Nutrient uptake kinetics, physiology and toxicity of the harmful dinoflagellata Alexandrium tamarense in response to nitrogen supply mode

人为富集氮（N）是甲藻水华的刺激因素之一。氮源并不总是持续地供应给海岸生态系统，而是以脉冲的方式供应。当浮游植物暴露于不同的氮物种，包括混合氮源或不同的氮供应模式，一些生理变化，包括吸收动力学可以预测发生在电话。研究了不同氮源、氮浓度和氮供应方式对塔玛亚历山大藻养分吸收动力学参数和生理特性的影响。不同氮源和两种供氮方式下的细胞碳（C）吸收模式不同。这表明，有机产品如脂质的合成的C需求可能取决于所利用的N。两种供氮方式下的细胞吸氮量呈现相反的趋势。这可能是由于氮素在不同氮素代谢途径和氮素同化过程中的差异所致 ...更多信息 喷烟塔玛亚历山大草能够很容易地采取了三种主要形式的N源供应，无论供应的类型。在一般情况下，铵诱导最高的细胞氮吸收率，其次是硝酸盐，然后尿素。本研究表明，亚历山大藻细胞在突然暴露时具有向不同N源转换的能力。在混合N条件下，呼梯可以同时占用两种N物种。当铵态氮与硝态氮（或铵态氮与尿素）以相同浓度供应时，铵态氮主要被吸收和同化。尿素诱导较高的C：N吸收比相比，硝酸盐和铵生长的细胞。C：N吸收比的变化表明C和N代谢之间的主要相互作用。这种相互作用可能使塔玛藻在不同的N环境下保持高生长。因此，在沿海环境中的N供应的形式可能在控制有毒甲藻的营养吸收，从而有助于甲藻的水华潜力发挥重要作用。快速同时吸收不同种类氮的能力可能是一个重要的机制，可以让A。在氮源复杂的海洋环境中，tamarense能够增殖并形成水华。少

Anthropogenic enrichment in the form of nitrogen (N) is one of the stimuli for the dinoflagellate blooms. N sources are not always supplied to the coastal ecosystem continuously, but also in pulses. When phytoplankton is exposed to different N species including mixed N sources or different N supply mode, some physiological changes including uptake kinetics can be predicted to occur in the calls. In this study, the dints of N sources, concentrations and supply modes on the nutrient uptake kinetic parameters and physiological properties of Alexandrium tamarense were examined. The cellular carbon (C) uptake exhibited different patterns among N sources and also between the two supply modes. This suggests that the C requirement for the syntheses of organic products such as lipid might be dependent on the N utilized. The cellular N uptake was observed to display opposite trend among the two supply modes. This could be due to the difference in metabolic pathways and assimilation of N among N … More spumes. Alexandrium tamarense was able to take up readily the three major forms of N sources supplied, regardless of the type of supply. In general, ammonium induced highest cellular N uptake rates, followed by nitrate and then urea. The present study showed that Alexandrium cells have the capability to switch to different N source upon sudden exposure. In mixed N condition, calls could take up two N species simultaneously. When ammonium plus nitrate (or ammonium plus urea) were supplied in equal concentrations, ammonium was mostly taken up and assimilated. Urea induced higher C: N uptake ratio when compared to those of nitrate and ammonium grown cells. Variability in the C: N uptake ratio indicates major interactions between C and N metabolisms. This interaction may allow A tamarense to maintain high growth under different N environments. Therefore, the form of N supply in coastal environments could play an important role in controlling the nutrient uptake of toxic dinoflagellate and thus contribute to the bloom potential of dinoflagellates. The ability to take up different species of N rapidly and also simultaneously would be an important mechanism that may allow A. tamarense to proliferate and form blooms in marine environments with complex N sources. Less