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  • 1.
    Sundqvist, Maja K.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department of Forest Ecology and Management, SLU, Umeå, Sweden.
    Wardle, David A.
    Department of Forest Ecology and Management, SLU, Umeå, Sweden.
    Vincent, Andrea
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Giesler, Reiner
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Contrasting nitrogen and phosphorus dynamics across an elevational gradient for subarctic tundra heath and meadow vegetation2014Ingår i: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 383, nr 1-2, s. 387-399Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study explores soil nutrient cycling processes and microbial properties for two contrasting vegetation types along an elevational gradient in subarctic tundra to improve our understanding of how temperature influences nutrient availability in an ecosystem predicted to be sensitive to global warming. We measured total amino acid (Amino-N), mineral nitrogen (N) and phosphorus (P) concentrations, in situ net N and P mineralization, net Amino-N consumption, and microbial biomass C, N and P in both heath and meadow soils across an elevational gradient near Abisko, Sweden. For the meadow, NH4 (+) concentrations and net N mineralization were highest at high elevations and microbial properties showed variable responses; these variables were largely unresponsive to elevation for the heath. Amino-N concentrations sometimes showed a tendency to increase with elevation and net Amino-N consumption was often unresponsive to elevation. Overall, PO4-P concentrations decreased with elevation and net P immobilization mostly occurred at lower elevations; these effects were strongest for the heath. Our results reveal that elevation-associated changes in temperature can have contrasting effects on the cycling of N and P in subarctic soils, and that the strength and direction of these effects depend strongly on dominant vegetation type.

  • 2.
    Vestergren, Johan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Vincent, Andrea G
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Jansson, Mats
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Persson, Per
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Istedt, Ulrik
    Department of Forest Ecology & Management, SLU, Umeå, Sweden.
    Gröbner, Gerhard
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Giesler, Reiner
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Schleucher, Jürgen
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    High resolution characterization of organic phosphorus in soil extracts using 2D 1H-31P NMR correlation spectroscopy2012Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, nr 7, s. 3950-3956Artikel i tidskrift (Refereegranskat)
    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.

  • 3.
    Vincent, Andrea G
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Schleucher, Jürgen
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Gröbner, Gerhard
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Vestergren, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Persson, Per
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Jansson, Mats
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Giesler, Reiner
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Changes in organic phosphorus composition in boreal forest humus soils: the role of iron and aluminium2012Ingår i: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 108, nr 1-3, s. 485-499Artikel i tidskrift (Refereegranskat)
    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.

  • 4.
    Vincent, Andrea G.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Sundqvist, Maja K.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Wardle, David A.
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Giesler, Reiner
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Bioavailable Soil Phosphorus Decreases with Increasing Elevation in a Subarctic Tundra Landscape2014Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, nr 3, s. e92942-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Phosphorus (P) is an important macronutrient in arctic and subarctic tundra and its bioavailability is regulated by the mineralization of organic P. Temperature is likely to be an important control on P bioavailability, although effects may differ across contrasting plant communities with different soil properties. We used an elevational gradient in northern Sweden that included both heath and meadow vegetation types at all elevations to study the effects of temperature, soil P sorption capacity and oxalate-extractable aluminium (Al-ox) and iron (Fe-ox) on the concentration of different soil P fractions. We hypothesized that the concentration of labile P fractions would decrease with increasing elevation (and thus declining temperature), but would be lower in meadow than in heath, given that N to P ratios in meadow foliage are higher. As expected, labile P in the form of Resin-P declined sharply with elevation for both vegetation types. Meadow soils did not have lower concentrations of Resin-P than heath soils, but they did have 2-fold and 1.5-fold higher concentrations of NaOH-extractable organic P and Residual P, respectively. Further, meadow soils had 3-fold higher concentrations of Al-ox + Feox and a 20% higher P sorption index than did heath soils. Additionally, Resin-P expressed as a proportion of total soil P for the meadow was on average half that in the heath. Declining Resin-P concentrations with elevation were best explained by an associated 2.5-3.0 degrees C decline in temperature. In contrast, the lower P availability in meadow relative to heath soils may be associated with impaired organic P mineralization, as indicated by a higher accumulation of organic P and P sorption capacity. Our results indicate that predicted temperature increases in the arctic over the next century may influence P availability and biogeochemistry, with consequences for key ecosystem processes limited by P, such as primary productivity.

  • 5.
    Vincent, Andrea G
    et al.
    Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK.
    Turner, BL
    Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancón, Republic of Panama.
    Tanner, EVJ
    Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK.
    Soil organic phosphorus dynamics following perturbation of litter cycling in a tropical moist forest2010Ingår i: European Journal of Soil Science, ISSN 1351-0754, E-ISSN 1365-2389, Vol. 61, nr 1, s. 48-57Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    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.

  • 6.
    Vincent, Andrea G.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap. Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Vestergren, Johan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Gröbner, Gerhard
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Persson, Per
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Centre for Environmental and Climate Research, Lund University, Lund, Sweden.
    Schleucher, Jürgen
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk kemi och biofysik.
    Giesler, Reiner
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Soil organic phosphorus transformations in a boreal forest chronosequence2013Ingår i: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 367, nr 1-2, s. 149-162Artikel i tidskrift (Refereegranskat)
    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.

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