小球藻纯种室内模拟培养初探

实验以小球藻为藻种, 构建室内模拟培养装置, 在选定的一组优化的光照、温度和营养盐浓度条件下,采用间歇培养+连续培养的方式对其进行单种群培养, 模拟藻类生物量积累的过程。将培养期划分为5个阶段, 通过分析各阶段的光合荧光参数以及藻细胞内C、N、P含量, 初探生物量积累过程中藻生理参数的变化特征, 为研究水华的发生、维持和消退提供一定的参考。结果显示: 调整期, 藻生长不受生境光热、营养盐限制, 小球藻光合活性较强; 对数生长期, 藻类开始出现光抑制, 热耗散增加, 胞内N、P含量及N/P值较高; 对数生长期和稳定期, 藻同时受光抑制和营养盐抑制, N和P含量、N/P值均下降; 连续培养期, 营养盐限制得到缓解, 小球藻光合活性开始升高, 且藻细胞对N、P营养物吸收能力增强。监控藻类生物量积累过程中细胞内氮磷下降的拐点和细胞内元素比例变化可为预测水华的消退提供一定的参考依据。

PRELIMINARY RESEARCH ON CULTIVATED SIMULATION OF CHLORELLA UNDER AXENIC CULTURE

The current study explored physiological characteristics of Chlorella cultivated under axenic culture in the designed simulator with a set of optimized parameters, including light intensity, temperature and nutrient concentrations, by mainly measuring intracellular contents of C, N, P and photosynthesis fluorescent parameters. The experiment employed the Batch culture+ Continuous culture cultivated mode to simulate the formation of algal bloom, and the cultivation period was divided into five phases according to the growth curve. Results showed that Chlorella had highly photosynthetic activity, and the growth was not inhibited by light intensity, temperature and nutrient concentration during adjustment phase. While in exponential phase, the growth of Chlorella was inhibited by light intensity, and heat dissipation was enhanced and intracellular contents of C, N and C/N ratio were high. At stable period, Chlorella was simultaneously inhibited by light intensity and nutrient concentration, and intracellular contents of N, P and N/P ration decreased. In continuous culture phase, when nutrient limitation was mitigated, both photosynthetic activity and the nutrient absorption ability of Chlorella were enhanced. This implied that monitoring the turning point of intracellular nutrients and changes in intracellular element ratio provided a reference basis on the study of the formation, persistence and fade of algal bloom.