Time Variation of Concentration of Dissolved Oxygen in Koyama Lake

Abstract

The eluating rate of nutrients from bottom mud in a lake are influenced by dissolved oxygen. Especially the eluating rare of phosphorus under the anaerobic condition is much bigger than that under the aerobic condition. Therefore, it is very important to investigate the characteristics of concentration of dissolved oxygen in a lake, especially period and area of anaerobic condition at the bottom of the lake. Therefore, in Koyama lake, the long time continuos observations of dissolved oxygen were carried out during summer season. Form the observed data, it is found that the anaerobic condition will be able to occur after 2 or 3 days under weak wind condition.