1993년 7월 부터 1994년 6월까지 1년동안 계절별로 4회에 걸쳐, 만경강 상류에 위치하는 3개 상수원수 취수지와 4개 하천지점을 대상으로, 식물플랑크톤군집의 생태학적 특성과 환경요인을 조사한 결과는 다음과 같다. 동정확인된 식물플랑크톤은 총 322분류군으로, 6강 15목 8아목 33과 7아과 81속 263종 52변종 7품종으로 분류할 수 있었으며, 규조류가 135분류군으로 가장 풍부하게 출현하였다. 산정된 총생물량은 1.11×10 exp (7)cells/㎖로서, 여름에 3.16×1010 exp (6)cells/㎖(28.47%)으로 가장 높았는데, 지점별로는 하천에 비해 저수지에서 높은 출현을 보였다. 조사기간중 우점종으로는 Melosira granulata로 총생물량은 4.92×10 exp (5)cells/㎖ 수질을 바탕으로 몇몇의 우점종에 대해 오염내성지수를 부여하였기 때문에 다른 출현종들에 대한 누적적인 의미는 갖는 것은 아니며, 출현빈도의 차이를 오염의 내성차이로 해석하는데 다소 무리가 있다고 판단되었 개 저수지의 생물군집과 환경요인간의 상관성 조사결과, 높은 생물량을 보인 지점 3과 6은 영얌염과 매우 밀접한 관계를 보였으며, 지점 7은 수온이나 용존산소 등의 물리적인 요인과 높은 상관성을 나타냈다. 우점종을 근거로한 저수지의 영양수준은 빈영양에서 부영양의 범위를 보였으며, 지점 3은 여름과 가을에 부영양수준이었다. 오염내성지수는 1-4등급의 범위를 보였으며, Melosira granulata, Synedra ulna, Melosira varians등 3분류군은 보편종으로, Gomphonema olivaceum, Cyclotella meneghniana는 2등급, Achnanthes subsalsa와 Melosira italica var. tenuissima는 3등급 지표종으로, Microcystis aeruginosa는 부영양지표종으로 각각 판단되었다. 이상의 결과로 부터 만경강 상류수계의 식물플랑크톤 군집의 특성과 환경요인을 종합한 수질은 지점 1에서 여름과 가을에 빈부수성(수질1급)과 지점 3에서 여름과 겨울에 α-증부수성(3급)의 범위를 보였으며 전체적으로 β-중부수성(2급)으로 판정할 수 있었다.

Phytoplankton community and its physicochemical parameters were investigated at three reservoirs and four streams in the upper part of the Mankyeong River System from July, 1993 to June, 1994 on seasonal interval. Totally, 322 taxa were classified and composed of 33 families, 82 genera, 263 species , 52 varities and 7 forma Among them, 135 taxa of Bacillariophyceae was the highest record during this study. Total standing biomass of 1.11×10 exp (7)cells/㎖ was enumerated, and the high peak was in summer as 3.16×1010 exp (7)cells/㎖(28.5%), and also, reservoirs more higher than streams in biomass. Melosira granulata was much dominated and totally, 4.9×10 exp (5)cells/㎖ was counted As a whole, nine taxa of fourth species including Cyclotella meneghniana in streams and five taxa with Melosira varians in reservoirs were also domianted Synedra ulna and Melosira granulata were distributed either at stream or reservoirs. Species diversity indices(H` ) were showed the maximum at station 5 as above 2.0 without seasonality and the lowest at station 6 and 7 as below 1.0 in spring and summer. Similarity indices among sampling stations were the peak as 0.58 between station 4 and 5, the lowest between station 6 and 7 located at the same stream. In view of correlation between biological and physicochemical conditions at three reservoirs, station 3 and 6 were more related with organic nutrient, in other hand, station 7 was dependent with physicochemicals such as water temperature and dissolved oxygen. And also, water qualities of station and 6 with regard to total biomass of the major dominant species were ranged from oligotrophic to eutrophic, while station 3 on summer and autumn was eutrophic. The degree of pollution tolerance scores(PTS) was ranged from degree 1 to 4 Several bioindicators newly introduced, three common species were Melosira granulata, Synedra ulna and Melosira varians. Two taxa of Gomphonema olivaceum and Cyclotella meneghniana were showed only in degree 2, and also, two taxa of Achnanthes subsalsa and Melosira italica var. tenuissima were distributed only in degree 3. Microcystis aeruginosa was well dominated at eutrophic state as below degree 3. From this above results, we may evaluate the degree of water quality based on bioloical and physicochemical conditions that station 1 in summer and autumn was oligotrophic state as degree 1, station 3 in summer and winter was α-mesosaprotrophic as degree 3, and totally showed β-mesosaprotropnic as degree 2.