The aim of this investigation was to study the temporal variation in phosphorus release from the sediments and its influence on water quality of stratified lakes. The concentrations of soluble reactive phosphorus (SRP), calcium and sulfate in the interstitial water and the pH in the wet sediments of dimictic lakes were investigated during the spring circulation and at the end of summer stratification. Multiple regression analysis using the calculated diffusive fluxes of SRP out of the sediments and the morphometric characteristics of the lakes (reduced water depth), explained 73 % of the variance of the SRP-accumulation in the hypolimnia during summer stagnation. At the end of summer stratification diffusive fluxes of SRP out of the sediments increased and pH-values and sulfate-concentrations decreased at the sediment surface (0–2 cm) and in the hypolimnia. The maximum diffusive flux of SRP was calculated to be 5.8 mg/m2/d at the end of summer stagnation. Probable reasons for these higher diffusive fluxes of SRP at the end of summer stagnation are higher supply of labile organic matter and thereby higher mineralization rates, lower redox potential and thus higher dissolution of redox sensitive P-binding forms and/or dissolution of phosphorus being bound to Ca-phases at lower pH.
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- Variations of Phosphorus Release from Sediments in Stratified Lakes
- Springer Netherlands