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针对2012年在福建沿海致鲍鱼大量死亡、造成了巨大经济损失的米氏凯伦藻赤潮,为验证鲍鱼短时间内大量死亡的原因是否来源于米氏凯伦藻自身的毒性效应,本文初步研究了不同环境条件下,分离自赤潮现场的一株米氏凯伦藻(Karenia mikimotoi)对皱纹盘鲍(Haliotis discus hannai)的急性毒性效应。实验过程中,监测了曝气与非曝气条件下,环境因素中氨氮(TAN)、p H、DO的变化。研究发现,曝气条件下,实验体系中DO的变动范围为7.3~7.8 mg/L,p H的变动范围为7.5~8.2,TAN浓度的变动范围为0.0035~0.084 mg/L(能维持贝类正常生存),此时米氏凯伦藻趋近于赤潮现场藻细胞数量时(3×10~7/L),鲍鱼48 h死亡率为33.3%,96 h内死亡率达100%,说明此时鲍鱼的急剧死亡是由米氏凯伦藻本身的毒性效应引起的。在非曝气条件下,DO由7.1 mg/L降低至1.8 mg/L,实验体系中p H的变动范围为7.2~8.1,TAN的变动范围为0.007~0.051 mg/L,此时米氏凯伦藻藻细胞数量为3×10~7/L时,鲍鱼16 h内死亡率达100%,说明低氧的环境条件可以导致赤潮对鲍鱼的毒性效应加剧。由此可以推测,赤潮发生时皱纹盘鲍短时间内的大量死亡与米氏凯伦藻本身的毒性效应有关,而低氧等环境条件可以导致毒性效应加剧。
In order to verify whether the large number of deaths of abalone in a short period of time caused by the death of abalone in Fujian coastal area resulted in huge economic losses from 2012, The acute toxicity of Karenia mikimotoi separated from Haliotis discus hannai isolated from red tide field under different environmental conditions. During the experiment, the changes of ammonia nitrogen (TAN), p H, DO in the environment were monitored under aeration and non-aeration conditions. The results showed that DO ranged from 7.3 to 7.8 mg / L, p H ranged from 7.5 to 8.2, and TAN ranged from 0.0035 to 0.084 mg / L under aeration Normal survival). At this time, Karenia minkii approached the number of algal cells in the red tide (3 × 10 ~ 7 / L), the mortality rate of abalone at 48 h was 33.3% and the mortality rate reached 100% within 96 h The abrupt death of abalone is caused by the toxic effects of Killer algae itself. Under non-aeration conditions, DO decreased from 7.1 mg / L to 1.8 mg / L, pH of the experimental system ranged from 7.2 to 8.1, and the range of TAN varied from 0.007 to 0.051 mg / L. At this time, When the algae cells were 3 × 10 ~ 7 / L, the mortality rate of abalone within 100 h was 100%, which indicated that the environmental conditions of hypoxia could lead to the aggravation of toxic effects of red tide on abalone. It can be speculated that a large number of deaths of Haliotis discus hannai during the short time of red tide were related to the toxic effects of Kaili algae itself, while the environmental conditions such as hypoxia could lead to the aggravation of toxic effects.