抄録
The effects of unchlorinated activated sludge effluent from a municipal sewage treatment plant on the growth of Porphyra yezoensis were inverstgated for different effluent dosages with different degrees of salinity by means of in vitro static culture. To clarify the effect of the effluent on the Porphyra thalli, the length of thalli and the absorbance spectra of living thalli were measured every two days. The number of dead cells in a thallus were counted using a microscope 10 days after the start of the culture, followed by a erythrosine staining. While increasing the effluent dosage to about 5% by volume, the relative length of thalli decreased rapidly and the number of dead cells quickly increased, and they were enhanced with the lower salinity. When the effluent dosages was above 5%, the relative length of thalli and the number of dead cell had a definite value for each degree of salinity. The absorbance spectra (350-750nm) and absorbance ratio (567nm/676nm) of living thalli increased when the effluent dosage and exposure time were increased.
The above mentioned results suggest that the activated sludge effluent of municipal waste-water may have an adverse effect on the growth of Porphyra thalli.
