Study On Inhibitory Effects Of Gracilaria Lemaneiformis On The Three Red Tide Microalgae

The inhibitory effects of Gracilaria lemaneiformis on the three red tide microalgae, C. curvisetus, S. trochoidea and S. costatum were studied in the co-culturing system with a series of indoor experiments. The results clearly show that G. lemaneiformis has inhibitory effects on the growth of three microalgae. Increase in the initial biomass of G. lemameiformis decrease the maximum cell densities of C. curvisetus, S. costatum and S. trochoidea.Nutfient and illumination competitions between G. lemameiformis and the three microalgae were noticed. G. lemameiformis shows a competition advantage over the microalgae, while the three microalgae have effects of nutrient competition on growth of G. lemaneiformi. S. trochoidea shows the highest ability of competition with G. lemaneiformi, but C. curvisetus appears the lowest. The weak illumination favors the growth of seaweed. The inhibitory effects of seaweed on three microalgae decrease under the strong illumination. In addition, the aquaculture extracts of G. lemaneiformis has inhibitory effects on the growth of the red tide microalgae.