Abstract
The growth kinetics of blue-green alga Microcystis aeruginosa and diatom Cyclotella sp. under calcium limitation were determined in batch culture experiment at 20℃. The maximum growth rate, μmax, and half saturation constant, Kca, under the calcium limited condition were estimated as 0.51 d-1 and 1.00 mg-Ca/l for M. aeruginosa, while those for Cyclotella sp. were μmax = 0.56 d-1 and Kca = 1.46 mg-Ca/l, respectively. The Kca value for M. aeruginosa was two orders of magnitude greater than 0.002 mg-P/l of Kp which was obtained for phosphorus. The competitive culture experiment was also conducted for the above two species. Though M. aeruginosa dominated at the calcium concentration ranging 1.0 and 10 mg/l, neither M. aeruginosa nor Cyclotella sp. could grow in the calcium of 0.1 mg/l despite significant phosphorus concentration of 1.55 mg/l had been achieved in the batch culture. These results suggested that calcium concentration would also be one of the decisive factors for the growth of M. aeruginosa.
