Evaluation of Nutrient Release from Sediments of Artificial Lake

Abstract

This study examined nutrient fluxes between sediment and water with a laboratory-scale benthic chamber. This research targeted an artificial lake that had undergone water-quality problems. Two sites at Lake Asan, Site A in the vicinity of the dam and Site B at the inflow of the lake, were selected and characteristics of the sediments and their influence on the water quality of the lake were evaluated. Most of the inorganic phosphorus in the study area was in the form of apatite and nonapatite phosphorus (91.9% of Site A, 83.3% of Site B). Site B, with a fast-stream velocity, had larger particle size, smaller nutrient level, and smaller amounts of inorganic phosphorus than Site A. The benthic chamber experiment showed that overall fluxes of Site A were as follows: ammonia is 0.003 μmol cm-2 day-1, nitrate is -0.067 μmol cm-2 day-1, and phosphate is 1.049 nmol cm-2 day-1. Site B showed an increase in phosphate concentration after a dissolved oxygen (DO) drop (<3 mg/l), which resulted in smaller negative...