不同无机氮条件下一种硅藻的氮吸收动力学及模型预测分析

针对海水体系中藻类对无机氮源的吸收利用以及氮源之间相互关系,在室内条件下,利用单细胞藻一次性培养的方法,以无机氮源铵态氮(NH+4-N)和硝态氮(NO-3-N)为基础,通过改变氮源的形态及比例,研究了三角褐指藻(Phaeodactylum tricornutum)的生长动力学和氮吸收动力学特征,并通过构建动力学模型对该特征进行拟合。结果表明,同浓度不同形态的无机氮源培养中,三角褐指藻生长无显著差异(P0.05)。分别以NH+4-N和NO-3-N作为唯一氮源时,三角褐指藻能够快速对氮源吸收利用,而两种氮源同时存在时,藻类优先利用NH+4-N,NO-3-N的吸收则受到一定的抑制。同时,所构建的模型较好地预测了藻类的生长动力学和氮吸收动力学趋势。

Nitrogen uptake kinetics of a diatom and model prediction analysis in different inorganic nitrogen conditions

To investigate the utilization of inorganic nitrogen in the water by marine phytoplankton and the relationship between nitrogen sources, the growth curve and the nitrogen (ammonium and nitrate) uptake characteristics of Phaeodactylum tricornutum under different nitrogen culture conditions were measured in the laboratory. Moreover, a kinetic model was developed to predict these nitrogen uptake processes. The results showed that there was no significant difference in the growth of P. tricornutum (P>0.05) when reared in the same concentration but different forms of inorganic nitrogen cultures. Moreover, either of the two nitrogen forms could be taken up rapidly by Phaeodactylum tricornutum when they were present as the sole nitrogen form, but in mixed nitrogen cultures, nitrate uptake was clearly inhibited in the presence of ammonium. Additionally, the refined kinetic model can accurately predict the nitrogen uptake process in the tests.