Abstract
Vertical distribution of phytoplankton in early warming season in the eastern Bering Sea and adjacent sea areas was investigated. In the surface layer which was underthe influence of newly melted sea ice in the shelf water region of the Bering Sea in May, remarkably dense populations of Thalassiosira hyalina and T. nordenskiöldii and relativelylarge populations of Fragilaria and Navicula occupied large part of phytoplankton community.In June, although the Thalassiosira populations sunk into the bottom layer and withered, acertain part of the Fragilaria-Navicula populations was still suspended in subsurface layer.Thus, Fragilaria-Navicula were the leading components of the June community in the shelfregion.
In the Bering Basin region, no dense phytoplankton populations were developed until ashallow thermocline was established. In June when the shallow thermocline developed nearshelf edge, Thalassiosira decipiens burst out. As the shallow thermocline extended from nearshelf to central part of the Basin region with surface warming, the areas of blooming alsoshifted from near shelf to the central part.
