소양호 부영양화에 따른 N/P비의 변화와 남조류 Bloom

다국어 초록 (Multilingual Abstract)

After the first advent in 1986 two species of Anabaena spiroides and A. macrospora showed increasing dominacy year by year, which is thought to be enhanced by the increase of phosphorus concentration and the decrease of N/P ratio caused mainly by the phosphorus discharge from fishfarms within the lake. The bluegreen algal bloom in a water without nitrogen depletion is the unique feature in Lake Soyang. Nitratenitrogen was maintained always above 0.5mg N/l throughout the year, though the NO3T/TP ratio decreased from 100 in 1984 to 50 in 1990 due to the increase of phosphorus content. High nitrogen concentration and scarcity of gererocyst in trichomes of Anabaena implies that nitrogen fixing ability is not critical for the bluegreen algal dominance in Lake Soyang. In the bag cultivation of Anabaene, the number of heterocysts increased with the addition of phosphorus which induced nitrogen depletion and the reduction of N/P ratio through algal growth.