1Prefectural University of Kumamoto, Tsukide, Kumamoto 862-8502, 2Kumamoto prefectural Fisheries Research Center, Kamiamakusa, Kumamoto 869-3603, 3Saga University, Honjo, Saga 840-8502, Japan
In the Yatsushiro Sea, from June to October 2008, growth dynamics of Chattonella antiqua were investigated by weekly and monthly samplings in relation to nutrients. To test how well the water in the samples supported the growth of C. antiqua, bioassays of growth of a cultured strain of C. antiqua were also conducted. In closed-off sections of the sea, DIN and DIP concentrations increased and then C. antiqua bloomed at the end of August. In the bioassays, C. antiqua growth decreased with the lack of N-, P- or Fe-sources in comparison with the growth in the complete media. However, the addition of N-source promoted the growth although the addition of P- or Fe-sources had almost no effect, in comparison with basic seawater. The present study indicates that C. antiqua growth is limited primarily by N-source, and secondarily by P- and Fe-sources in the Yatsushiro Sea.