Forms of Phosphorus in Palustrine Wetland Soils: a 31Ρ NMR Study.

Nutrient pollution, from both diffuse agricultural applications and point source contamination is a pressing concern for ecosystem integrity across the globe, with P considered of prime concern to many freshwater aquatic and wetland systems. The biological sequestration and turnover of P has long been recognized as an important component of wetland P cycling, with operationally defined ‘organic P’ often found to constitute the majority of total P within wetland soils. The functional nature of this P dictates interaction with both abiotic and biotic components, influencing both long term stability and biological availability. The application of analytical techniques, such as solution ³¹Ρ 

Studies to date have shown palustrine wetland soils, to contain a P composition distinctly different to the more highly studied terrestrial soils, yet such studies have been limited to a few distinct systems.  Within this study we used solution ³¹Ρ NMR to evaluate the P composition of surface soils (0 – 10 cm) within 28 diverse freshwater wetlands from a range of geographical settings. We concluded that while P composition was independent of direct influence from wetland vegetation or climatic setting, basic biophysical characteristics could be used to group sites in terms of the P forms found. The simple delineation of wetland sites with respect to pH and organic matter content was enough to show clear distinctions between the nature and proportion of P forms found. Such distinctions included the presence of phosphonates, the proportion of phosphomonoesters to phosphodiesters, the presence of isomers of the phosphomonoester IP₆, as well as the presence of significant concentrations of polyphosphates.