운문호의 환경특성에 의한 식물플랑크톤 군집구조 변동

Abstract

This study is to clarify the structure and seasonal dynamics of phytoplankton community and environmental factor, and its survey was conducted from April to November 2009, April to November 2010 and April to November 2011 in Lake Unmoon, Korea. During the surveyed period, the water temperature was of the lake was observed low during winter and high during summer. Its dissolved oxygen was high during summer and low during winter. The pH ranged from 7.3 to 10.6. The Chlorophyll-a concentration was high during the fall(September) and low during winter(October). During the survey period, temperature ranged from 11.2℃ to 30.2℃, pH from 7.3 to 10.6, DO from 5.9 mg/L to 12.4 mg/L and chlorophyll-a from 3.1 mg/m3 to 193.9 mg/m3, respectively. A total of 99 species were identified from the samples. Among them, the largest number of species were Bacillariophyceae with 45 species(45.5%), followed by Chlorophyceae with 35 species(35.4%), Cryptophyceae with 11 species(11.1%) and Cyanophyceae with 8 species(8.1%), respectively. Common phytoplankton were identified over seasons, such as Microcystis wesenbergii, Microcystis aeruginosa, Microcystis ichthyoblabe, Microcystis sp., Anabaena sp., Aulacoseira ambigua, Fragilaria crotonensis, Pediastrum duplex var. gracitimum, Coelastrum sp., Peridinium sp., and Dinobryon sp.. The standing crops ranged from 101cellss/mL to 8,122cellss/mL, with a mean value of 1,516cellss/mL during this study. The biomass of phytoplankton increased in spring and summer. At Lake Unmoon, maximun peaks were observed in June and July, 2011. The highest cell density was observed in July, 2011 with 8,122cellss/mL. in which dominant species was Fragilaria crotonensis. The phytoplankton community was dominated by Bacillariophyceae. Cyanophyceae was the second abundant group and Cryptophyceae was the third abundant group. Other different species were found occasionally. Bacillariophyceae was dominated in spring and Cyanophyceae was dominated in summer along with the increase of water temperature. In order to maintain the environment of the lake and secure its resources, a consistent effort should be made to improve the water qualities. Also, the date from Lake Unmoon should be saved and observed to find out the cause of Cyanobacteria water bloom in Lake Unmoon.