2004 Volume 65 Issue 1 Pages 27-35
In order to elucidate the species composition of phytoplankton and its characterization in brackish Lake Obuchi, located virtually in the center of the Shimokita Peninsula in Aomori Prefecture, observations were made of phytoplankton and water quality from April 2001 to March 2003. Mean cell density of the phytoplankton at the freshwater river estuary and the central point in lake reached 4.3×106 and 5.4×106 cells L-1, respectively. There was no significant difference in density between the stations. Phytoplankton identified in the present study totaled were 97 species, the most dominant of which in this lake were Skeletonema costatum, Cyclotella spp., Melosira juergensii, Nitzschia pungens, Chaetoceros sp. and Prorocentrum minimum. It was clarified that the dominant species of phytoplankton occurring in Lake Obuchi enjoyed optimum conditions for salinity (5 to 30 psu) and water temperature (< 15°C).
