Abstract
Basic research on the occurrence and growth mechanism of cyanobacteria as well as methods to prevent growth have been studied for many years. However, excessive cyanobacteria growth is still occurring frequently in lakes and reservoirs in various places. In recent years, ecological engineering methods have been considered due to their sustainability and energy saving nature. In this study, the hypothesis of whether diatom Nitzschia palea has the growth inhibitory effect on Microcystis aeruginosa (NIES-102) and the water blooms (Microcystis spp. collected from the pond) will be investigated. Moreover, since the wavelength of the optimal light for algae and cyanobacteria to grow varies depending on the species, investigation of the wavelength which suppresses the growth of M. aeruginosa will also be carried out. This will be done in combination with using the competitive nature of N. palea and by using LED irradiation. The results of the empirical investigation showed that in the high nitrogen concentration conditions, the growth of M. aeruginosa was inhibited by the addition of N. palea. However, despite the addition of N. palea and the silicate nutrient to the water blooms collected from the pond, it was not possible to confirm the growth inhibition of the cyanobacteria bloom. In the monoculture, irradiation of blue LED causes N. palea to grow, while M. aeruginosa had suppressed growth. Also, the growth of M. aeruginosa was suppressed by about 78% when compared to the used of monoculture and by adding N. palea under the condition of irradiating yellow LED at 25°C.
