Algae. 1999; 14(3): 161-167.

An Assessment of Trophic State by LTSI and Phytoplankton Community in Lake Tokdong

Yong Jae Kim

Department of Life Science, Daejin University

This study was investigated to phytoplankton community and trophic state by LTSI in Lake Tokdong from November 1990 to October 1992. Phytoplankton community was identified total 352 taxa, which was composed of 320 species, 28 varieties and 4 forms, belong to 117 genera, 37 families, 6 suborders, 14 orders and 7classes. The standing crops of phytoplankton were ranged from 4.3 × 10 super(4) cells/l to 4.5 × 10 super(5) cells/l. The dominant species were Aulacoseira ambigua, A. distans var. alpigena, A. granulata, Cyclostephanos dubius, Cyclotella pseudostelligera, Chlamydomonas globosa, Tetraedron minimum and Monoraphidium contortum. LTSI were ranged from 3.9 to 11.4 and their trophic states were mesotrophy from February to June 1991, and eutrophy from October 1991 to September 1992. The indexes were higher values than 10 from July to September 1991, and the trophic states of these times were hypertrophy. This tended to be overestimation by the allochthonous suspensoids(silt or clay). Therefore, This lake was assessed from mesotrophic to eutrophic states during investigation

Keywords : eutrophy, Lake Tokdong, LTSI, mesotrophy, phytoplankton community, trophic state