一河川に連なるダム湖の光合成量  [in Japanese] The Photosynthesis in Five Dams Belonging to a River  [in Japanese]

The photosynthesis and photosynthetic activity were measured in five dams of the Yahagi River where was located on central Japan. A count of 0.00 to 0.729mg O_2・1^<-1>・hr^<-1> in the values of photosynthesis was obtained and the photosynthetic value from 0.00 to 145mg O_2・mg Chl. a^<-1>・hr^<-1> was also measured. It was found that the eutrophication was the highest period of the previous data in five dams of the Yahagi River. The appearances of red tide were recognized in the Yahagi dam on October and November 1989. In this case, the values of photosynthesis was 0.49 to 1.27mg O_2・1^<-1>・hr^<-1> and the photosynthetic activity was 2.64 to 4.17mg O_2・mg Chl.a^<-1>・hr^<-1>. The photosynthetic activity was generally low in these dams of Yahagi River when a high photosynthesis was obtained. This is an interesting problem concerning the eutrophication.