The interaction between NH+4-N and ?NO-3-N in nitrogen uptaking by Ulva prolifera
浒苔对NH+4-N与NO-3-N吸收的相互作用

The nitrogen uptake by Ulva prolifera in the forms of NH+4-N and NO-3-N was investigated. With increasing concentrations of the total nitrogen (NH+4-N/NO-3-N= 1), the absorption rate of NH+4-N was increased, but the absorption rate of NO-3-N? was inhibited. With the ratio of NO-3-N / + NH+4-N > 1, the absorption rate of NH+4-N decreased with the increase of the ratio of NO-3-N/NH+4-N. With the ratio of NH+4-N/ NO-3-N > 1, the absorption rate of NH+4-N was significantly higher than that of NO-3-N by U. prolifera. NH+4-N and NO-3-N can both be absorbed by U. prolifera; the species with higher concentrations will be the main N resource. Therefore U. prolifera can quickly uptake the nitrogen in water for blooning. Moreover the absorption rate of NH+4-N of U. prolifera.was significantly higher than that of NO-3-N in the presence of NH+4-N and NO-3-N. Hence, to prevent the Green Tide blooming, it is key to control the importing of NH+4-N.