Showing papers on "Phosphorus published in 2010"

Biological stoichiometry of plant production: metabolism, scaling and ecological response to global change

Abstract: Biological stoichiometry theory considers the balance of multiple chemical elements in living systems, whereas metabolic scaling theory considers how size affects metabolic properties from cells to ecosystems. We review recent developments integrating biological stoichiometry and metabolic scaling theories in the context of plant ecology and global change. Although vascular plants exhibit wide variation in foliar carbon:nitrogen:phosphorus ratios, they exhibit a higher degree of 'stoichiometric homeostasis' than previously appreciated. Thus, terrestrial carbon:nitrogen:phosphorus stoichiometry will reflect the effects of adjustment to local growth conditions as well as species' replacements. Plant stoichiometry exhibits size scaling, as foliar nutrient concentration decreases with increasing plant size, especially for phosphorus. Thus, small plants have lower nitrogen:phosphorus ratios. Furthermore, foliar nutrient concentration is reflected in other tissues (root, reproductive, support), permitting the development of empirical models of production that scale from tissue to whole-plant levels. Plant stoichiometry exhibits large-scale macroecological patterns, including stronger latitudinal trends and environmental correlations for phosphorus concentration (relative to nitrogen) and a positive correlation between nutrient concentrations and geographic range size. Given this emerging knowledge of how plant nutrients respond to environmental variables and are connected to size, the effects of global change factors (such as carbon dioxide, temperature, nitrogen deposition) can be better understood.

Phosphorus demand for the 1970-2100 period: A scenario analysis of resource depletion

Abstract: The phosphorus (P) cycle has been significantly altered by human activities. For this paper, we explored the sustainability of current P flows in terms of resource depletion and the ultimate fate of these flows. The analysis shows that rapid depletion of extractable phosphate rock is not very likely, in the near term. Under best estimates, depletion would be around 20–35%. In worst case scenarios, about 40–60% of the current resource base would be extracted by 2100. At the same time, production will concentrate in Asia, Africa and West Asia, and production costs will likely have increased. As there are no substitutes for phosphorus plant nutrients in agriculture, arguably even partial depletion of P resources may in the long run be relevant for the sustainability of agriculture. Consumption trends lead to large flows of phosphorus to surface water and a considerable build-up of phosphorus in agricultural soils in arable lands. This may allow a reduction in future P fertiliser application rates in crop production. Results also indicate a global depletion of P pools in soils under grassland, which may be a threat to ruminant production.

The evolution of the marine phosphate reservoir

Abstract: Phosphorus is generally thought to be a limiting nutrient of primary productivity in the oceans, and is important in regulating the redox state of the ocean–atmosphere system. Planavsky et al. use the ratio of phosphorus to iron in iron-oxide-rich sedimentary rocks through time to evaluate the evolution of the marine phosphate reservoir. They find relatively constant phosphate concentrations during the past 542 million years of Earth's history. The data are also indicative of high dissolved phosphate concentrations in the aftermath of the 'snowball Earth' glaciations around 700 million years ago, which could have led to high rates of primary productivity, organic carbon burial and an increase in atmospheric oxygen levels, paving the way for the rise of metazoan life. Phosphorus is a biolimiting nutrient that is important in regulating the redox state of the ocean–atmosphere system. Here, the ratio of phosphorus to iron in iron-oxide-rich sedimentary rocks through time has been used to evaluate the evolution of the marine phosphate reservoir. Phosphate concentrations have been relatively constant over the past 542 million years of Earth's history, but were high in the aftermath of the 'snowball Earth' glaciations some 750 to 635 million years ago, with implications for the rise of metazoan life. Phosphorus is a biolimiting nutrient that has an important role in regulating the burial of organic matter and the redox state of the ocean–atmosphere system1. The ratio of phosphorus to iron in iron-oxide-rich sedimentary rocks can be used to track dissolved phosphate concentrations if the dissolved silica concentration of sea water is estimated2,3,4,5. Here we present iron and phosphorus concentration ratios from distal hydrothermal sediments and iron formations through time to study the evolution of the marine phosphate reservoir. The data suggest that phosphate concentrations have been relatively constant over the Phanerozoic eon, the past 542 million years (Myr) of Earth’s history. In contrast, phosphate concentrations seem to have been elevated in Precambrian oceans. Specifically, there is a peak in phosphorus-to-iron ratios in Neoproterozoic iron formations dating from ∼750 to ∼635 Myr ago, indicating unusually high dissolved phosphate concentrations in the aftermath of widespread, low-latitude ‘snowball Earth’ glaciations. An enhanced postglacial phosphate flux would have caused high rates of primary productivity and organic carbon burial and a transition to more oxidizing conditions in the ocean and atmosphere. The snowball Earth glaciations and Neoproterozoic oxidation are both suggested as triggers for the evolution and radiation of metazoans6,7. We propose that these two factors are intimately linked; a glacially induced nutrient surplus could have led to an increase in atmospheric oxygen, paving the way for the rise of metazoan life.

Growth-limiting Intracellular Metabolites in Yeast Growing under Diverse Nutrient Limitations

Abstract: Microbes tailor their growth rate to nutrient availability. Here, we measured, using liquid chromatography-mass spectrometry, >100 intracellular metabolites in steady-state cultures of Saccharomyces cerevisiae growing at five different rates and in each of five different limiting nutrients. In contrast to gene transcripts, where approximately 25% correlated with growth rate irrespective of the nature of the limiting nutrient, metabolite concentrations were highly sensitive to the limiting nutrient's identity. Nitrogen (ammonium) and carbon (glucose) limitation were characterized by low intracellular amino acid and high nucleotide levels, whereas phosphorus (phosphate) limitation resulted in the converse. Low adenylate energy charge was found selectively in phosphorus limitation, suggesting the energy charge may actually measure phosphorus availability. Particularly strong concentration responses occurred in metabolites closely linked to the limiting nutrient, e.g., glutamine in nitrogen limitation, ATP in phosphorus limitation, and pyruvate in carbon limitation. A simple but physically realistic model involving the availability of these metabolites was adequate to account for cellular growth rate. The complete data can be accessed at the interactive website http://growthrate.princeton.edu/metabolome.

Strategies for improving phosphorus acquisition efficiency of crop plants [Approved article]

Abstract: Abstract In many low input agricultural systems, phosphorus (P) is one of the most limiting mineral nutrients for plant production. Although applying P fertilizer, if available, is the most performing practice, this should be accompanied by other measures. The use of genetically enhanced plants with improved P acquisition efficiency may represent a sustainable solution to increase crop yields in these systems. This review is intended to provide a summary on adaptation mechanisms of crop plants facing P deficiency as the starting point to develop a research approach for improving P acquisition efficiency. P acquisition efficiency in this review refers to external P efficiency. The suggested research approach includes three strategies: molecular assisted plant breeding, deployment of transgenic plants and the use of agricultural practices. The natural source for improving P nutrition of plants is the existing large genetic variation for plant traits that are associated with P acquisition efficiency and will therefore be emphasized in this review.

Sargasso Sea phosphorus biogeochemistry: an important role for dissolved organic phosphorus (DOP)

Abstract: . Inorganic phosphorus (SRP) concentrations in the subtropical North Atlantic are some of the lowest in the global ocean and have been hypothesized to constrain primary production. Based upon data from several transect cruises in this region, it has been hypothesized that dissolved organic phosphorus (DOP) supports a significant fraction of primary production in the subtropical North Atlantic. In this study, a time-series of phosphorus biogeochemistry is presented for the Bermuda Atlantic Time-series Study site, including rates of phosphorus export. Most parameters have a seasonal pattern, although year-over-year variability in the seasonal pattern is substantial, likely due to differences in external forcing. Suspended particulate phosphorus exhibits a seasonal maximum during the spring bloom, despite the absence of a seasonal peak in SRP. However, DOP concentrations are at an annual maximum prior to the winter/spring bloom and decline over the course of the spring bloom while whole community alkaline phosphatase activities are highest. As a result of DOP bioavailability, the growth of particles during the spring bloom occurs in Redfield proportions, though particles exported from the euphotic zone show rapid and significant remineralization of phosphorus within the first 50 m below the euphotic zone. Based upon DOP data from transect cruises in this region, the southward cross gyral flux of DOP is estimated to support ~25% of annual primary production and ~100% of phosphorus export. These estimates are consistent with other research in the subtropical North Atlantic and reinforce the hypothesis that while the subtropics may be phosphorus stressed (a physiological response to low inorganic phosphorus), utilization of the DOP pool allows production and accumulation of microbial biomass at Redfield proportions.

Association of dietary phosphorus intake and phosphorus to protein ratio with mortality in hemodialysis patients.

Abstract: Background and objectives: Epidemiologic studies show an association between higher predialysis serum phosphorus and increased death risk in maintenance hemodialysis (MHD) patients. The hypothesis that higher dietary phosphorus intake and higher phosphorus content per gram of dietary protein intake are each associated with increased mortality in MHD patients was examined. Design, setting, participants, & measurements: Food frequency questionnaires were used to conduct a cohort study to examine the survival predictability of dietary phosphorus and the ratio of phosphorus to protein intake. At the start of the cohort, Cox proportional hazard regression was used in 224 MHD patients, who were followed for up to 5 years (2001 to 2006). Results: Both higher dietary phosphorus intake and a higher dietary phosphorus to protein ratio were associated with significantly increased death hazard ratios (HR) in the unadjusted models and after incremental adjustments for case-mix, diet, serum phosphorus, malnutrition-inflammation complex syndrome, and inflammatory markers. The HR of the highest (compared with lowest) dietary phosphorus intake tertile in the fully adjusted model was 2.37. Across categories of dietary phosphorus to protein ratios of <12, 12 to <14, 14 to <16, and ≥16 mg/g, death HRs were 1.13, 1.00 (reference value), 1.80, and 1.99, respectively. Cubic spline models of the survival analyses showed similar incremental associations. Conclusions: Higher dietary phosphorus intake and higher dietary phosphorus to protein ratios are each associated with increased death risk in MHD patients, even after adjustments for serum phosphorus, phosphate binders and their types, and dietary protein, energy, and potassium intakes.

Humic (Organic Matter)-Al(Fe)-Phosphate Complexes: An Underestimated Phosphate Form in Soils and Source of Plant-Available Phosphate

Abstract: The chemical interaction between soil organic matter and the orthophosphate anion (phosphate [P]) is important for reactions of P at the soil solid phase, in soil solution, and in natural waters. Humic substances account for an important or dominant part of soil organic matter and of dissolv

Phosphate Removal by Anion Binding on Functionalized Nanoporous Sorbents

Abstract: Phosphate was captured from aqueous solutions by cationic metal-EDA complexes anchored inside mesoporous silica MCM-41 supports (Cu(II)-EDA-SAMMS and Fe(III)-EDA-SAMMS). Fe-EDA-SAMMS was more effective at capturing phosphate than the Cu-EDA-SAMMS and was further studied for matrix effects (e.g., pH, ionic strength, and competing anions) and sorption performance (e.g., capacity and rate). The adsorption of phosphate was highly pH dependent; it increased with increasing pH from 1.0 to 6.5, and decreased above pH 6.5. The adsorption was affected by high ionic strength (0.1 M of NaCl). In the presence of 1000-fold molar excess of chloride and nitrate anions, phosphate removal by Fe-EDA-SAMMS was not affected. Slight, moderate and large impacts were seen with bicarbonate, sulfate and citrate anions, respectively. The phosphate adsorption data on Fe-EDA-SAMMS agreed well with the Langmuir model with the estimated maximum capacity of 43.3 mg/g. The material displayed rapid sorption rate (99% of phosphate removal within 1 min) and lowering the phosphate content to ~ 10 µg/L of phosphorus, which is lower than the EPA’s established freshwater contaminant level for phosphorous (20 µg/L).

A Berzelius Reagent, Phosphorus Decasulfide (P4S10), in Organic Syntheses

Abstract: 2.3. Amides and Lactams 3435 2.4. Imides 3448 2.5. Thiophenes 3451 2.6. Thiazolines, Thiazoles, and Thiazines 3454 2.7. Dithiazoles 3456 2.8. Thiadiazoles 3456 2.9. Imidazolines and Pyrimidines 3456 2.10. Alcohols 3458 2.11. PdO to PdS 3461 2.12. Reduction 3462 2.13. Nucleotides, Purines, and Pyrimidines 3463 2.14. Miscellaneous 3467 2.15. P4S10 vs Lawesson’s Reagent (LR) 3473 3. Conclusion 3473 4. Acknowledgments 3473 5. References 3473

Soil organic phosphorus dynamics following perturbation of litter cycling in a tropical moist forest

Abstract: The productivity of tropical lowland moist forests is often considered to be limited by the availability of phosphorus Organic phosphorus is often abundant in tropical soils, but its role in forest nutrition is largely unknown We addressed this by using a large-scale litter manipulation experiment to investigate the stability of soil organic phosphorus in a tropical lowland forest in Central Panama Three years of litter removal reduced the organic phosphorus concentration in the surface 2 cm of mineral soil by 23%, as determined by NaOH-EDTA extraction and 31P-NMR spectroscopy; this included decreases in phosphate monoesters (20%) and DNA (30%) Three years of litter addition (equivalent to adding 6 kg P ha-1 per year) increased soil organic phosphorus by 16%, which included a 31% increase in DNA We did not detect higher-order inositol phosphates, despite their abundance in mineral soils of temperate ecosystems Our observed turnover rate suggests that even the 0-2-cm layer of the mineral soil contributes a fifth of the total phosphorus needed to sustain above-ground growth in this forest Soil organic phosphorus is thus likely to make a more important contribution to the nutrition of semi-evergreen forest plants than has hitherto been acknowledged

The Story of Phosphorus : Sustainability implications of global phosphorus scarcity for food security

Abstract: The story of phosphorus began with the search for the philosopher’s stone, and centuries later the critical role of phosphorus in soil fertility and crop growth was highlighted. Eventually, phospho ...

Organic acid production and plant growth promotion as a function of phosphate solubilization by Acinetobacter rhizosphaerae strain BIHB 723 isolated from the cold deserts of the trans-Himalayas.

Abstract: An efficient phosphate-solubilizing plant growth-promoting Acinetobacter rhizosphaerae strain BIHB 723 exhibited significantly higher solubilization of tricalcium phosphate (TCP) than Udaipur rock phosphate (URP), Mussoorie rock phosphate (MRP) and North Carolina rock phosphate (NCRP). Qualitative and quantitative differences were discerned in the gluconic, oxalic, 2-keto gluconic, lactic, malic and formic acids during the solubilization of various inorganic phosphates by the strain. Gluconic acid was the main organic acid produced during phosphate solubilization. Formic acid production was restricted to TCP solubilization and oxalic acid production to the solubilization of MRP, URP and NCRP. A significant increase in plant height, shoot fresh weight, shoot dry weight, root length, root dry weight, and root, shoot and soil phosphorus (P) contents was recorded with the inoculated treatments over the uninoculated NP(0)K or NP(TCP)K treatments. Plant growth promotion as a function of phosphate solubilization suggested that the use of bacterial strain would be a beneficial addition to the agriculture practices in TCP-rich soils in reducing the application of phosphatic fertilizers.

Magnitude of oceanic nitrogen fixation influenced by the nutrient uptake ratio of phytoplankton

Abstract: The ratio of nitrogen to phosphorus in phytoplankton varies greatly with taxa and growth conditions. An ecosystem model suggests that the relative abundance of fast- and slow-growing phytoplankton controls the amount of new nitrogen added to the ocean. The elemental stoichiometry of sea water and particulate organic matter is remarkably similar. This observation led Redfield to hypothesize that the oceanic ratio of nitrate to phosphate is controlled by the remineralization of phytoplankton biomass1. The Redfield ratio is used universally to quantitatively link the marine nitrogen and phosphorus cycles in numerous biogeochemical applications2,3,4. Yet, empirical and theoretical studies show that the ratio of nitrogen to phosphorus in phytoplankton varies greatly with taxa5,6 and growth conditions7,8,9. Here we present a dynamic five-box ecosystem model showing that non-Redfield utilization of dissolved nitrogen and phosphorus by non-nitrogen-fixing phytoplankton controls the magnitude and distribution of nitrogen fixation. In our simulations, systems dominated by rapidly growing phytoplankton with low nitrogen to phosphorus uptake ratios reduce the phosphorus available for nitrogen fixation. In contrast, in systems dominated by slow-growing phytoplankton with high nitrogen to phosphorus uptake ratios nitrogen deficits are enhanced, and nitrogen fixation is promoted. We show that estimates of nitrogen fixation are up to fourfold too high when non-Redfield uptake stoichiometries are ignored. We suggest that the relative abundance of fast- and slow-growing phytoplankton controls the amount of new nitrogen added to the ocean.

Phosphorus Solubilization and Potential Transfer to Surface Waters from the Soil Microbial Biomass Following Drying–Rewetting and Freezing–Thawing

Abstract: Drying–rewetting and freezing–thawing are two of the most common forms of abiotic perturbations experienced by soils, and can result in the solubilization of phosphorus (P). There is increasing interest in one particular component of soil P that may be especially susceptible to such stresses: the soil microbial biomass. We examine the evidence for the soil microbial biomass acting as a significant source of P in soils and surface waters by studying the literature on the processes responsible for its solubilization and transfer, resulting from abiotic perturbations. These perturbations have been shown to kill up to circa 70% of the total microbial biomass in some soils, and in some cases nearly all the additional P solubilized has been attributed to the microbial biomass. The degree to which the soil microbial biomass is affected by abiotic perturbations is highly dependent upon many variables, not the least degree, duration, and temporal patterns of stress, as well as the soil type. It is hypothesized that while abiotic perturbations can solubilize large quantities of P from the soil microbial biomass in some soils, only a small proportion is likely to find its way from the soil to surface waters. This is not to say that this small proportion is not significant with regard to surface water quality and nutrient loss from the soil, and may become more prevalent under future climatic change. We conclude that it is likely that only extreme conditions will elicit large responses with regard to the solubilization and transfer of phosphorus to surface waters.

Phosphorus-modified ZSM-5 for conversion of ethanol to propylene

Abstract: In this work, phosphorus-modified ZSM-5 zeolites were used to transform ethanol to propylene. The selectivity of propylene formation depended strongly on the phosphorus content in the zeolites; the highest propylene yield (32%) was observed over H-ZSM-5(80) modified with phosphorus at a P/Al molar ratio of 0.5. The enhancement of propylene selectivity with increasing phosphorus content was attributed to reduction of strong acid sites on the H-ZSM-5. Modification of the zeolite with phosphorous also improved the material's catalytic stability.

Common Genetic Variants Associate with Serum Phosphorus Concentration

Abstract: Phosphorus is an essential mineral that maintains cellular energy and mineralizes the skeleton. Because complex actions of ion transporters and regulatory hormones regulate serum phosphorus concentrations, genetic variation may determine interindividual variation in phosphorus metabolism. Here, we report a comprehensive genome-wide association study of serum phosphorus concentration. We evaluated 16,264 participants of European ancestry from the Cardiovascular Heath Study, Atherosclerosis Risk in Communities Study, Framingham Offspring Study, and the Rotterdam Study. We excluded participants with an estimated GFR 45 ml/min per 1.73 m 2 to focus on phosphorus metabolism under normal conditions. We imputed genotypes to approximately 2.5 million single-nucleotide polymorphisms in the HapMap and combined study-specific findings using meta-analysis. We tested top polymorphisms from discovery cohorts in a 5444-person replication sample. Polymorphisms in seven loci with minor allele frequencies 0.08 to 0.49 associate with serum phosphorus concentration (P 3.5 10 16 to 3.6 10 7 ). Three loci were near genes encoding the kidney-specific type IIa sodium phosphate co-transporter (SLC34A1), the calcium-sensing receptor (CASR), and fibroblast growth factor 23 (FGF23), proteins that contribute to phosphorus metabolism. We also identified genes encoding phosphatases, kinases, and phosphodiesterases that have yetundetermined roles in phosphorus homeostasis. In the replication sample, five of seven top polymorphisms associate with serum phosphorous concentrations (P 0.05 for each). In conclusion, common genetic variants associate with serum phosphorus in the general population. Further study of the loci identified in this study may help elucidate mechanisms of phosphorus regulation.