孔石莼和重金属（铜与镉）对海水无机碳体系影响的模拟研究

通过室内实验模拟并应用海洋生态系统动力学模型,研究了孔石莼和重金属(铜与镉)共同作用下,海水二氧化碳体系及海洋碳源汇强度的变化过程.结果表明,二氧化碳体系各组分含量随时间的变化幅度(Δ)和趋势与重金属种类和添加浓度有关.与对照相比,低浓度(0.1μmol·L^-1和1μmol·L^-1)的铜、镉添加组中,DIC、HCO₃^-和pCO₂均随时间的延长呈下降趋势(p=0.01).而当铜、镉浓度大于“转折浓度”后,t=7时DIC、HCO₃^-和p_CO2均要大于初始值,其增幅随着重金属浓度的增加而增大.对于Δ由负值过渡到正值所对应的“转折浓度”,铜添加组要明显低于镉添加组.这与孔石莼对不同种类重金属的耐受程度不同有关.此外,当重金属浓度不同时,箱中的碳源汇格局亦随时间做不同的变化.当重金属浓度较低时,箱内水体表现为CO₂的汇,并且随着时间推移,可能过渡成为大气CO₂的源;高浓度重金属的影响下,箱内水体表现为CO₂的源,且随重金属浓度的增大,其向大气释放CO2的量也增加.

Effects of heavy metal (copper and cadmium) coupled with Ulca pertusa on marine inorganic carbon system in simulated experiments.

Simulated experiments coupled with ocean biota dynamics were performed in laboratory. In these experiments, effects of heavy metal (copper and cadmium) coupled with Ulca pertusa on marine inorganic carbon system and CO2 fluxes were investigated. The results indicated that concentration changes (delta) of components in carbon dioxide system with time scale were correlated with the concentrations and kinds of heavy metal. In copper groups and cadmium groups (0.1 micromol x L(-1) and 1 micromol x L(-1)), DIC HCO3- and PCO2 significantly decreased comparing to the control experiment data( p = 0.01). However, when the heavy metal infusions were higher than the "critical concentration", the above mentioned parameters increased with time scale and their increments followed the uptrend with increasing heavy metal concentrations. The "critical concentration" in copper groups was much lower than that in cadmium groups, which attributed to the tolerance diversity of Ulca pertusa to copper and cadmium. Furthermore, CO2 fluxes under the influences of heavy metal were also regularly changed with time. Sea waters with low infusions of heavy metal represented as sinks to the atmosphere CO2. These sinks would probably convert into CO2 sources after a period of time. Sea waters with comparatively high amount of heavy metal were always to be CO2 sources, and their release fluxes of CO2 augmented along with the increasing infusions of heavy metal.