Abstract
The diatom community of brackish water in the Kumano-gawa River Estuary ( Wakayama Prefecture ) was investigated. Examination of cleaned m aterial revealed a total of 75 forms, of which 29 forms seems to be allochthonous in origin. The diatom community was made up of 18-27 forms at each station. Species diversity ( SHANNON-WIENERD I ( bits ) ) was relatively low, and ranged from 2.01 to 2.18. The communities were predominated by Nitzschia frustulum, and significant diatoms were as follows;Achnanthes minutissima, Gomphonema pseudoaugur, Melosira varians, Navicula gregaria, N. mutica, N. neoventricosa, Nitzschia filiformis, N. palea, N. aff.romana, Synedra fasciculata var.truncata.
