典型有机污染物影响下海水二氧化碳体系变化的室内模拟研究

通过室内模拟实验，研究了典型有机污染物［乙醇、丙酮、尿素(ON)和多灭磷(OP)］对海水pH和二氧化碳体系的影响.结果表明，t=7　d时，低浓度的醇和酮（<0.5 mmol·L^-1）促进生物固碳体系生长，相应水体中的pH值升高，而DIC、HCO^-₃和p(CO²)与对照组相比都明显下降（p<0.01）；引起DIC、HCO^-₃及p(CO²)下降幅度最大的醇和酮浓度分别为0.25 mmol·L^-1和0.1 mmol·L^-1. 当醇、酮达到一定浓度后，藻类固碳能力开始下降，甚至分解并转化为无机碳，从而引起DIC、HCO^-₃和p(CO²)含量的升高及pH值的下降.实验设计范围内的ON和OP添加组中，上述二氧化碳体系各组分含量与其初始值相比，均呈现负变化，即对应水体中DIC、HCO^-₃和p(CO²)均在降低.t=7　d时, 4种典型有机污染物影响下的DIC变化幅度(ΔDIC)与相应水体中孔石莼干重变化量(Δm)呈现显著负相关（p<0.01或p<0.05），相关系数分别为：-0.902、 -0.945、 -0.898和-0.918.造成以上差异的原因与生物固碳体系在不同种类不同浓度有机污染作用下对海水二氧化碳利用性不同有关.

Effects of Typical Organic Pollutants on Marine Dioxide Carbon System in Simulated Experiments

The effects of typical organic pollutants (ethanol, acetone, ON, OP)on pH and marine carbon dioxide system were investigated in laboratory simulated experiments. The results indicated that the growth of biological carbon fixed system was promoted by ethanol and acetone of low concentration(<0.5 mmol·L-1) (t=7 d). So pH increased while DIC,HCO-3 and p(CO2) significantly decreased compared to the controls (p<0.01). The concentrations of ethanol and acetone which resulted in the maximum decrease of carbon dioxide parameters were 0.25 mmol·L-1 and 0.1 mmol·L-1, respectively. When the infusion of organic pollutants were higher than the "critical concentration", the carbon dioxide parameters increased and pH decreased compared to the controls with the decrease of carbon fixation strength of alga. As for ON and OP groups, when they were in the range of experimental concentration, decreasing trends of inorganic carbon in sea water were always found. The concentration changes of DIC (ΔDIC) under the press of the four typical organic pollutants were significantly negatively correlated with the changes of dry weight of alga (p<0.01 or p<0.05) and the coefficient parameters were -0.902, -0.945, -0.898 and -0.918, respectively (t=7 d). The main controlling factor to the variation of carbon dioxided system was the adaption of biological carbon fixed system to different concentration and kind of organic pollutants.