Periphytic diatoms of Nakaikemi Wetland, an ancient peaty low moor in central Japan

摘要

The periphytic diatom flora of Nakaikemi Wetland, a peaty low moor located near the Sea of Japan in Fukui Prefecture, central Japan, was studied. This moor was inscribed as a registered wetland under the Ramsar Convention in 2012. We checked a total of 50 diatom samples collected from the surface of filamentous green algae, living/dead spermatophytes, and mud in the moor in May and November, 2008. The water ranged from slightly acidic to alkaline (pH 5.9–8.8), and electrical conductivity also varied greatly among sites (7–32 mS m~(-1)). In all, 297 taxa belonging to 61 genera are listed and illustrated from these samples, although 36 taxa among them have not been identified to species. In terms of taxa richness, the dominant genus was Pinnularia , represented by 35 taxa, followed by Navicula (24 taxa), Nitzschia and Gomphonema (23 taxa each), and Sellaphora (21 taxa). Several brackish and/or marine diatoms occurred in the samples although the water was fresh. Navicula americana var. moesta Temp. et H.Perag. is raised to species level with its transfer to the genus Sellaphora , as S. moesta (Temp. et H.Perag.) Ohtsuka comb. nov.