcellular distribution of some mineral elements (phosphorus, calcium, potassium, iron, zinc, and copper) in immature and mature rice (Oryza sativa) seeds. This fine-imaging method can reveal whether these elements colocalize. We also determined their accumulation patterns and the changes in phosphate and InsP6 contents during seed development. While the InsP6 content in the outer parts of seeds rapidly increased during seed development, the phosphate contents of both the outer and inner parts of seeds remained low. Phosphorus, calcium, potassium, and iron were most abundant in the aleurone layer, and they colocalized throughout seed development. Zinc was broadly distributed from the aleurone layer to the inner endosperm. Copper localized outside the aleurone layer and did not colocalize with phosphorus. From these results, we suggest that phosphorus translocated from source organs was immediately converted to InsP6 and accumulated in aleurone layer cells and that calcium, potassium, and iron accumulated as phytic acid salt (phytate) in the aleurone layer, whereas zinc bound loosely to InsP6 and accumulated not only in phytate but also in another storage form. Copper accumulated in the endosperm and may exhibit a storage form other than phytate.

Life cycle assessment of phosphorus alternatives for Swedish agriculture

Abstract: Phosphorus is an important nutrient in plant cultivation. Global reserves of phosphate rock worth mining are limited. Reuse of phosphorus in wastewater is therefore important. This LCA study assessed the environmental impact of four ways to supply Swedish agriculture with phosphorus fertiliser of acceptable quality as regards cadmium content: mineral fertiliser; certified sewage sludge; struvite (MgNH4PO4·6H2O) precipitated from wastewater; and phosphorus recovered from sludge incineration. These were examined with respect to impacts on global warming, eutrophication, energy demand and cadmium flows to farmland. The functional unit chosen was 11 kg P (25.2 kg P2O5) to agricultural land, which was the average phosphorus output (removal with harvest) per hectare from Swedish farmland in 2007. Using sewage sludge directly on farmland was the most efficient option in terms of energy and emissions of greenhouse gases, but also added most cadmium to the soil. Phosphorus recovery from incinerated sludge was the most energy demanding option and gave most emissions of greenhouse gases. Despite great concerns about cadmium in Swedish fertilisers and sludge, it was found that almost no regular analyses for cadmium are made on imported food by the authorities, although food imports are constantly increasing. Total imports of cadmium with food are therefore unknown.

Phosphorus as a Lewis Acid: CO2 Sequestration with Amidophosphoranes

Abstract: The frustrated Lewis pair system consisting of 2 equiv of 2,2,6,6-tetramethylpiperidine (TMP) and tris(pentafluorophenyl)borane [B(C6F5)3] activates carbon dioxide to form a boratocarbamate-TMPH ion pair. In the presence of triethylsilane, this species is converted to a silyl carbamate and the known ion pair [TMPH][HB(C6F5)3], which recently was shown to react with CO2 via transfer of the hydride from the hydridoborate to form the formatoborate [TMPH]+[HC(O)OB(C6F5)3]. In the presence of extra B(C6F5)3 (0.1-1.0 equiv) and excess triethylsilane, the formatoborate is rapidly hydrosilated to form a formatosilane and regenerate [TMPH][HB(C6F5)3]. The formatosilane in turn is rapidly hydrosilated by the B(C6F5)3/Et3SiH system to CH4, with (Et3Si)2O as the byproduct. At low [Et3SiH], intermediate CO2 reduction products are observed; addition of more CO2/Et3SiH results in resumed hydrosilylation, indicating that this is a robust, living tandem catalytic system for the deoxygenative reduction of CO2 to CH4. The utilization of carbon dioxide as a sustainable and nontoxic C1 feedstock for the production of value-added chemical products such as carboxylic acids or fuels such as methanol and methane is of current interest. The high thermodynamic stability of CO2 necessitates its catalytic activation and coupling to a thermodynamic driver for efficient conversion. Transition-metal-based catalysts have played a dominant role in CO2 conversion, but recently, an increasing number of organocatalytic CO2 reduction schemes have emerged. For example, N-heterocyclic carbenes (NHCs) reversibly form zwitterionic adducts NHC ·CO2 that are considered key intermediates in the reductive deoxygenation of CO2 using diphenylsilane as a sacrificial reducing agent, affording CH3OH upon workup. In this context, activation of CO2 by transition-metal-free “frustrated Lewis pairs” (FLPs) has led to the development of stoichiometric reductions of CO2 to CH3OH. Here, the FLPs form bridging carboxylate species that can accept hydrogen from ammonia borane or via a thermally driven, multistep self-reduction in which the key step is a reversible B-H bond addition of hydridotris(pentafluorophenyl)borate to one CdO double bond of CO2, affording the formatoborate anion [HC(O)OB(C6F5)3]. Ultimately, hydrolysis of CH3O-LA (LA ) BX3 or AlX3) is required in order to obtain methanol. Boron-hydrogen bond addition to CO2 mediated by phosphonium or ammonium borate ion pairs formed via FLP hydrogen splitting thus offers a potential entry point into catalytic CO2 fixation in the presence of a suitable reducing agent (oxygen acceptor). We have shown that perfluoroarylboranes are excellent catalysts for the reductive hydrosilylation of carbonyl functions and C-O bonds, a potentially useful reaction for subsequent steps in the reductive deoxygenation of CO2 to CH4. The ammonium hydridoborate ion pair 1 formed by treatment of the FLP B(C6F5)3/2,2,6,6-tetramethylpiperidine (TMP) and hydrogen (32 M, C6D5Br) reacted with CO2 (2-4 atm) in the presence of Et3SiH (18 equiv) at 56 °C to afford the previously reported formatoborate 2 exclusively (see Scheme 1). The reaction was monitored by 1H and 19F NMR spectroscopy, and integration versus an internal standard (C6H5CF3, 9 mM) revealed that no Et3SiH was consumed. Thus, although the formation of 2 is reversible, there does not appear to be sufficient free B(C6F5)3 present under these conditions to activate silane for further reduction of 2. Accordingly, we carried out a reaction under identical conditi ns with an additional 1.0 equiv of B(C6F5)3 (relative to 1) present. This resulted in the immediate and complete conversion of 2 back into 1 at room temperature and the appearance of the products of CO2 hydrosilylation. Further monitoring of the reaction by 1H and 19F NMR spectroscopy at 56 °C sho ed t at silane was gradually consumed and that CH4 along with 2 equiv of (Et3Si)2O were formed as the ultimate reaction products. Minor amounts of bis(triethylsilyl)acetal, (Et3SiO)2CH2, (∼10%) were also present. Interestingly, 1 and B(C6F5)3 were the only boron-containing compounds detectable during the reaction but diminished in favor of a new species, 3, upon complete silane consumption. At the same time, the characteristic signals of HCO2SiEt3, {Et3SiO}2CH2, and Et3SiOCH3 in C6D5Br became evident in the 1H NMR spectra. Upon addition of further silane equivalents and pressurization with fresh CO2, these partially reduced intermediates were depleted and methane formation resumed, indicating a “living” catalytic system. Scheme 1 Published on Web 07/15/2010 10.1021/ja105320c  2010 American Chemical Society 10660 9 J. AM. CHEM. SOC. 2010, 132, 10660–10661 Reaction of FLP with H2/CO2 JACS 2010, 132, 10660. Introduction 3: FLP other than Group 13/15

Oxygen isotopes unravel the role of microorganisms in phosphate cycling in soils.

Abstract: Phosphorus (P) is considered the ultimate limiting nutrient for plants in most natural systems and changes in the distribution of inorganic and organic P forms during soil development have been well documented. In particular, microbial activity has been shown to be an important control on P cycling but its contribution in building up the pool of plant-available P during soil development is still poorly quantified. To determine the importance of different biological processes on P cycling, we analyzed the isotopic composition of oxygen in phosphate (δ 18 O-Pi) from the parent material, soil microorganisms, the available P pool, and from the vegetation along a 150-year soil chronosequence of a glacier forefield. Our results show that at all sites, δ 18 O-Pi of microbial Pi is within the range expected for the temperature- dependent equilibrium between phosphate and water. In addition, the isotopic signature of available Pi is close to the signature of microbial Pi, independently of the contribution of parent material Pi, vegetation Pi or Pi released from organic matter mineralization. Thus, we show that phosphate is cycled through soil microorganisms before being released to the available pool. This isotopic approach demonstrates for the first time in the field and over long time scales, and not only through controlled experiments, the role of the microbial activity in cycling of P in soils.

Prospectus of phosphate solubilizing microorganisms and phosphorus availability in agricultural soils: A review

Abstract: Phosphate solubilizing microorganisms (PSMs) offer an ecologically acceptable mean for converting insoluble phosphate to soluble forms making them available for plants to absorb. Several bacterial strains (Pseudomonas, Bacillus, Rhizobium and Enterobacter) and fungal strains (Aspergillus and Penicillium) have so far been recognized as powerful phosphate solubilizers. Insoluble phosphates are converted into available forms by phosphate solubilizing microorganisms via the process of acidification, chelation, exchange reactions and production of organic acid. Though phosphorus is found to be a limiting factor in many soils, application of PSMs as biofertilizers or bioconverters for solubilizing fixed phosphorus has not yet been successfully practiced. In this context, isolation, identification and characterization of soil PSMs are considered to be effective in broadening the spectrum of phosphate solubilizers available for field application. Key words: Phosphate solubilization, insoluble phosphate, organic acid, Phosphate solubilizing microorganisms (PSMs).

Phosphorus : chemistry, biochemistry and technology

Abstract: Introduction and Historical Background General Overview Historical Survey Classification and Nomenclature of P Compounds Literature of Phosphorus Chemistry Distribution and Environment General Occurrence Phosphate Mineral Deposits Environmental Phosphorus Atomic and Molecular Properties Atomic Properties Equilibria and Stereochemistry Types of Reaction Bond Strengths and Bond Lengths Phosphides of Non-Metals The Element Oxides Sulphides Hydrides Nitrides Halides Borides Carbides Silicides Oxyphosphorus Compounds Introduction Phosphoric and Polyphosphoric Acids Orthophosphates Condensed Phosphates Substituted Phosphates Phosphate Esters Complex Phosphates and Space-Containing Structures References Carbophosphorus Compounds Introduction and Nomenclature Phosphines Phosphine Oxides Phosphonous and Phosphinous Halides Phosphonic and Phosphinic Halides Phosphonous and Phosphinous Acids Phosphonic and Phosphinic Acids Phosphites Phosphonium Salts Phosphonium Ylides Carbenes and Carbanions Phosphoranes Phosphorides Compounds with one- and Two-Connected P Atoms Compounds with Three-Connected P Atoms Cyaphides and Cyanides Polyphosphines Polyphosphonates and Polyphosphinates Diphosphenes and Related PV-PIII Compounds Saturated Rings with Phosphorus and Carbon Unsaturated Rings with Phosphorus and Carbon Condensed Rings and Cages with Phosphorus and Carbon Rings and Cages with Phosphorus, Carbon and Oxygen Azaphosphorus Compounds Nomenclature Compounds of Phosphorus, Nitrogen and Hydrogen Phosphazanes with P-NH Linkages Phosphazanes with P-N-C Linkages Phosphazanes with P-N and P-C Linkages Hydrazides and Azides Polymeric Phosphazanes and Cyclic Compounds Cyclic Phosphazenes Linear Phosphazenes Monophosphazenes Two- and Three-Connected Phosphazenes Phosphazynes Chapter 8 Metallophosphorus Compounds Metal Phosphides: Introduction Metal-Rich Phosphides MXPYX > Y Ionic Phosphides Phosphides with Complex Anions Monophosphides Phosphorus-Rich Phosphides Miscellaneous Phosphides Metallophosphines and Metallophosphites Metallophosphorus Coordination Complexes Complexes with M-P-C Bonds Complexes with M-P-H Bonds Complexes with M-P-Halogen Bonds Complexes with P-M, P-O and P-C Bonds Bonding Effects in Metal Complexes Complexes with P-P Bonds Complexes with Pn Units Bonded To M Atoms Diphosphene and Phosphaalkene Complexes Metallophosphene and Metallophosphyne Complexes Metal Complexes of Cyclic P and C Compounds Metal Complexes OF P-N and P/N Compounds Polymers with Metal-Phosphorus Linkages Miscellaneous Complexes Containing P and M Atoms Compounds with p-Block Elements Phosphorus and Boron Phosphorus and Aluminium1,2 Phosphorus and Gallium Phosphorus and Indium Phosphorus and Silicon Phosphorus and Germanium Phosphorus and Tin Phosphorus and Lead Phosphorus and Arsenic, Antimony or Bismuth Phosphorus and Sulphur Phosphorus and Selenium or Tellurium Biopolymers and Phospho-Bioassemblies Polysaccharides Proteins Lipids Nucleic Acids and Nucleotides Biophosphorus Chemistry Body Composition and General Biochemical Background Nutritional Aspects of Phosphorus Energy Carriers Enzymes Essential Bio Processes Polynucleotide Functions Phosphonate Metabolism Applications of Phosphorus Compounds Phosphoric Acid Fertilisers Animal Foodstuffs Food Technology Detergents Water Treatment Metal Surface Treatment Pigments and Dyestuffs Glasses Phosphoceramic Constructional Materials Industrial Phosphate Esters Pesticides Medicinal Compounds and Toxic Esters Dental and Medical Materials Synthetic Polymers and Fire Retardants Pyrotechnics Natural Products Catalysts and Synthetic Reagents Metallurgy and Metal Phosphides Electronic, Electrical and Related Materials Special Topics Hydrogen Bonding Stereochemistry and Isomerism Pseudorotation and the Trigonal Bipyramid Free Radicals and Short-Lived Species Radioactivity and Radiochemistry Migrations, Rearrangements and other Reactions Analysis and Characterisation Chemical Methods Physical Methods Biopolymer Analysis Appendices Atomic Data for the Elements Hazards of Phosphorus Compounds Properties of White Phosphorus P4 Properties of 'Red' Phosphorus Pn Properties of Phosphine PH3 Properties of Orthophosphoric Acid, H3PO4 Abbreviations and Symbols Conversion Factors Shortened Journal Nomenclature

High microcystin concentrations occur only at low nitrogen-to-phosphorus ratios in nutrient-rich Canadian lakes

Abstract: Although the cyanobacterial toxin microcystin has been detected in Canadian fresh waters, little is known about its prevalence on a national scale. Here, we report for the first time on microcystin...

Atmospheric phosphorus deposition may cause lakes to revert from phosphorus limitation back to nitrogen limitation.

Abstract: Recent findings indicate that increased atmospheric deposition of nitrogen of human origin has caused changes in the pattern of ecological nutrient limitation in lakes in the northern hemisphere. An increase in the nitrogen to phosphorus ratio, and hence a shift from pristine nitrogen limitation to human-induced phosphorus limitation of phytoplankton growth, seems to have been driven by deposition of atmospheric nitrogen. These findings challenge the classical paradigm of lake phytoplankton productivity being naturally limited by phosphorus availability. However, atmospheric phosphorus deposition may also be highly relevant. Here we show how dissolved inorganic nitrogen concentration has decreased in the Pyrenean lake district over recent decades, despite there being an increase in deposition of atmospheric nitrogen. This is related to an increased atmospheric phosphorus load in the lake water, as a result of higher atmospheric inputs. These changes are causing phytoplankton to revert from being phosphorus-limited to being nitrogen-limited.

Engineering phosphorus metabolism in plants to produce a dual fertilization and weed control system

Abstract: Lopez-Arredondo and Herrera-Estrella produce transgenic plants that express a bacterial phosphite-oxidoreductase gene to enable use of phosphite as a sole phosphorus source. This technology could reduce the amount of non-renewable phosphorus used as fertilizer and control weeds.

Anoxia-induced release of colloid- and nanoparticle-bound phosphorus in grassland soils.

Abstract: Particle-facilitated transport is a key mechanism of phosphorus (P) loss in agroecosystems. We assessed contributions of colloid- and nanoparticle-bound P (nPP; 1–415 nm) to total P released from grassland soils receiving biannual poultry litter applications since 1995. In laboratory incubations, soils were subjected to 7 days of anoxic conditions or equilibrated at pH 6 and 8 under oxic conditions and then the extract was size fractionated by differential centrifugation/ultrafiltration for analysis of P, Al, Fe, Si, Ti, and Ca. Selected samples were characterized by transmission electron microscopy–energy dispersive spectroscopy (TEM-EDS) and field flow fractionation (FFF-ICP-MS). Particles released were present as nanoaggregates with a mean diameter of 200–250 nm, composed of ∼50-nm aluminosilicate flakes studded with Fe and Ti-rich clusters (<10 nm) that contained most of the P detected by EDS. Anoxic incubation of stimulated nPP release with seasonally saturated soils released more nPP and Fe2+(aq) th...