Abstract
In this study, we made a spectral sensor which is composed of a photometer and a metalhalide lamp to monitor Microcystis. The photometer is made of nine photodiodes and three interference filters(550, 670, 800nm). Absorbance of some water samples;Microcystis, Spirogyra, Andosol and Magnesium oxide; were measured in laboratory using the sensor. The results show that the absorbance of Microcystis and Spirogyra is similar to the one of land plants. Therefore, concentration of these phytoplanktons will be estimated by difference of absorbance of 800nm and 550nm. Microcystis and Spirogyra are classified using the specific feature of Phycobilin. Phycobilin, which is characteristic pigment of the bluegreen algae, is not contained in Spirogyra but in Microcystis. Since Phycobilin absorbs electromagnetic wave in 500-650nm, the absorbance of 550nm significantly increases with increasing of concentration of Microcystis. As abovementioned results, following steps to measure Microcystis are derived. First, divide phytoplanktons and others by the difference of absorbance of 800nm and 550nm. Second, divide the blue-green algae and other phytoplanktons by the difference of absorbance of 670nm and 550nm.
