According to the environmental fluctuations, it was changed with not only physico-chemical factors but also biological species composition and standing crops. In this water system, the authors investigated the total standing crops, standing crops and ...
According to the environmental fluctuations, it was changed with not only physico-chemical factors but also biological species composition and standing crops. In this water system, the authors investigated the total standing crops, standing crops and composition ratio of each morphotype of Pediastrum clathratum from Nov. 1990 to Oct. 1991 and established the ecotype. Physico-chemical factors were changed uniformly in the steady state water system, but changed dramatically as the nonsteady state from June to Oct. 1991 by a torrential rain. Changes of standing crops of P. clathratum were ranged from the 7.0×10 exp (4)unit/ℓ in Nov. 1990 to 1×10 exp (2)unit/ℓ in Aug. and Sept. 1991. Of seasonal changes of each morphotype, A-2 morphotype occurred during the all months and showed the highest standing crops and composition ratio. Therefore, the authors treat A -2 morphotype as the ecotype (e.g. P. biwae form) by the seasonal changes of steady state, eury-adaptation, the highest standing crops and composition ratio.