Sediment phosphorus release during stratification in polymictic Lake Rotorua, New Zealand

摘要

Nutrients released across the sediment-water interface during stratification and deoxygenation events may contribute a significant fraction of the total nutrient requirements for primary production in shallow lakes. In eutrophic lakes, internal nutrient cycling may sustain high nutrient concentrations regardless of external nutrient load reductions (Marsden 1989, Anderson & Ring 1999). For example, in eutrophic Lake Rotorua, New Zealand, little change in nutrient concentrations and trophic status has occurred over the last two decades despite sewage diversion in 1991 (Burns 1997). Previous predictions of water quality in this lake indicate that internal nutrient loads are likely to be a significant component of the total nutrient budget (Rutherford et al. 1996). Our objective was to quantify sediment phosphorus release in polymictic Lake Rotorua during a stratification event.