Dynamics of Phytoplankton Community in Lake Chungju

Algae > Volume 13(3); 1998 > Article

Algae 1998;13(3): 339-354.

Jee Hwa Kim, Young Hwan Kim, In Kyu Lee

Department of Biology, Seoul National University, Department of Biology, Chungbuk National University

ABSTRACT

Species composition and standing crops of phytoplankton at five stations in Lake Chungju were investigated monthly from January 1993 to December 1994. A total of 175 taxa (38 Cyanophyta, 79 Chlorophyta, 49 Chrysophyta, 3 Pyrrhophyta and 6 Euglenophyta) was identified. Among them, 59 species were found at all the stations, While 45 species were only at a single station. The number of species was most abundant at station 1 in down-stream (127 spp.), and the poorest at station 4 in up-stream station (75 spp.). Number of species, as a whole, showed the highest during summer to mid-autumn and decreased gradually since late autumn until early spring. The standing crops of phytoplankton ranged 61.2 - 8,305.6 x 10 super(3) cells/l, and averaged 1,113.2 x 10 super(3) cells/l in 1993 and 1,316.2 x 10 super(3) cells/l in 1994. The minimum value was recorded in March 1993 (214.1 x 10 super(3) cells/l), and the maximum in September 1994 (4,585.7 x 10 super(3) cells/l) due to the blue-green algal blooming. Dominant species determined by standing crops were 29 species. They showed a clear seasonal succession in this lake. Diatoms contributed the proportion of standing crops significantly during winter and spring, while blue-green algal and green algal were during summer and autumn. Species diversity index (H') of phytoplankton community on an annual average was 1.52 in 1993 and 1.65 in 1994. The highest value was recorded in June, while the lowest from April to May due to the diatom blooming and during July to September due to the blue-green algal blooming. The species diversity was generally higher at a down-stream station than at up-to middle-stream stations.

Key words: dominant species, Lake Chungju, phytoplankton, species composition, standing crops