DENSITY STRATIFICATION AND WATER QUALITY IN A VERTICAL SECTION ALONG TAKESAKI-OHMUTA LINE OF ARIAKE SEA

Abstract

Water quality in a vertical section along Takesaki-Ohmuta line of Ariake Sea was observed under diverse vertical density distributions in the summer season of 2003. A high turbidity layer is formed near the bottom during the ebb tide period. The density stratification suppresses the mixing between the upper layer and the lower one. Both the generation of the high turbidity layer and the density stratification induce the rapid consumption of dissolved oxygen over the whole of the lower layer. Fluxes of Chl.a and SS take large values in the western area of Ariake Sea even under non-stratification field. When the stratification due to the freshwater is formed, primary production in the west area of Ariake sea become larger then that in the east area, and the difference of the between the fluxes west and east areas may become more apparent.