High-resolution, two-dimensional measurement of dissolved reactive phosphorus in sediments using the diffusive gradients in thin films technique in combination with a routine procedure

Environ Sci Technol. 2011 Nov 15;45(22):9680-6. doi: 10.1021/es202785p. Epub 2011 Oct 26.

Abstract

Dissolved reactive phosphorus (DRP) is the most available P form in sediments and often directly controls phytoplankton blooms in aquatic systems. In this study, a novel procedure was developed for two-dimensional (2D) measurement of DRP in sediments at a spatial resolution of 0.45 mm using the diffusive gradients in thin films (DGT) technique with a revised high-capacity binding phase (Zr oxide gel). This procedure involves DGT uptake of P in sediments, 2D slicing of the binding gel on a 0.45 × 0.45-mm grid system, elution of P from each gel square with 1 M NaOH, and microcolorimetric determination of DRP in each eluted solution using 384-microwell plates. Measurements of DRP via this procedure were tested in homogeneous solutions and sediments and produced an acceptable error (<20% relative standard deviation) for the analysis once the accumulated mass of P in each gel square reached 1.2 μg cm(-2). This method was successfully applied to produce 2D images of the DRP distribution in sediments with and without the influence of tubificid worm bioturbation, revealing a much more pronounced and localized impact from tubificid worms than that found using a one-dimensional measurement of pore water DRP concentrations at 1-cm resolution.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Diffusion
  • Environmental Monitoring / instrumentation*
  • Environmental Monitoring / methods
  • Gels / chemistry
  • Geologic Sediments / analysis*
  • Phosphorus / analysis*
  • Sensitivity and Specificity
  • Water Pollutants, Chemical / analysis*
  • Zirconium / chemistry

Substances

  • Gels
  • Water Pollutants, Chemical
  • Phosphorus
  • Zirconium
  • zirconium oxide