ABSTRACT
Microalgae are the basis of the aquatic food webs. Perturbations of phytoplankton communities as a consequence of the occurrence of toxic compounds can affect both the structure and the function of the whole ecosystem. Nowadays, the wide use of metal (Me-ENPs) and metal oxide (MeO-ENPs) engineered nanoparticles have increased the release of such nanomaterials to the aquatic ecosystems affecting both fresh and seawater phytoplankton species. This chapter summarizes the current knowledge on the intrinsic (e.g. particle size, specific surface area, shape, zeta potential, water solubility, photocatalytic activity, crystallization, purity, redox potential, and coating composition) and extrinsic factors (chemical transformations, agglomeration/aggregation, redox stage, eco-corona formation) that affect the toxicity of Me-ENPs and MeO-ENPs. The mechanisms involved in the internalization of NPs, their toxic effect (e.g. ROS production, ultrastructure changes, cell viability, DNA damage) and to counteract them (e.g. EPS production) are discussed. Finally, general aspects, related to the improvement of ENPs toxicity tests, climate changes effects, and trophic transfer are considered.
