Exposure of engineered nanoparticles to Alexandrium tamarense (Dinophyceae): Healthy impacts of nanoparticles via toxin-producing dinoflagellate

摘要

Human activities can enhance the frequency, intensity and occurrence of harmful algal blooms (HABs). Engineered nanoparticles (ENPs), contained in many materials, will inevitably enter coastal waters and thus cause unpredictable impacts on aquatic organisms. However, knowledge of the influence of ENPs on HAB species is still lacking. In this study, we examined the effects of titanium dioxide nanoparticles (_nTiO_2), zinc oxide nanoparticles (_nZnO) and aluminum oxide nanoparticles (_nAl_2O_3) on physiological changes and paralytic shellfish poisoning toxins (PSTs) production of Alexandrium tamarense. We found a dose-dependent decrease in photosynthetic activity of A tamarense under all three ENPs and a significant growth inhibition induced by _nZnO. The largest reactive oxygen species (ROS) production was induced by _nTiO_2, followed by _nZnO and _nAl_2O_3. Moreover, the PSTs production rate increased by 3.9-fold for _nTiO_2 (p < 0.01) and 4.5-fold for _nAl_2O_3 (p < 0.01) at a concentration of 200 mg L~(-1) The major component, C2 was transformed to its epimer C1 and the proportion of decarbamoyl toxins increased under 200 mg L~(-1) of _nZnO and _nAl_2O_3. In addition, the proportion of carbamate toxins increased upon exposure to 2 mg L~(-1) ENPs, while decreased upon exposure to 200 mg L~(-1) ENPs. The changes in PSTs production and composition might be an adaptive response for A. tamarense to overcome the stress of ENPs exposure. This work brings the first evidence that ENP would affect PSTs production and profiles.