高優占度珪藻による有機汚濁度の判定(2). Caloneis, Cocconeis, Cyclotella, Cymbella, Diatoma, Eunotia, Fragilaria, Gomphoneis, Gomphonema を第1位種とする群集

抄録

Ecological characteristics of the diatom assemblage in which the predominating taxon belongs to Cyclotella, Cymbella, Diatoma, Fragilaria, Gomphoneis or Gomphonema are the following.
Cyclotella: They occur in oligosaprobic waters with 50-84 in DAIpo marks, when its second taxon is a saproxenous taxon. They also occur in polluted waters with less than 29 in DAIpo marks, when its second taxon is a saprophilous taxon.
Cymbella, Diatoma and Gomphoneis: They occur in clean water with over 50 in DAIpo marks respectively. When the predominating taxon is Cymbella minuta var. minuta, C. sinuata var. sinuata or Gomphoneis quadripunctatum respectively, they are commonly found in clean flowing waters with over 70 in DAIpo marks.
Fragilaria: The assemblages, in which the predominating taxon belonging to Fragilaria except F. construens var. veneta and F. pinnata var. lancettula, occur in clean standing waters with over 50 in DAIpo marks. F. vaucheriae var. capitellata occurs in very clean waters with over 70 in DAIpo marks as the predominating taxon.
Gomphonema: The assemblages in which the predominating taxon is G. vibrio and its varieties occur in clean waters with over 50 in DAIpo marks. However, when G. angustatumorG. parvulum with its varieties is the most abundant respectively, it appears in polluted waters with less than 49 in DAIpo marks.