Long-Term Effects of Nanoplastics on Growth, Photosynthesis, and Oxidative Stress in <i>Asterococcus superbus</i>

Nanoplastics (NPs) are emerging environmental pollutants with significant ecological risks, particularly for primary producers such as microalgae. However, most studies have focused on the acute toxicity of NPs, whereas their long-term effects remain poorly understood. This study investigated the long-term impacts of NPs on Asterococcus superbus over a 30-day exposure period, assessing 13 physiological and biochemical parameters related to growth, morphology, photosynthetic activity, and oxidative stress. Results demonstrated that NP exposure led to increased cell density, reduced cell size, and decreased cell complexity, accompanied by oxidative stress. Notably, photosynthetic efficiency was significantly inhibited during the early exposure phase. However, with prolonged exposure, microalgae exhibited physiological self-regulation, partially mitigating NP-induced stress and maintaining functional stability in their photosynthetic apparatus. This study provides critical insights into the resilience of microalgae under NP stress and highlights the need for further research on the ecological implications of chronic NP exposure in aquatic systems.