Dynamics of particulate phosphorus in a shallow eutrophic lake

Sci Total Environ. 2016 Sep 1;563-564:413-23. doi: 10.1016/j.scitotenv.2016.04.134. Epub 2016 May 2.

Abstract

We tested the hypothesis that in shallow, eutrophic Lake Kasumigaura, the concentration of particulate phosphorus (PP) is controlled by biogenic P (P in living or dead phytoplankton and bacterial cells), rather than by resuspension of inorganic P in sediment. Increases in wind velocity and turbidity were associated with bottom shear stress exceeding the critical value for the lake (τc=0.15Nm(-2)); this increased turbidity was due to sediment resuspension. However, concentrations of PP; HCl-extractable, reactive P in PP (P-rP); and HCl-extractable, non-reactive P in PP (P-nrP) were not correlated with wind velocity (PP vs. wind velocity: r=0.40, p>0.05). Rather, the P-nrP concentration accounted for approximately 79% of PP, and the concentrations of PP, P-rP, and P-nrP were correlated with the particulate organic carbon (POC) concentration (POC vs. PP: r=0.90, p<0.01; POC vs. P-rP: r=0.82, p<0.01; POC vs. P-nrP: r=0.86, p<0.01). In our (31)P nuclear magnetic resonance spectroscopy results, mononucleotides accounted for the largest proportion among the detected P compound classes. In addition, concentrations of mononucleotides, orthophosphate, and pyrophosphate were significantly higher in samples with high POC concentrations, whereas the DNA-P concentration was not. These results suggest that biogenic P affects PP concentrations more strongly than does sediment resuspension, and the production of biogenic P creates a pool of mononucleotides, a class of easily degradable P, even in shallow, eutrophic Lake Kasumigaura.

Keywords: Biogenic P; Particulate P; Sediment resuspension.

MeSH terms

  • Environmental Monitoring
  • Eutrophication*
  • Geologic Sediments / chemistry*
  • Japan
  • Lakes / chemistry*
  • Particulate Matter / analysis*
  • Phosphorus / analysis*
  • Phosphorus Compounds / analysis*
  • Water Movements
  • Water Pollutants, Chemical / analysis*

Substances

  • Particulate Matter
  • Phosphorus Compounds
  • Water Pollutants, Chemical
  • Phosphorus