*Kotaro Hirose¹, Hanna Nilsson^3,2, Karin Rengefors³, Olof Berglund³, Filipsson F. Helena² (1.Faculty of Science & Engineering, Waseda University, 2.Dept. of Geology, Lund University, Lund, Sweden, 3.Dept. of Biology, Lund University, Lund, Sweden)