A Study on the Phytoplankton in the Paldang Dam Reservoir II. The Changes of Phytoplankton Species Composition

Algae > Volume 11(2); 1996 > Article

Algae 1996;11(2): 217-229.

Yoon-Kyung Chang, Sook-Lye Jeon

Department of Biology, Sookmyung Women's University

ABSTRACT

Changes of phytoplankton species composition in the Paldang Dam Reservoir were investigated and compared with the data reported since the construction of the Paldang Dam in 1972. Collections were made at four stations in the Paldang Dam Reservoir from April 1994 to October 1995. Diatoms were not included in this report. A total of 112 taxa belonging to 6 phyla, 7 classes, 11 orders, 22 families, 54 genera, 107 species and 5 varieties were identified. The most abundant algal group was Chlorophyta with 88 taxa, followed by Cyanophyta with 9 taxa, 5 taxa of Chrysophyta exclusive of diatoms, 4 taxa each of Euglenophyta and Phrrophyta and 2 taxa of Cryptophyta. Species of Chlorophyta such as Pandorina morum, Chlorella vulgaris, Sphaerocystis schroeteri, Scenedesmus maximus, Scenedesmus grahneisii, Coelastrum polychorum, Micractinium pusillum, Dictyosphaerium anomallum dominated during the spring and summer in 1994. Species of Cyanophyta; Anabaena spiroides, Merismopedia tenuissima, Aphanocapsa sp. were abundant from June to August. The total cell number was highest in August 1994 and dropped sharply in October which became lowest in December through February, then gradually increased from April to August. Aphanocapsa, Merismopedia, Oscillatoria, Coelastrum and Scenedesmus contributed to the highest cell number in August 1994. The dominant algal group during 1980's was Bacillariophyceae but Chlorophyta and Cyanophyta increased rapidly and shifted the component of dominant species from Bacillariophyceae to Bacillariophyceae-Chlorophyta and Cyanophyta complex in 1990's. This indicates the gradual eutrophication of the Paldang Dam Reservoir.

Key words: Chlorophyta, Cyanophyta, Paldang Dam Reservoir, Phytoplankton, standing crops