Influence of CO2 enrichment on the allelopathic effect of Sargassum thunbergii on Skeletonema costatum
CO2加富培养对鼠尾藻克制赤潮异弯藻效果的影响

The allelopathic effect of Sargassum thunbergii on Skeletonema costatum and its response to CO2 enrichment were investigated by an experimental ecology method. Results showed that, under normal conditions, fresh tissue, dry power and aqueous extracts of S. thunbergii resulted in remarkably reductions in cell density of S. costatum (P<0.05). In addition, the fresh tissue, dry power and aqueous extracts of S. thunbergii, which were cultured under CO2 enrichment conditions, led to more significant decreases in cell density of S. costatum (P<0.01). Under normal conditions, the culture media filtrate of S. thunbergii drastically inhibited the growth of S. costatum (P<0.05), while that of S. thunbergii which were cultured under CO2 enrichment conditions did not exhibit significantly inhibitive effect on S. costatum (P>0.05). Therefore, it was speculated that the mediating mechanism of the allelopathic effect might be changed by CO2 enrichment, from the secreted allelopathic substances to direct cell contact.