Nitzschia paleaeformis and Nitzschia amplectens occurring in strongly acid waters of pH range from 1. 0 to 3. 9 in Japan

Abstract

We have performed a statistical anal y sis on the pH tolerance of 485 diatom taxa in epilithic algal assemblages, collected from 215 freshwater sites, representing a pH gradient ranging from 1.0 to 12.5. In this study,45 Nitzschia taxa occurred. Among them 22 belong to alkaliphilous (16 taxa) or alkalibiontic (6 taxa) taxa, while 21 are circum-neutral taxa. Only two taxa were recognized as acidobiontic taxa. In this paper, we report on the ecological and morphological features of these two strange Nitzschia taxa occurring in the strong acid waters from pH 1.0 to 3.9 in Japan.