• Korean Journal of Environmental Biology
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• v.18 no.3
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• pp.347-353
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• 2000

Standing crops of freshwater phytoplankton was studied from October 1998 to September 1999 in Hyendo, Maam, Jangam, and Napo of Kumgang River. Standing crops peaked in July in Hyendo $(39.5{\times}10^3Cells ml^{-1}), Maam (112.1{\times}10^3Cells ml^{-1}), and Jangam (125.5{\times}10^3Cells ml^{-1}), while in August in Napo (288.6{\times}10^3Cells ml^{-1}), respectively. The standing crops ranged less than 5,000 cells ml^{-1} in most of months in Hyendo and Maam, while more than 5,000 cells ml^{-1}$ throughout the year in Napo, Jangam's standing crops being intermediate. Total standing crops throughout the year increased with downstream; the standing crops of Napo was 9.6 times higher than that of Hyendo. The standing crops peaked from spring to early summer in Jangam and peaked in other seasons in Napo. The small centric diatoms Cyczotella spp., Stephanodiscus spp. and filamentous diatoms Aulacoseira spp. played an important role to form the peak of standing crops.