Diatom diversity in some hot springs of northern Thailand

Abstract Diversity of hot spring diatoms in northern Thailand was studied. Forty-six diatom species were identified in eight localities. The dominant species according to high relative abundance were Diatomella balfouriana (41.7%), Achnanthidium exiguum (20.9%) and Anomoeoneis sphaerophora (11.2%). Moreover, Caloneis molaris, Craticula acidoclinata, Navicula subrhynchocephala and Pinnularia saprophila were recorded as species new to Thailand. The NMDS ordination revealed variation in species composition of eight different hot springs and correlation with the existing environmental variables. Silicon dioxide (SiO2), pH, conductivity, water temperature and total hardness were statistically significant factors affecting relative abundance of Achnanthidium exiguum, Amphora montana, Caloneis aequatorialis, Cocconeis placentula, Craticula cuspidata, Diploneis elliptica, Gomphonema affine, Gomphonema augur, Halamphora fontinalis, Planothidium lanceolatum, Pinnularia abaujensis, Sellaphora lanceolata and Stauroneis anceps.