CO2와 수온 증가에 대한 봄철 저수온기 팔당호 식물플랑크톤군집 변화

This study investigated the influence of temperature and CO2 increase on phytoplankton growth and community structure during cold water season (spring) in Lake Paldang, Korea. Four experimental treatments of temperature and CO2 manipulation were prepared in the laboratory batch culture: (1) Control; ambient low temperature (6±2.C) and low CO2 (air level, 400 mg L-1), (2) T1; low temperature and high CO2 (800 mg L-1), (3) T2; high temperature (20±2.C) and low CO2, (4) T3; high temperature and high CO2. Algal growth experiment was carried out for 10 days under the light intensity of 70 μmol m-2 s-1 (L:D=24 : 0). The level of pH decreased in both T1 and T3, due to dissolution of added CO2. The dominant phytoplankton species of ambient water, Cyclotella meneghiniana succeeded to Fragilaria capucina var. gracilis in high-temperature treatment groups (T2 and T3). Cyanobacteria were very rare at the beginning of the experiment, while Oscillatoria limnetica appeared in only high-temperature groups (T2 and T3) at 6~7th day. CO2 addition in ambient temperature (T1) induced the highest phytoplankton growth, and thereby producing the highest average cell density of 3.27±0.33 104 cells mL-1, followed by T2 (2.65±0.26 104 cells mL-1), T3 (2.09±0.16 104 cells mL-1), and Control (1.86±0.13 104 cells mL-1) (F=7.167, p=0.000). In summary, temperature increase changed the phytoplankton community structure and CO2 increase promoted the phytoplankton growth during the cold spring season in Lake Paldang, suggesting a potential effect of climate change on freshwater phytoplankton.