During the spring and fall of 1994 and winter of 1995, the exposure time of periphyton biomass on the artificial substrata at 10 headwater streams in the southeastern Korea was evaluated in 7-14 day interval. In the streams with low periphyton biomass (chl a: 2-4 ㎎/㎡) in natural rocks, biomass of artificial substrata (unglazed the: 3.7 × 9.5 × 2 ㎝) exceeded that of the natural rocks after 28 days, while sites with high biomass (chl. a: 20-60 ㎎/㎡) in natural rocks showed slower biomass accumulation after 40 days. Due to the high light input and temperature in a partially shaded mountain stream, development of periphyton biomass in spring occurred faster than that of winter. In general, development of periphyton biomass placed on artificial substrata took 4-5 weeks in spring and at least 6 weeks in winter to reach the natural level.

• 주기재(부산대학교 생물학과) | Gea-Jae Joo (Dept. of Biology, Pusan National University)
• 하경(부산대학교 생물학과) | Kyong Ha (Dept. of Biology, Pusan National University)
• 김현우(부산대학교 생물학과) | Hyun-Woo Kim (Dept. of Biology, Pusan National University)