Cu和Pb对赤潮异弯藻(Heterosigma akashiwo)生长的影响

以添加了不同浓度的CuSO_4和Pb(NO_3)_2混合液的f/2培养基培养赤潮异弯藻,通过分析藻的最大生长密度、生长周期及比生长率这3个参数与Cu和Pb之间的相关关系,讨论2种重金属对赤潮异弯藻生长的影响以及2种重金属之间的互作效应。结果表明,Cu为0～0.02 mg·L~(-1)或Pb为0～0.32 mg·L~(-1)时,对赤潮异弯藻生长有促进作用;当Pb浓度不同的条件下,Cu浓度达到0.5～2.5 mg·L~(-1)时,赤潮异弯藻生长受到明显抑制,甚至无法生长;在Cu浓度不同的条件下,Pb在1～9 mg·L~(-1)范围内,随着浓度的增加,对赤潮异弯藻生长抑制作用逐步增强。在Cu浓度为0～2.5 mg·L~(-1)或Pb浓度为1～9 mg·L~(-1)及两者互作条件下,赤潮异弯藻最大生长密度和生长周期都受到显著影响(P0.01)。另外,Cu和Pb对赤潮异弯藻比生长率无显著影响,两者相互作用不明显。结合湛江海域已报道的这2种重金属实际含量,进一步评估了海区中重金属的潜在生态效应。

Effects of Cu and Pb on the Growth of Alga, Heterosigma akashiwo

The objective of this work was to identify the effects of two heavy metals (Cu and Pb) on the growth of Heterosigma akashiwo and the interaction effects between each other. Correlations between the maximum algae density, sustained growth time, the specific growth rate of algae and Cu or Pb treatments were studied by culturing Heterosigma akashiwo in f/2 medium supplemented with CuSO₄ and Pb(NO₃)₂ in different concentrations. The results indicated that the alga was promoted when either Cu was in 0-0.02 mg L^-1 or Pb was in 0-0.32 mg L^-1. Regardless of the concentration of Pb, the growth of Heterosigma akashiwo was significantly inhibited, or even unable to grow when the Cu concentration reached 0.5-2.5 mg L^-1. Regardless of the concentration of Cu, the inhibitory growth effect of the alga was strengthened gradually with Pb concentration increased between 1 and 9 mg L^-1. Cu or Pb or both of them had extremely significant effects on the maximum density and sustained growth time of algae when Cu concentration was 0-0.5 mg L^-1 and Pb concentration was 1-9 mg L^-1 (P<0.01). Cu and Pb did not have significant effect on the specific growth rate of Heterosigma akashiwo, and the interaction effect was not obvious either. The potential ecological effects of heavy metals in Zhanjiang Bay were further evaluated based on the actual contents of these two heavy metals reported in Zhanjiang Bay.