Inter-specific competition of Karenia mikimotoi and Platymonas subcordiformis under different level of nutrients

The competitive effects of Karenia mikimotoi and Platymonas subcordiformis under the different level of nutrients were studied.The results show that(1) Under the single-cultured conditions,the K and r value of K.mikimotoi and P.subcordiformis were increased with N,P nutrient concentrations increasing.The P restrictive effect to the growth of K.mikimotoi is more obvious.It is not suitable for the growth of K.mikimotoi whenever the value of N/P is higher or lower,and 24.4 is the best value for the microalgae growth.(2) Under the co-cultured conditions,the growth of K.mikimotoi is inhibited by P.subcordiformis during every level of nutrients(P0.5).In the more abundant nutrient components,all of K.mikimotoi is dead after 7~9 days.However,K.mikimotoi is not completely dead,but its density is only 0.8~3 times than the initial inoculation density in the extreme shortage of nutrient components.