Relation between rainfall and phytoplankton community in Daechung reservoir = 대청호에서 강우와 식물플랑크톤 군집의 관계

Abstract

The phytoplankton community, environmental factors, and rainfall were investigated from July to October in 2001 and 2003 on Dam site in Daechung Reservoir. The monthly average rainfall in the investigated period were 91.3 and 265.3 mm in 2001 and 2003, respectively. The maximum chlorophyll a concentration was observed higher at 131.5 μg L^(-1) in 2003 than at 45.41 μg L^(-1) in 2001. The cyanobacterial number in 2001 was counted up to over 200,000 cells mL^(-1), which was much higher than the maximum number of 49,000 cells mL^(-1) in 2003. The relative abundance of cyanobacteria in the phytoplankton community was about 97% in 2001 and 74% in 2003. Microcystis spp. were absolutely dominant species in 2001, while a couple of cyanobacteria such as Oscillatoria spp., Phormidium spp. Chroococcus spp. and Microcystis spp. were dominant species in 2003. Consequently, it seemed that rainfall affected the diversity of phytoplankton species and decreased the density of bloom-forming cyanobacteria.