抄録
Ogouchi reservoir has a problem of the water quality deterioration accompanied with growth of Microcystis and Anabaena. Water samples from the diffusion of public sewerage system for the different water use on rivers were experimented about the blue-green algae growth on Ogouchi reservoir. Microcystis and Anabaena from the sample water of the fishpond has more proliferated than the sample water of river water with treated wastewater. In 2005, Microcystis and Anabaena, together with Oscillatoria of blue green algae, were first observed in Ogouchi reservoir; nevertheless, nitrogen and phosphorus outflow loads and volume of water to Ogouchi reservoir were almost same. While the Oscillatoria are actively growing in the Lake Kasumigaura, Microcystis cannot in there up to now. Similar phenomenon on the selectivity of growth about blue-green algae is confirmed at Ogouchi reservoir. As the results the absence of iron influenced plays a key role about decrease of Microcystis in Lake Kasumigaura. Therefore, the influence of iron in Ogouchi reservoir should also investigates for the future works.
