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Benjamin L. Turner - One of the best experts on this subject based on the ideXlab platform.

  • Determination of neo- and d-chiro-Inositol Hexakisphosphate in Soils by Solution 31P NMR Spectroscopy
    2015
    Co-Authors: Benjamin L. Turner, Alexander W Cheesman, Yasmin H Godage, Andrew M. Riley, Barry V L Potter
    Abstract:

    The inositol phosphates are an abundant but poorly understood group of Organic Phosphorus compounds found widely in the environment. Four stereoisomers of inositol hexakisphosphate (IP6) occur, although for three of these (scyllo, neo, and d-chiro) the origins, dynamics, and biological function remain unknown, due in large part to analytical limitations in their measurement in environmental samples. We synthesized authentic neo- and d-chiro-IP6 and used them to identify signals from these compounds in three soils from the Falkland Islands. Both compounds resisted hypobromite oxidation and gave quantifiable 31P NMR signals at δ = 6.67 ppm (equatorial phosphate groups of the 4-equatorial/2-axial conformer of neo-IP6) and δ = 6.48 ppm (equatorial phosphate groups of the 2-equatorial/4-axial conformer of d-chiro-IP6) in soil extracts. Inositol hexakisphosphate accounted for 46–54% of the soil Organic Phosphorus, of which the four stereoisomers constituted, on average, 55.9% (myo), 32.8% (scyllo), 6.1% (neo), and 5.2% (d-chiro). Reappraisal of the literature based on the new signal assignments revealed that neo- and d-chiro-IP6 occur widely in both terrestrial and aquatic ecosystems. These results confirm that the inositol phosphates can constitute a considerable fraction of the Organic Phosphorus in soils and reveal the prevalence of neo- and d-chiro-IP6 in the environment. The hypobromite oxidation and solution 31P NMR spectroscopy procedure allows the simultaneous quantification of all four IP6 stereoisomers in environmental samples and provides a platform for research into the origins and ecological significance of these enigmatic compounds

  • using Organic Phosphorus to sustain pasture productivity a perspective
    Geoderma, 2014
    Co-Authors: David Nash, Benjamin L. Turner, Leo M. Condron, P M Haygarth, R W Mcdowell, Alan Richardson, Mark Watkins, Michael W Heaven
    Abstract:

    Abstract Organic Phosphorus (P) in grazed pastures/grasslands could sustain production systems that historically relied on inOrganic P fertiliser. Interactions between inOrganic P, plants and soils have been studied extensively. However, less is known about the transformation of Organic P to inOrganic orthophosphate. This paper investigates what is known about Organic P in pasture/grassland soils used for agriculture, as well as the research needed to utilise Organic P for sustainable plant production. Organic P comprises > 50% of total soil P in agricultural systems depending on location, soil type and land use. Organic P hydrolysis and release of orthophosphate by phosphatase enzymatic activity is affected by a range of factors including: (a) the chemical nature of the Organic P and its ability to interact with the soil matrix; (b) microorganisms that facilitate mineralisation; (c) soil mineralogy; (d) soil water electrolytes; and (e) soil physicochemical properties. Current biogeochemical knowledge of Organic P processing in soil limits our ability to develop management strategies that promote the use of Organic P in plant production. Information is particularly needed on the types and sources of Organic P in grassland systems and the factors affecting the activity of enzymes that mineralise Organic P. Integrated approaches analysing the soil matrix, soil water and soil biology are suggested to address this knowledge gap.

  • determination of neo and d chiro inositol hexakisphosphate in soils by solution 31p nmr spectroscopy
    Environmental Science & Technology, 2012
    Co-Authors: Benjamin L. Turner, Andrew M. Riley, Alexander W Cheesman, Yasmin H Godage, Barry V L Potter
    Abstract:

    The inositol phosphates are an abundant but poorly understood group of Organic Phosphorus compounds found widely in the environment. Four stereoisomers of inositol hexakisphosphate (IP6) occur, although for three of these (scyllo, neo, and d-chiro) the origins, dynamics, and biological function remain unknown, due in large part to analytical limitations in their measurement in environmental samples. We synthesized authentic neo- and d-chiro-IP6 and used them to identify signals from these compounds in three soils from the Falkland Islands. Both compounds resisted hypobromite oxidation and gave quantifiable 31P NMR signals at δ = 6.67 ppm (equatorial phosphate groups of the 4-equatorial/2-axial conformer of neo-IP6) and δ = 6.48 ppm (equatorial phosphate groups of the 2-equatorial/4-axial conformer of d-chiro-IP6) in soil extracts. Inositol hexakisphosphate accounted for 46–54% of the soil Organic Phosphorus, of which the four stereoisomers constituted, on average, 55.9% (myo), 32.8% (scyllo), 6.1% (neo), ...

  • linking Phosphorus sequestration to carbon humification in wetland soils by 31p and 13c nmr spectroscopy
    Environmental Science & Technology, 2012
    Co-Authors: Rasha Hamdan, Benjamin L. Turner, Alexander W Cheesman, Hasan M Elrifai, Ramesh K Reddy, William T Cooper
    Abstract:

    Phosphorus sequestration in wetland soils is a prerequisite for long-term maintenance of water quality in downstream aquatic systems, but can be compromised if Phosphorus is released following changes in nutrient status or hydrological regimen. The association of Phosphorus with relatively refractory natural Organic matter (e.g., humic substances) might protect soil Phosphorus from such changes. Here we used hydrofluoric acid (HF) pretreatment to remove Phosphorus associated with metals or anionic sorption sites, allowing us to isolate a pool of Phosphorus associated with the soil Organic fraction. Solution 31P and solid state 13C NMR spectra for wetland soils were acquired before and after hydrofluoric acid pretreatment to assess quantitatively and qualitatively the changes in Phosphorus and carbon functional groups. Organic Phosphorus was largely unaffected by HF treatment in soils dominated by refractory alkyl and aromatic carbon groups, indicating association of Organic Phosphorus with stable, humifie...

  • soil Organic Phosphorus in lowland tropical rain forests
    Biogeochemistry, 2011
    Co-Authors: Benjamin L. Turner, Bettina M J Engelbrecht
    Abstract:

    Phosphorus is widely considered to constrain primary productivity in tropical rain forests, yet the chemistry of soil Organic Phosphorus in such ecosystems remains poorly understood. We assessed the composition of soil Organic Phosphorus in 19 contrasting soils under lowland tropical forest in the Republic of Panama using NaOH–EDTA extraction and solution 31P nuclear magnetic resonance spectroscopy. The soils spanned a strong rainfall gradient (1730–3404 mm y−1) and contained a wide range of chemical properties (pH 3.3–7.0; total carbon 2.8–10.4%; total Phosphorus 74–1650 mg P kg−1). Soil Organic Phosphorus concentrations ranged between 22 and 494 mg P kg−1 and were correlated positively with total soil Phosphorus, pH, and total carbon, but not with annual rainfall. Organic Phosphorus constituted 26 ± 1% (mean ± STD error, n = 19) of the total Phosphorus, suggesting that this represents a broad emergent property of tropical forest soils. Organic Phosphorus occurred mainly as phosphate monoesters (68–96% of total Organic Phosphorus) with smaller concentrations of phosphate diesters in the form of DNA (4–32% of total Organic Phosphorus). Phosphonates, which contain a direct carbon–Phosphorus bond, were detected in only two soils (3% of the Organic Phosphorus), while pyrophosphate, an inOrganic polyphosphate with a chain length of two, was detected in all soils at concentrations up to 13 mg P kg−1 (3–13% of extracted inOrganic Phosphorus). Phosphate monoesters were a greater proportion of the total Organic Phosphorus in neutral soils with high concentrations of Phosphorus and Organic matter, whereas the proportion of phosphate diesters was greater in very acidic soils low in Phosphorus and Organic matter. Most soils did not contain detectable concentrations of either myo- or scyllo-inositol hexakisphosphate, which is in marked contrast to many temperate mineral soils that contain abundant inositol phosphates. We conclude that soil properties exert a strong control on the amounts and forms of soil Organic Phosphorus in tropical rain forests, but that the proportion of the total Phosphorus in Organic forms is relatively insensitive to variation in climate and soil properties. Further work is now required to assess the contribution of soil Organic Phosphorus to the nutrition and diversity of plants in these species-rich ecosystems.

Leo M. Condron - One of the best experts on this subject based on the ideXlab platform.

  • impact of land use and nutrient addition on phosphatase activities and their relationships with Organic Phosphorus turnover in semi arid grassland soils
    Biology and Fertility of Soils, 2016
    Co-Authors: Jihui Tian, Leo M. Condron, Kai Wei, Zhenhua Chen, Lijun Chen
    Abstract:

    Information on the relationships between phosphatase activities and Organic Phosphorus (P) turnover is fundamental to understanding soil P dynamics but remains poorly understood. An 8-year field study was conducted in a steppe and an abandoned cropland under semi-arid grasslands to explore the effects of nitrogen (N) and P additions on P composition in soil as determined by 31P nuclear magnetic resonance (NMR) and associated phosphatase activities. Results showed that the phosphate monoester content, soil acid phosphomonoesterase, alkaline phosphomonoesterase, and phosphodiesterase activities were higher in the steppe than in the abandoned cropland soil. Nitrogen addition significantly suppressed phosphatase activities. Phosphorus addition significantly increased acid phosphomonoesterase, alkaline phosphomonoesterase, and phosphodiesterase activities in the steppe but significantly decreased them in the abandoned cropland. Structural equation modeling revealed that both phosphodiesterase and alkaline phosphomonoesterase activities showed significant negative effects on diesters and monoesters in the steppe, but there were no significant effects of phosphatase activities on Organic P composition in the abandoned cropland. Our findings highlight the variation of dominant mechanisms involved in Organic P turnover with land use change. Phosphorus deficiency in the steppe appeared to promote the production of phosphatases and the subsequent biochemical mineralization of Organic P. While in the abandoned cropland, previous cultivation resulted in a proportionally greater loss of soil Organic carbon than that of Organic P, indicating that Organic P was mineralized as a result of biological mineralization of Organic matter.

  • using Organic Phosphorus to sustain pasture productivity a perspective
    Geoderma, 2014
    Co-Authors: David Nash, Benjamin L. Turner, Leo M. Condron, P M Haygarth, R W Mcdowell, Alan Richardson, Mark Watkins, Michael W Heaven
    Abstract:

    Abstract Organic Phosphorus (P) in grazed pastures/grasslands could sustain production systems that historically relied on inOrganic P fertiliser. Interactions between inOrganic P, plants and soils have been studied extensively. However, less is known about the transformation of Organic P to inOrganic orthophosphate. This paper investigates what is known about Organic P in pasture/grassland soils used for agriculture, as well as the research needed to utilise Organic P for sustainable plant production. Organic P comprises > 50% of total soil P in agricultural systems depending on location, soil type and land use. Organic P hydrolysis and release of orthophosphate by phosphatase enzymatic activity is affected by a range of factors including: (a) the chemical nature of the Organic P and its ability to interact with the soil matrix; (b) microorganisms that facilitate mineralisation; (c) soil mineralogy; (d) soil water electrolytes; and (e) soil physicochemical properties. Current biogeochemical knowledge of Organic P processing in soil limits our ability to develop management strategies that promote the use of Organic P in plant production. Information is particularly needed on the types and sources of Organic P in grassland systems and the factors affecting the activity of enzymes that mineralise Organic P. Integrated approaches analysing the soil matrix, soil water and soil biology are suggested to address this knowledge gap.

  • extraction of soil Organic Phosphorus
    Talanta, 2005
    Co-Authors: Benjamin L. Turner, Leo M. Condron, Barbara J Cademenun, Susan Newman
    Abstract:

    Organic Phosphorus is an important component of soil biogeochemical cycles, but must be extracted from soil prior to analysis. Here we critically review the extraction of soil Organic Phosphorus, including procedures for quantification, speciation, and assessment of biological availability. Quantitative extraction conventionally requires strong acids and bases, which inevitably alter chemical structure. However, a single-step procedure involving sodium hydroxide and EDTA (ethylenediaminetetraacetate) is suitable for most soils and facilitates subsequent speciation by nuclear magnetic resonance spectroscopy. Analysis of extracts by molybdate colorimetry is a potential source of error in all procedures, because Organic Phosphorus is overestimated in the presence of inOrganic polyphosphates or complexes between inOrganic phosphate and humic substances. Sequential extraction schemes fractionate Organic Phosphorus based on chemical solubility, but the link to potential bioavailability is misleading. Research should be directed urgently towards establishing extractable pools of soil Organic Phosphorus with ecological relevance.

  • Quantification of myo-inositol hexakisphosphate in alkaline soil extracts by solution 31P NMR spectroscopy and spectral deconvolution
    Soil Science, 2003
    Co-Authors: Benjamin L. Turner, N. Mahieu, Leo M. Condron
    Abstract:

    Inositol phosphates are the dominant class of Organic Phosphorus (P) compounds in most soils, but are poorly understood because they are not easily identified in soil extracts. This study reports a relatively simple technique using solution 31P NMR spectroscopy and spectral deconvolution for the qua

Chaosheng Zhang - One of the best experts on this subject based on the ideXlab platform.

  • speciation of Organic Phosphorus in a sediment profile of lake taihu ii molecular species and their depth attenuation
    Journal of Environmental Sciences-china, 2013
    Co-Authors: Shiming Ding, Xiuling Bai, Chengxin Fan, Shuchun Yao, Chaosheng Zhang
    Abstract:

    Abstract The understanding of Organic Phosphorus (P) dynamics in sediments requires information on their species at the molecular level, but such information in sediment profiles is scarce. A sediment profile was selected from a large eutrophic lake, Lake Taihu (China), and Organic P species in the sediments were detected using solution Phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) following extraction of the sediments with a mixture of 0.25 mol/L NaOH and 50 mmol/L EDTA (NaOH-EDTA) solution. The results showed that P in the NaOH-EDTA extracts was mainly composed of orthophosphate, orthophosphate monoesters, phospholipids, DNA, and pyrophosphate. Concentrations of the major Organic P compound groups and pyrophosphate showed a decreasing trend with the increase of depth. Their half-life times varied from 3 to 27 years, following the order of orthophosphate monoesters > phospholipids ≥ DNA > pyrophosphate. Principal component analysis revealed that the detected Organic P species had binding phases similar to those of humic acid-associated Organic P (NaOH-NRPHA), a labile Organic P pool that tends to transform to recalcitrant Organic P pools as the early diagenetic processes proceed. This demonstrated that the depth attenuation of the Organic P species could be partly attributed to their increasing immobilization by the sediment solids, while their degradation rates should be significantly lower than what were suggested in previous studies.

  • speciation of Organic Phosphorus in a sediment profile of lake taihu i chemical forms and their transformation
    Journal of Environmental Sciences-china, 2013
    Co-Authors: Shiming Ding, Xiuling Bai, Chengxin Fan, Chaosheng Zhang
    Abstract:

    Abstract Organic Phosphorus (nonreactive P, NRP) is a major component of P in sediments, but information about its chemical forms and dynamic transformation is limited. The chemical forms and dynamic behaviors of NRP in a sediment profile from Lake Taihu, a freshwater and eutrophic lake in China, were investigated. Five forms of NRP in the sediments were extracted based on a chemical fractionation technique, including easily labile NRP (NaHCO 3 -NRP), reactive metal oxide-bound NRP (HC1-NRP), humic acid-associated NRP (NaOH-NRP HA ), fulvic acid-associated NRP (NaOH-NRP FA ) and residual NRP (Res-TP). There were notable transformations with increasing sediment depth from the labile NaHCO 3 -NRP and NaOH-NRP pools to the recalcitrant HC1-NRP and Res-TP pools, which caused the NRP to become increasingly recalcitrant as the early diagenetic processes proceeded. Further analyses showed that the relative changes in contents of Organic matter and reactive Fe oxides in the sediment profile triggered a competition for binding NRP fractions and led to the transformation of NRP. The results highlighted the importance of abiotic processes in regulating the diagenesis of Organic P and its stability in sediments.

  • characterization and optimization of the preparation procedure for solution p 31 nmr analysis of Organic Phosphorus in sediments
    Journal of Soils and Sediments, 2012
    Co-Authors: Di Xu, Shiming Ding, Bin Li, Xiang He, Chaosheng Zhang
    Abstract:

    Purpose The single-step sodium hydroxide–ethylenediaminetetraacetic acid (NaOH–EDTA) extraction is currently the most common preparation technique for the measurement of Organic Phosphorus (P) composition in sediments using solution 31P nuclear magnetic resonance (NMR). In this study, detailed investigations were conducted to evaluate the performance of this technique, with an objective of finding an optimal procedure for the measurement of sediment Organic P.

Shiming Ding - One of the best experts on this subject based on the ideXlab platform.

  • speciation of Organic Phosphorus in a sediment profile of lake taihu ii molecular species and their depth attenuation
    Journal of Environmental Sciences-china, 2013
    Co-Authors: Shiming Ding, Xiuling Bai, Chengxin Fan, Shuchun Yao, Chaosheng Zhang
    Abstract:

    Abstract The understanding of Organic Phosphorus (P) dynamics in sediments requires information on their species at the molecular level, but such information in sediment profiles is scarce. A sediment profile was selected from a large eutrophic lake, Lake Taihu (China), and Organic P species in the sediments were detected using solution Phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) following extraction of the sediments with a mixture of 0.25 mol/L NaOH and 50 mmol/L EDTA (NaOH-EDTA) solution. The results showed that P in the NaOH-EDTA extracts was mainly composed of orthophosphate, orthophosphate monoesters, phospholipids, DNA, and pyrophosphate. Concentrations of the major Organic P compound groups and pyrophosphate showed a decreasing trend with the increase of depth. Their half-life times varied from 3 to 27 years, following the order of orthophosphate monoesters > phospholipids ≥ DNA > pyrophosphate. Principal component analysis revealed that the detected Organic P species had binding phases similar to those of humic acid-associated Organic P (NaOH-NRPHA), a labile Organic P pool that tends to transform to recalcitrant Organic P pools as the early diagenetic processes proceed. This demonstrated that the depth attenuation of the Organic P species could be partly attributed to their increasing immobilization by the sediment solids, while their degradation rates should be significantly lower than what were suggested in previous studies.

  • speciation of Organic Phosphorus in a sediment profile of lake taihu i chemical forms and their transformation
    Journal of Environmental Sciences-china, 2013
    Co-Authors: Shiming Ding, Xiuling Bai, Chengxin Fan, Chaosheng Zhang
    Abstract:

    Abstract Organic Phosphorus (nonreactive P, NRP) is a major component of P in sediments, but information about its chemical forms and dynamic transformation is limited. The chemical forms and dynamic behaviors of NRP in a sediment profile from Lake Taihu, a freshwater and eutrophic lake in China, were investigated. Five forms of NRP in the sediments were extracted based on a chemical fractionation technique, including easily labile NRP (NaHCO 3 -NRP), reactive metal oxide-bound NRP (HC1-NRP), humic acid-associated NRP (NaOH-NRP HA ), fulvic acid-associated NRP (NaOH-NRP FA ) and residual NRP (Res-TP). There were notable transformations with increasing sediment depth from the labile NaHCO 3 -NRP and NaOH-NRP pools to the recalcitrant HC1-NRP and Res-TP pools, which caused the NRP to become increasingly recalcitrant as the early diagenetic processes proceeded. Further analyses showed that the relative changes in contents of Organic matter and reactive Fe oxides in the sediment profile triggered a competition for binding NRP fractions and led to the transformation of NRP. The results highlighted the importance of abiotic processes in regulating the diagenesis of Organic P and its stability in sediments.

  • characterization and optimization of the preparation procedure for solution p 31 nmr analysis of Organic Phosphorus in sediments
    Journal of Soils and Sediments, 2012
    Co-Authors: Di Xu, Shiming Ding, Bin Li, Xiang He, Chaosheng Zhang
    Abstract:

    Purpose The single-step sodium hydroxide–ethylenediaminetetraacetic acid (NaOH–EDTA) extraction is currently the most common preparation technique for the measurement of Organic Phosphorus (P) composition in sediments using solution 31P nuclear magnetic resonance (NMR). In this study, detailed investigations were conducted to evaluate the performance of this technique, with an objective of finding an optimal procedure for the measurement of sediment Organic P.

  • Organic Phosphorus species in surface sediments of a large shallow eutrophic lake lake taihu china
    Environmental Pollution, 2009
    Co-Authors: Xiuling Bai, Shiming Ding, Chengxin Fan, Tao Liu, Dan Shi, Lu Zhang
    Abstract:

    Abstract Organic Phosphorus (P) fractions in surface sediments from a large shallow, eutrophic Lake Taihu, China, were extracted with 0.1 M NaOH after pre-treatment of the sediments with a solution composed of 0.1 M EDTA and 2% (w/v) Na 2 S 2 O 4 . Composition of Organic P in the extracts was then characterized by 31 P nuclear magnetic resonance spectroscopy ( 31 P NMR). Several P species, including phosphonates, orthophosphate, orthophosphate monoesters, phospholipids, DNA, pyrophosphate and polyphosphate, were detected in the NaOH extracts. The proportion of extracted Organic P to total P in sediments was negatively correlated with total P in the water column, as were the proportions for orthophosphate monoesters and DNA. This implies that the majority of Organic P in surface sediments is likely stabilized in some way, and does not directly contribute to the internal loading of P from sediments.

Andrea G Vincent - One of the best experts on this subject based on the ideXlab platform.