|富营养湖泊中蓝藻水华对枝角类种群和群落结构有显著的影响,但自然条件下群体微囊藻对大型枝角类溞属不同种类的影响仍存在争议.本研究通过两次为期各10 d的模拟实验,利用过滤后的太湖原水模拟群体微囊藻(20~100μm和100~200μm)添加对大型枝角类同形溞(Daphnia similis)种群特征的影响,结果显示两次实验的同形溞均大量存活,不同浓度和颗粒大小的群体微囊藻对其生长和繁殖的影响不同,添加群体微囊藻的同形溞的生长和繁殖显著大于未添加微囊藻的.说明在自然条件下藻毒素对同形溞种群并没有明显的抑制作用,同形溞能够与微囊藻水华共存,其种群特征与微囊藻群体大小组成和生物量有关.
|关键词: 群体微囊藻 藻毒素 同形溞 种群 太湖
|Effects of colonial Microcystis spp. on the growth and reproduction of large-sized cladoceran Daphnia similis in Lake Taihu
DAI Xi1,2, CHEN Feizhou1
1.State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China;2.Graduate University of Chinese Academy of Sciences, Beijing 100049, P. R. China
|Cyanobacterial blooms in eutrophic lakes have significant influence on population and community structures of cladoceran, but the impacts of natural colonial Microcystis spp. on the growth and reproduction of Daphnia remain controversial. Two 10-day experiments were conducted separately to simulate the impacts of the colonial Microcystis spp. (20 100 μm and 100 200 μm) on population characteristics of D. similis, which were cultivated in filtered water from Lake Taihu. The results show that colonial Microcystis spp. has no significantly negative effect on the survivorship of D. similis. The growth rate and reproductive capacity of D. similis differed among different concentrations and sizes of colonial Microcystis spp., which was significantly higher in groups with Microcystis than the control group. Our results indicate that there is no significant inhibition from cellular microcystins on the population of D. similis in natural conditions. D. similis can coexist with Microcystis blooms and its population characteristics are mostly affected by the size composition and biomass of colonial Microcystis spp.
|Key words: Colonial Microcystis spp. microcystins Daphnia similis population Lake Taihu