Algae. 1995; 10(2): 121-141.

Effects of Cooling System at Power Plant on Marine Algal Vegetation

Young Hwan kim, Sang Il Choi

Department of Biology, Chungbuk National University

Seasonal changes of species composition and biomass of the intertidal benthic marine algae were investigated from October 1993 to August 1994, at the four sites of Ulchin nuclear power plant and adjacent area, eastern coast of Korea. Morphometric comparisons of algal populations occurring in the intake and discharge canals have also been carried out in order to examine the effects of cooling systems at the power plant on marine algae. Length, number of maximum branching, width of upper, middle and lower frond, and biomass of individuals were selected as morphometric parameters. A total of 117 species of algae (4 blue-green, 15 green, 22 brown and 76 red algae) was found during the study period. The largest number of algal species (87) was observed at the reference site, Chukpyon, whereas the smallest number of species (44) was fund from the discharge canal of the power plant. Mean biomass per unit area showed maximum at the outside of intake canal as 778 g dry wt m super(-2) and minimum at the inside of intake canal as 276 g dry wt m super(-2). Marine algal biomass, on the whole, showed minimum in autumn (371 g dry wt m super(-2) in average) and increased through winter to a spring peak (764 g dry wt m super(-2) n average). In general, the dominant species in biomass were Corallina spp. and Sargassum micracanthum throughout the year. Inside of intake canal, however, was an exception, for here Chondria crassicaulis and Pachymeniopsis elliptica were observed as dominant species in biomass proportion. Particularly, Padina arborescens occurred exclusively at the inside of discharge canal throughout the study period. Highest species diversity (H') was recorded at the inside of intake canal and minimum was noted at the inside of discharge canal. In the case of Priontis cornea growing at the inside of intake canal, almost all the morphometric parameters of population were significantly higher than those of the inside of discharge canal during autumn and winter. On the contrary, during spring and summer, population of the discharge canal was significantly greater than those of the intake. Gymnogongrus flabelliformis, however, displayed greater morphometric parameters in the discharge canal than in the intake during the study period. It is clear that the characteristic marine algal community is developed in the area affected by the thermal discharges; i.e. low species richness and low species diversity. Nevertheless, it is worthwhile to note that elevated temperatures exert differential effects depending on the algal populations.

Keywords : benthic marine algae, species composition, biomass, morphometry, nuclear power plant, cooling system