The seasonal changes and composition of phytoplankton of the Choonsan reservior were studied from November 1990 to October 1991. 195 taxa which belong to 65 genera, 150 species, 40 varieties and 1 forms were identified. Species number during summer monthes was higher than that of other seasons. Standing crops of phytoplankton were varied from 7.8 × 10 exp (5) cells/ℓto 2.2 × 10 exp (6) cells/ℓ The dominant species were Cryptomonas erosa and Trachelomonas uolvocina. Chlorophyll a contents of phytoplankton was varied from 1.36 ㎍/ℓto 127.46 ㎍/ℓ. The biotic indices of phytoplankton were very similar among three sites. Saprobien-system by index of species diversity suggests that the Choonsan reservior belongs to the oligosaprophic.

• 김종원 | Jong Won Kim
• 이학영 | Hak Young Lee
• 김맹기 | Maeng Ki Kim
• 김정아 | Jeong Ah Kim