CO_2加富对颗石藻Emiliania huxleyi生长及钙化作用的影响

Effects of elevated CO_2 concentration on growth and calcification of the coccolithes Emiliania huxleyi

在3个不同的CO2气体浓度(380×10-6、2 000×10-6和10 000×10-6)条件下培养颗石藻Emiliania huxleyi,观察并测定了培养体系的碳酸盐系统参数以及藻细胞的生长与钙化的各参数,比较研究了不同浓度的CO2加富对颗石藻培养的影响。结果表明,380×10-6组(参照组)的pH稳定在8.2左右,而2 000×10-6组降至7.7,10 000×10-6组则低至7.1。与参照组相比,2 000×10-6组的DIC浓度无明显升高,大致为1 900μmol/L,而10 000×10-6组则明显高于前两组,CO2加富对TA浓度变化的影响不显著。380×10-6、2 000×10-6和10 000×10-6三组的平均比生长速率分别为0.27 d-1、0.31 d-1和0.13 d-1,2 000×10-6组的细胞生长最快,而10 000×10-6组最慢,基本处于停滞状态。380×10-6组细胞表面有少数颗石粒,2 000×10-6组的藻细胞生物量和钙化作用显著提高,细胞表面的颗石粒数量较多,而10 000×10-6组的钙化则受到抑制,没有颗石粒。三组的细胞无机与有机成分比分别为0.39∶1、0.84∶1、0.2∶1。

Ecological experiments were conducted to culture the coccolithes Emiliania huxleyi containing three different elevated concentration of carbon dioxide（CO2：380×10-6,2 000×10-6 and 10 000×10-6）.The parameters about the growth and calcification of the cells,and the carbonate parameters of seawater were analyzed during the exposure.A comparative study on the effects of different elevated CO2 concentration on growth and calcification of E.huxleyi was conducted,and the results showed that the pH value in the 380×10-6 group（the reference group） was about 8.2,the 2 000×10-6 group reduced to be 7.7,the 10 000×10-6 group was 7.1.The DIC concentration in the 2 000×10-6 group had no obvious change in comparison with the reference group,was about 1 900 μmol/L,and that the 10 000×10-6 group was higher than the other two groups.But the elevated CO2 had almost no effect on the TA concentration.The average specific growth rates in the three groups were 0.27 d-1,0.31 d-1 and 0.13 d-1,respectively,indicating that,the cells in the 2 000×10-6 group grew the most quickly,and the 10 000×10-6 group was at a standstill.The cell surface in the 380×10-6 group had few coccolith.The biomass and calcification in the 2 000×10-6 group increased obviously,as well as the coccolith.But the calcification in the 10 000 ×10-6 group was inhibited,the surface had no coccolith.The ratio of inorganic and organic components in the three groups were 0.39∶ 1,0.84∶ 1,0.2∶ 1,respectively.