Abstract
Blue tide is a symbolic phenomenon showing water pollution. While water quality of Osaka Bay is rather bad, occurrence of blue tide has not been reported in the bay. It has been observed that a color of sea surface changed milky green and smelling like hydrogen sulfide in the head of Osaka Bay in 2004. Blue tide has been occurred when strong winds about 10m/s speed was blowing continuously in the landward side. The present study shows results of field observations investigating water quality and generated area of the blue tide and discusses the mechanism of upwelling of anoxic bottom water.
