Abstract
Experimental study was carried out in Lake Abashiri where is brackish lake with double-layered formation of freshwater and saltwater. In order to reduce anearobic salt water layer, we installed the gas dissolving apparatus (WEP) in the actual waters. And we obserbed water quality change by the oxygenation. As a result of oxygen supply for two months, dissolved oxygen was increased around the equipment, but influenced area was very small. It was confirmed that oxygen consumption by hydrogen sulfide was large then dissolved oxygen could not be detected. On the other hand, solid sulfur was generated by oxygen supply and then the turbidity was rised. Therefore, when the turbidity is assumed to be a tracer, it is confirmed that the oxygen supply effect expanded to about 120 m square on the bottom water flow. From the results of the water quality analysis, it was cleared that the reduction of hydrogen sulfide with oxygen supply of WEP further phosphorus and nitrogen were reduced. It suggested that detoxification of specific elevation layer is possible in the anearobic brackish lake additionaly nutrient salt is possible to reduce.
