Abstract
Diatom assemblages and water quality were investigated at six sites in the hot spring of Oyasukyo gorge. The pH was alkaline and the water temperature was higher than 30°C except at one site. In total, 38 genera and 82 taxa were recorded; the most predominant being Achnanthidium exiguum, which is frequently found in alkaline hot springs. The other taxa of relatively high abundance are as follows: Pinnularia joculata, Diadesmis confervacea, Ulnaria oxyrhynchus, Sellaphora seminulum, Navicula rostellata, and Nitzschia brevissima.
