@article{oai:kochi.repo.nii.ac.jp:00006496, author = {Haraguchi, Hiroko and Sekida, Satoko}, issue = {1}, journal = {黒潮圏科学 = Kuroshio Science}, month = {Mar}, note = {application/pdf, Various seaweed and seagrass beds (Moba in Japanese) grow in the coastal waters of Japan. In this presentation we introduce Sargassum beds, which are classified as brown algae. Sargassum species are distributed widely along not only the Japanese coast but also the Philippine and Taiwanese coasts. The occurrence of common species is due to the Kuroshio Current. From the 1970s to the 1990s, species of Sargassum beds in Tosa Bay were changing. That is the temperate Sargassum species declined and were replaced by the tropical Sargassum species. We propose two possible reasons this phenomenon. One reason is that the water temperature rose in Tosa Bay. Specifically, the winter water temperature during the 1990s was much higher than during the 1970s and the 1980s. We discuss how this has enabled the growth of the tropical Sargassum species. With this in mind we conducted culture experiments to compare the growth characteristics between the temperate species and the tropical species in low temperature. The results indicated that the growth rates of the tropical species are significantly higher than those of the temperate species for temperatures of over 14 degrees. This may be one of the causes of the expansion in the distribution of the tropical Sargassum species. Second reason is that barren grounds have increased in area in Tosa Bay. This phenomenon is a serious problem. However when we change the environment, new tropical species may have opportunities to grow instead of existing seaweeds. To understand these phenomena it is important for us to research the ecology and physiology of seaweeds occurring along the Kuroshio Current.}, pages = {41--46}, title = {Recent Changes in the Distribution of Sargassum species in Kochi, Japan}, volume = {2}, year = {2008} }