环境因子对金藻生长和噬藻速率的影响

在微囊藻的大量培养过程中分离到一株能够快速吞噬微囊藻的鞭毛虫-金藻Poterioochromonas sp.,其具有混和营养的特点。研究以人工培养的铜绿微囊藻(Microcystis aeruginosa FACHB469)为饵料,研究了起始饵料浓度、光强、温度和pH等环境因子对Poterioochromonas sp.生长和吞噬饵料速率的影响。结果显示:当无饵料时,金藻的自养生长与光强和温度相关,而与pH无相关性。喂食饵料能显著促进金藻的生长,其吞噬速率和生长速率与起始饵料浓度相关性强,可分别用Michaelis-Menten方程和Monod方程拟合。提供相同量的饵料时,金藻的生长与光强相关性显著,而与温度和pH的相关性不显著;其吞噬速率与pH呈现负相关关系,而与光强和温度相关性不显著。除了在不同pH下的生长外,混合营养时金藻的生长速率与吞噬速率之间存在显著的正相关关系。实验表明适于Poterioochromonas sp.生存并吞噬微囊藻的环境条件较广,这也是进一步探索利用Poterioochromonas sp.控制微囊藻水华的前提。  

EFFECTS OF ENVIRONMENTAL FACTORS ON THE GROWTH AND INGESTION CHARACTERISTICS OF CHRYSOPHYCEAN POTERIOOCHROMONAS SP.

A chrysophycean Poterioochromonas sp. with two different flagella, isolated from Microcystis cultures in 2002, can not only photosynthesize with chloroplast, but also efficiently ingest and digest preys, such as Microcystis. In order to investigate the potential role of Poterioochromonas sp. in cyanobacteria bloom control, experiments were carried out to study its growth and ingestion characteristics under different environmental factors in both autotrophic and mixotrophic conditions. The results showed that the growth rate of autotrophic Poterioochromonas sp. was significantly affected by light intensity and temperature except pH. When providing preys, the growth of Poterioochromonas sp. was accelerated significantly. The growth and ingestion rate of Poterioochromonas sp. increased hyperbolically with prey concentration, and their relationships could be estimated respectively by the Michaelis-Menten equation and Monod equation. The correlation between the growth of mixotrophic Poterioochromonas sp. and light intensity was significant, while there were no relationships between the growth rate and temperature and pH. PH had negative effects on the ingestion rate, while the correlations between the ingestion rate and temperature and light intensity were not significant. In a word, this Poterioochromonas has the ability to grow and graze Microcystis in many culture conditions. The present study had also shed light on the possibility of utilizing this organism, together with other agents, for the control of Microcystis bloom.