东海原甲藻对尿素的吸收动力学与利用特性

Uptake kinetics and utilization characteristics of Prorocentrum donghaiense for urea

以中国东海大规模赤潮发生海区的东海原甲藻为实验材料,研究其对尿素的吸收动力学和利用特性.结果发现,东海原甲藻对尿素N的最大吸收速率(3.184/h)高于氨态N(2.800/h);东海原甲藻在以CO(NH2)2为唯一氮源时的最大比生长速率(0.685/d)超过NO3-(0.663/d);虽然东海原甲藻对NO3-和NH4+的亲和力略高于CO(NH2)2,但由于东海原甲藻具备快速吸收和利用尿素的能力,在无机氮含量较低且尿素丰富的近岸水体中具有竞争优势.指出尿素含量的上升可能是引发东海原甲藻赤潮的重要诱因.

A strain of Prorocentrum donghaiense was isolated from large-scale red tide waters of East China Sea. The growth rates and uptake kinetics of this harmful algal bloom species, with urea as the sole N source, were examined in laboratory cultures. The resuhs show that, the maximum uptake rate of P. donghaiense for urea （3. 184/h） is higher than that of ammonium （2. 800/h）, and the maximum growth rate ofP. donghaiense for urea （0. 685/d） is also higher than that of nitrate （0. 663/d）. It implies that P. donghaiense had higher affinities for nitrate and ammonium than urea; however, P. donghaiense shows higher uptake rate and growth rate with suf- ficient urea in the ambient environments. As P. donghaiense possesses an effective capability in uptake and utili- zation for urea, the rise of urea in the coastal waters from anthropogenic sources would be beneficial to the prolif- eration of the harmful species, contributing to increased occurrences of harmful algal blooms （HABs）.