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Title |
Phytoplankton Communities and Water Quality Changesin Uiam Lake and Gongji Stream
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Authors |
이은서(Eunseo Lee) ; 오승수(Seungsoo Oh) ; 김현우(Hyunwoo Kim) ; 김세윤(Seyoon Kim) ; 김나래(Narae Kim) ; 박정안(Jeong-Ann Park) |
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DOI |
https://doi.org/10.15681/KSWE.2026.42.2.151 |
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Keywords |
Algae; Cyanobacteria; Gongji Stream; Seasonal variation; Uiam Lake |
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Abstract |
This study examined seasonal variations in water quality and algal communities in Uiam Lake and Gongji Stream. Water quality generally fell within Class II to III according to regional standards for rivers and lakes. Dissolved oxygen (DO) levels remained above 6.5 mg/L, and pH was stable and slightly alkaline. Electrical conductivity (EC) ranged from 125 to 321 μS/cm between April and August, while biochemical oxygen demand (BOD) tended to rise with increasing temperatures. Total nitrogen (T-N) levels consistently exceeded 2.0 mg/L, and total phosphorus (T-P) was below 0.066 mg/L in spring but increased during the summer months. Chlorophyll-a (Chl-a) concentrations were low, under 2.5 mg/m in March, but gradually increased with rising temperatures. Phycocyanin (PC) concentrations were low (≤0.77 μg/L) in June but rose significantly thereafter. Algal analyses indicated higher cell densities in Uiam Lake, classifying the overall algal assemblage as mesotrophic. Seasonal variations in algal diversity were noted, with greater diatom diversity in spring and increased green algal diversity in summer. Three of the four genera of harmful cyanobacteria were identified, including Microcystis sp.,Anabaena sp., and Oscillatoria sp. Algal-related variables (Chl-a, phycocyanin, and cell density) showed significant positive correlations with several water quality parameters (DO, pH, and BOD). The Uiam Lake water system was influenced by both biotic factors (algal and organic loading) and physicochemical factors. The calculated Trophic State Index ranged from 45 to 60, indicating conditions ranging from mesotrophic to eutrophic.
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