Abstract:Simulated experiments were performed in laboratory. In these experiments, effects of heavy metal (copper, cadmium, zinc and lead) coupled with Ulca pertusa on marine inorganic carbon system and CO2 fluxes were investigated. The results indicated that concentration changes (Δ) of inorganic carbon system were correlated with the concentrations and kinds of heavy metal (t=7d). In the heavy metal groups of low concentration (<1μmol·L-1), DIC、HCO-3and Pco2 significantly decreased comparing to the control experiment data (P<0.01**). When the infusions of copper and cadmium were higher than the “critical concentration”, the above mentioned parameters increased comparing to the control experiment data and their increments followed the uptrend with increasing heavy metal concentrations. As for zinc and lead, when they were 50μmol·L-1, decreasing trend of inorganic carbon in sea water was still found. Moreover, the results indicated that CO2 sink/source pattern might be controlled by the concentrations and kinds of heavy metal. When the infusions of copper and cadmium were lower than that critical concentration, the corresponding sea waters were presented as sinks to atmospheric CO2. These sinks would probably convert into CO2 sources after the dose of copper and cadmium exceeding the critical concentration and their release fluxes of CO2 augmented along with the increasing infusions of heavy metal. For the groups of zinc and lead, in the range of our experiment dose, the sea waters were always present as atmospheric CO2 sinks. However, when the concentrations of zinc and lead were higher than 15μmol·L-1 and 20μmol·L-1, respectively, their carbon sink strength became less than that of the control experiment (P<0.05*).