청계천의 수질과 부착조류의 계절적 변동

초록

The seasonal variations of water quality and periphyton were investigated in an artificial stream (the Cheonggyecheon Stream) flowing through the Seoul City. TP showed a longitudinal gradient: 10 to 59 μgP L-1 in the upper stream sites, and 15 to 90 μgP L-1 in downstream sites. POP was a major form of TP in the water, occupying over 60%, while the proportion of DIP was less than 10% except for St. 4. N/P atomic ratio ranged from 78 to 554, which implies phosphorus would limit algal growth more than nitrogen. The biomass of periphyton did not show much difference among sites, and it was relatively higher in spring and fall season (10~20 μgChl a cm-2) and lower in August (⁄5 μgChl a cm-2), possibly because biofilms were washed off during spates of summer monsoon. Cyanobacteria was the dominant taxon in the periphyton community throughout the year. The periphyton standing crop can be classified as a nuisance level. It seems that phosphorus level is sufficiently high even though the input water is treated chemically, and modest water velocity (20~90 cm sec-1) and rocky bottom provide optimal conditions for periphyton growth.

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