A Flora of Scale-Bearing Chrysophytes in the South Basin of Lake Biwa and Seta River, Japan

Abstract

 Mallomonas and Synura belonging to scale-bearing chrysophytes are known for causing taste and odour problems in water supplies. Therefore, scale-bearing chrysophytes from the south basin of Lake Biwa and Seta River that are the source of water supplies in the Kansai area were investigated between October 2022 and November 2024. A total 31 species and 1 variety; 20 species and 1 variety of Mallomonas, 2 species of Synura, 6 species of Spiniferomonas, 1 species of Chrysosphaerella, and 2 species of Paraphysomonas were found. Among them, Mallomonas hamata and M. multiunca were new to Japan, and M. acaroides var. obtusa, M. areolata, M. retifera and Spiniferomonas alata were first reported from Lake Biwa and Seta River. Mallomonas caudata, M. elongata, M. portae-ferreae, M. tonsurata, Spiniferomonas bourrellyi, S. trioralis and Paraphysomonas vestita were found in many samples of four seasons.