摘要
海草床是重要的近岸海洋生态系统之一.痕量元素污染是造成沿海海草床退化的原因之一.鳗草(Zostera marina L.)是温带海域最广泛分布的海草种.本文通过室内模拟实验,以鳗草地上部分伸长长度和最大光量子产量(Fv/Fm)为评价指标,研究了砷、铬、汞、镍、纳米银、锌6种痕量元素胁迫下对鳗草的毒性效应,并确定 6 种痕量元素对鳗草的半效应浓度(EC50).结果表明,6 种元素均对鳗草地上部分伸长长度和Fv/Fm产生了抑制作用,NaAsO2、Na2CrO4·4H2O、HgCl2、AgNPs、NiSO4·6H2O、ZnSO4·7H2O对鳗草的半效应浓度分别为 2.1 mg/L(As:16.0 μmol/L)、89.8 mg/L(Cr:384.6 μmol/L)、0.65 mg/L(Hg:2.2 μmol/L)、8.1 mg/mL(Ag:75.0 μmol/L)、3.0×103 mg/L(Ni:1.1×104 μmol/L)、7.5×104 mg/L(Zn:2.6×105 μmol/L),不同痕量元素对鳗草的毒性大小为Hg>As>AgNPs>Cr>Ni>Zn.本文研究结果将为受损海草床的生态修复及保护管理提供科学依据.
Abstract
Eelgrass has a complete structure consisting of roots,stems,and leaves and completes its entire life cycle in seawater.In this study,the toxic effects of sodium arsenite(NaAsO2),sodium chromate tetrahydrate(Na2CrO4·4H2O),mercury chloride(HgCl2),nano-silver(AgNPs),nickel sulfate hexahydrate(NiSO4·6H2O),and zinc sulfate heptahy-drate(ZnSO4·7H2O)on eelgrass were studied through laboratory simulation experiments.The different concentrations used for inducing stress were NaAsO2(0,1,2,4,and 8 mg/L),Na2CrO4·4H2O(0,20,40,80,and 120 mg/L),HgCl2(0,0.4,0.5,0.6,and 0.7 mg/L),AgNPs(0,1,4,7,and 10 mg/L),NiSO4·6H2O(0,1×103,3×103,5×103,and 10×103 mg/L),and ZnSO4·7H2O(0,0.01×103,0.05×103,0.1×103,0.5×103 mg/L).The partial elongation length and maximum light quantum yield(Fv/Fm)were inhibited by all six elements.The half-effect concentrations of NaAsO2,Na2CrO4·4H2O,HgCl2,AgNPs,NiSO4·6H2O,and ZnSO4·7H2O were 2.1 mg/L(As:16.0 μmol/L)and 89.8 mg/L(Cr:384.6 μmol/L),0.65 mg/L(Hg:2.2 μmol/L),8.1 mg/Ml(Ag:75.0 μmol/L),3.0×103 mg/L(Ni:1.1×104 μmol/L),7.5×104 mg/L(Zn:2.6×105 μmol/L).The toxicity was in the order of Hg>As>AgNPs>Cr>Ni>Zn.
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