umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Analysis and speciation of organic phosphorus in environmental matrices: Development of methods to improve 31P NMR analysis
Umeå University, Faculty of Science and Technology, Department of Chemistry. (Gerhard Gröbner)ORCID iD: 0000-0001-9395-5030
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Phosphorus (P) is an essential element for life on our planet. It is central in numerous biochemical processes in terrestrial and aqueous ecosystems including food production; and it is the primary growth-limiting nutrient in some of the world’s biomes. The main source of P for use as agricultural fertilizer is mining of non-renewable mineral phosphate. In terrestrial ecosystems the main source is soil P, where the largest fraction is organic P, composed of many species with widely differing properties. This fraction controls the utilization of P by plants and microorganisms and influences ecosystem development and productivity. However, there is only scarce knowledge about the molecular composition of the organic P pool, about the processes controlling its bioavailability, and about its changes as soils develop. Therefore, the aim of this thesis was to develop robust solution- and solid-state 31P nuclear magnetic resonance spectroscopy (NMR) methods to provide molecular information about speciation of the organic P pool, and to study its dynamics in boreal and tropical soils. By studying humus soils of a groundwater recharge/discharge productivity gradient in a Fennoscandian boreal forest by solution- and solid-state NMR, it was found that P speciation changed with productivity. In particular, the level of orthophosphate diesters decreased with increasing productivity while mono-esters such as inositol phosphates increased. Because the use of solution NMR on conventional NaOH/EDTA extracts of soils was limited due to severe line broadening caused by the presence of paramagnetic metal ions, a new extraction method was developed and validated. Based on the removal of these paramagnetic impurities by sulfide precipitation, a dramatic decrease in NMR linewidths was obtained, allowing for the first time to apply modern multi-dimensional solution NMR techniques to soil extracts. Identification of individual soil P-species, and tracking changes in the organic P pools during soil development provided information for connecting P-speciation to bioavailability and ecosystem properties. Using this NMR approach we studied the transformation of organic P in humus soils along a chronosequence (7800 years) in Northern Sweden. While total P varied little, the composition of the soil P pool changed particularly among young sites, where also the largest shift in the composition of the plant community and of soil microorganisms was observed. Very old soils, such as found Africa, are thought to strongly adsorb P, limiting plant productivity. I used NMR to study the effect of scattered agroforestry trees on P speciation in two semi-arid tropical woodlands with different soil mineralogy (Burkina Faso). While the total P concentration was low, under the tree canopies higher amounts of P and higher diversity of P-species were found, presumably reflecting higher microbial activity.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet , 2014. , 58 p.
Keyword [en]
Phosphorus, soil, 31P NMR, NaOH/EDTA, terrestrial, sulfide, speciation, bioavailability, paramagnetic, humus, boreal, tropical, multi-dimensional, agroforestry, chronosequence
National Category
Physical Chemistry
Research subject
Physical Chemistry
Identifiers
URN: urn:nbn:se:umu:diva-93409ISBN: 978-91-7601-132-4 (print)OAI: oai:DiVA.org:umu-93409DiVA: diva2:748881
Public defence
2014-10-17, KBC-huset, Stora hörsalen, KB3B1, KBC huset, s-90187, Umeå, 10:00 (English)
Opponent
Supervisors
Note

I delarbete III har titel och författaruppgifter förändrats.

Available from: 2014-09-26 Created: 2014-09-19 Last updated: 2014-09-24Bibliographically approved
List of papers
1. High resolution characterization of organic phosphorus in soil extracts using 2D 1H-31P NMR correlation spectroscopy
Open this publication in new window or tab >>High resolution characterization of organic phosphorus in soil extracts using 2D 1H-31P NMR correlation spectroscopy
Show others...
2012 (English)In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, no 7, 3950-3956 p.Article in journal (Refereed) Published
Abstract [en]

Organic phosphorus (P) compounds represent a major component of soil P in many soils and are key sources of P for microbes and plants. Solution NMR (nuclear magnetic resonance spectroscopy) is a powerful technique for characterizing organic P species. However, <sup>31</sup>P NMR spectra are often complicated by overlapping peaks, which hampers identification and quantification of the numerous P species present in soils. Overlap is often exacerbated by the presence of paramagnetic metal ions, even if they are in complexes with EDTA following NaOH/EDTA extraction. By removing paramagnetic impurities using a new precipitation protocol, we achieved a dramatic improvement in spectral resolution. Furthermore, the obtained reduction in line widths enabled the use of multi-dimensional NMR methods to resolve overlapping <sup>31</sup>P signals. Using the new protocol on samples from two boreal humus soils with different Fe contents, two-dimensional <sup>1</sup>H-<sup>31</sup>P correlation spectra allowed unambiguous identification of a large number of P species based on their <sup>31</sup>P and <sup>1</sup>H chemical shifts and their characteristic coupling patterns, which would not have been possible using previous protocols. This approach can be used to identify organic P species in samples from both terrestrial and aquatic environments, increasing our understanding of organic P biogeochemistry.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2012
National Category
Environmental Engineering Environmental Sciences related to Agriculture and Land-use
Identifiers
urn:nbn:se:umu:diva-53091 (URN)10.1021/es204016h (DOI)000302850400048 ()22394413 (PubMedID)
Available from: 2012-03-13 Created: 2012-03-13 Last updated: 2017-12-07Bibliographically approved
2. Soil organic phosphorus transformations in a boreal forest chronosequence
Open this publication in new window or tab >>Soil organic phosphorus transformations in a boreal forest chronosequence
Show others...
2013 (English)In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 367, no 1-2, 149-162 p.Article in journal (Refereed) Published
Abstract [en]

Background and Aims Soil phosphorus (P) composition changes with ecosystem development, leading to changes in P bioavailability and ecosystem properties. Little is known, however, about how soil P transformations proceed with ecosystem development in boreal regions. Methods We used 1-dimensional 31P and 2-dimensional 1H, 31P correlation nuclear magnetic resonance (NMR) spectroscopy to characterise soil organic P transformations in humus horizons across a 7,800 year-old chronosequence in Västerbotten, northern Sweden. Results Total soil P concentration varied little along the chronosequence, but P compounds followed three trends. Firstly, the concentrations of DNA, 2-aminoethyl phosphonic acid, and polyphosphate, increased up to 1,200–2,700 years and then declined. Secondly, the abundances of α– and β—glycerophosphate, nucleotides, and pyrophosphate, were higher at the youngest site compared with all other sites. Lastly, concentrations of inositol hexakisphosphate fluctuated with site age. The largest changes in soil P composition tended to occur in young sites which also experience the largest shifts in plant community composition. Conclusions The apparent lack of change in total soil P is consistent with the youth and nitrogen limited nature of the Västerbotten chronosequence. Based on 2D NMR spectra, around 40 % of extractable soil organic P appeared to occur in live microbial cells. The observed trends in soil organic P may be related to shifts in plant community composition (and associated changes in soil microorganisms) along the studied chronosequence, but further studies are needed to confirm this.

Place, publisher, year, edition, pages
Springer, 2013
Keyword
Podzolization, 1D 31P NMR, 2D 1H, 31P correlation NMR, Inositol hexakisphosphate, Ribonucleic acid (RNA), Västerbotten chronosequence
National Category
Chemical Sciences
Identifiers
urn:nbn:se:umu:diva-71214 (URN)10.1007/s11104-013-1731-z (DOI)
Available from: 2013-05-23 Created: 2013-05-23 Last updated: 2017-12-06Bibliographically approved
3. Effect of Trees on Forms of Soil Phosphorus in an Agroforestry Parkland in Burkina Faso
Open this publication in new window or tab >>Effect of Trees on Forms of Soil Phosphorus in an Agroforestry Parkland in Burkina Faso
Show others...
2014 (English)Manuscript (preprint) (Other academic)
Abstract [en]

Phosphorus is commonly a limiting nutrient for crop production, especially in highly weathered tropical soils. In two semi-arid areas in Burkina Faso with high and low aluminum and iron content respectively, we studied the effect of scattered trees within cropping fields (an agroforestry system called “parklands”) on soils from two areas with high and low aluminum and iron content, respectively. The study focused on different P forms using liquid-state 31P NMR, and their relation to soil chemical properties, determined by XRF. We hypothesized that i) There is generally a difference in P forms between under canopies and in openings outside canopies due to higher input and turnover of organic material close to trees; ii) Close to trees there are more P forms of microbial origin due to the increased activity of the microbial community; iii) This difference is more pronounced in the area with higher content of aluminum and iron. We took topsoil samples under tree canopies as well as outside tree canopies. Our results showed that there were generally low levels of organic carbon and P, but under the canopies of the scattered trees the levels were higher. 31P-NMR showed that soil P was composed of similar ratios of inorganic and organic P as has been observed in other ecosystems, and that the organic P pool was composed of P species commonly observed in soils. NMR also revealed that areas outside the canopies had a less diverse P composition. In the area with high Al/Fe content, microbial activity under trees had a more pronounced effect on the soil P composition, by significantly increasing the amounts of P species of biological origin. In conclusion, the study confirmed the importance of soil organic matter and trees for P availability in semi-arid tropical ecosystems.

Publisher
58 p.
Keyword
phosphorus, 31P NMR, agroforestry, multivarate, nutrients, sub-sahelian
National Category
Physical Chemistry Geosciences, Multidisciplinary
Research subject
Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-93378 (URN)978-91-7601-132-4 (ISBN)
Available from: 2014-09-19 Created: 2014-09-18 Last updated: 2014-09-30Bibliographically approved
4. Changes in organic phosphorus composition in boreal forest humus soils: the role of iron and aluminium
Open this publication in new window or tab >>Changes in organic phosphorus composition in boreal forest humus soils: the role of iron and aluminium
Show others...
2012 (English)In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 108, no 1-3, 485-499 p.Article in journal (Refereed) Published
Abstract [en]

Organic phosphorus (P) is an important component of boreal forest humus soils, and its concentration has been found to be closely related to the concentration of iron (Fe) and aluminium (Al). We used solution and solid state 31P NMR spectroscopy on humus soils to characterize organic P along two groundwater recharge and discharge gradients in Fennoscandian boreal forest, which are also P sorption gradients due to differences in aluminium (Al) and iron (Fe) concentration in the humus. The composition of organic P changed sharply along the gradients. Phosphate diesters and their degradation products, as well as polyphosphates, were proportionally more abundant in low Al and Fe sites, whereas phosphate monoesters such as myo-, scyllo- and unknown inositol phosphates dominated in high Al and Fe soils. The concentration of inositol phosphates, but not that of diesters, was positively related to Al and Fe concentration in the humus soil. Overall, in high Al and Fe sites the composition of organic P seemed to be closely associated with stabilization processes, whereas in low Al and Fe sites it more closely reflected inputs of organic P, given the dominance of diesters which are generally assumed to constitute the bulk of organic P inputs to the soil. These gradients encompass the broad variation in soil properties detected in the wider Fennoscandian boreal forest landscape, as such our findings provide insight into the factors controlling P biogeochemistry in the region but should be of relevance to boreal forests elsewhere.

Place, publisher, year, edition, pages
Springer, 2012
Keyword
Solution 31P NMR spectroscopy, Solid state 31P NMR, Sorption, Groundwater discharge, Groundwater recharge, Betsele
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-44955 (URN)10.1007/s10533-011-9612-0 (DOI)000300659300031 ()
Available from: 2011-06-15 Created: 2011-06-15 Last updated: 2017-12-11Bibliographically approved

Open Access in DiVA

Analysis and speciation of organic phosphorus in environmental matrices: Development of methods to improve 31P NMR analysis(1442 kB)807 downloads
File information
File name FULLTEXT01.pdfFile size 1442 kBChecksum SHA-512
6def99db4eae61212c672e1b32a6db259a7c3770ce7ad81e16a860519faab4c678f9ac3e2b45ddb9c4225cdbb9112ac11df608f614ebdb758e5afaef2ba58e20
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Vestergren, Johan
By organisation
Department of Chemistry
Physical Chemistry

Search outside of DiVA

GoogleGoogle Scholar
Total: 807 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 667 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf