Program

Nitrogen  nutrients and nickel（Ni）are ubiquitous in aquatic environments, which are important for primary production of ocean ecosystem. This study examined the interaction of nitrogen nutrients (specifically urea and nitrate) and Ni on chlorophyll (Chl a) concentration and photosynthesis parameters values of Prorocentrum donghaiense and Skeletonema costatum. The data presented here indicate that low concentration of Ni (10 μg·L-1~100μg·L-1 for P. donghaiense and 10 μg·L-1~1 mg·L-1 for S. costatum, respectively) can enhance both Chl a concentration and photosynthesis parameters values when grown in urea culture. Despite this increase there was also an observed depression in both species tested when incubated in high concentration of Ni (1 mg·L-1~100mg·L-1 for P. donghaiense and 10mg·L-1~100 mg·L-1 for S. costatum, respectively) regardless of incubating in urea or nitrate. Additionally, EC50 values of Chl a and Fv/Fm for Ni. These observations indicated that the Ni tolerance was higher in P. donghaiense as compared to S. costatum. The Ni tolerance of P. donghaiense incubated in urea was higher than that incubating in nitrate. The same phenomenon was not observed in S. costatum. Thus, urea input could impact Ni bioavailability and toxicity, and then affect the biodynamics thereafter.