Biological Effect of Single Wall Carbon Nanotubes on Skeletonema costatum and Prorocentrum donghaiense in Seawaters

Carbon nanotubes (CNTs) have been used in a variety of industrial areas as a kinds of new nanometer materials. Algal growth test was developed to determine the biological effect of single-walled carbon nanotubes (SWNTs) on Skeletonema costatum and Prorocentrum donghaiense. The results showed that SWNTs stimulated the growth of S. costatum within 72 h and 24 h as theirs concentrations were smaller than 0.5 mg/L and 10 mg/L respectively, While the growth of S. costatum was inhibited within 48 h and 96 h as theirs concentrations were higher than 10 mg/L and 0.5mg/L respectively (p＜0.05). The concentrations of chlorophyll were the same as the density of phytoplankton cells. The growth of P. donghaiense was inhibited as SWNTs concentrations were higher than 100 mg/L within 72 h, while SWNTs promoted the growth of P. donghaiense within 48 h after SWNTs were added as their concentrations were smaller than 5 mg/L（p＜0.05). The results of chlorophyll were similar to the density of P. donghaiense cells. The roles of SWNTs on the growth of algae were suggested to be associated with the active of some enzymes and the physical properties, such as agglomeration and shading.