Fisheries and Aquaculture Sustainability

Functionalized nanoplastics alter physiology and toxin production in Alexandrium pacificum through surface charge effects

L Li, M Hu, S Gul, Y Ma, X Dai, Q Hao, J Zhang, W Huang, Y Wang

Sustainable Horizons 2026 DOI: 10.1016/j.horiz.2025.100171

Abstract

Nanoplastics have emerged as a significant threat to marine ecosystems. Those with functional modifications particularly impact biological processes, as their surface potential governs particle-organism interactions and electron transfer. Here, we evaluated the endpoints related to growth, photosynthesis, antioxidant defence, and paralytic shellfish toxins (PSTs) content in Alexandrium pacificum exposed to 100 nm functionally modified nanoplastics (NP, NP-NH2 and NP-COOH) of 0, 0.1 and 1 mg/L for 21 days. Our findings indicate that: Exposure to 1 mg/L NP increased microalgae growth by 31.4%, while NP-NH2 (1 mg/L) promoted growth throughout the experiment. Significant nanoplastics accumulation occurred on microalgae surfaces. NP (1 mg/L) induced a significant increase in photosynthetic activity. Toxicity of nanoplastics exhibited a concentration-dependent increase that was independent of functional modification, which, together with concentration, significantly interacted to affect cell membrane permeability. In addition, NP-NH2 altered the PSTs composition, increasing C1/C2 levels by 121.2% (1 mg/L) and 159.88% (0.1 mg/L) compared to controls. In summary, NP-NH2 exhibited higher bioavailability than NP-COOH and NP. Our study underscores the critical role of functional groups in mediating the effects of nanoplastics on harmful microalgae physiology, particularly intracellular PSTs dynamics, which may profoundly impact ecosystems through food chain transfer.

Nanoplastic exposure induces exoskeletal misdevelopment in juvenile Tachypleus tridentatus: Compensatory hardening versus molecular suppression

L Jiang, Y Wang, J Fang, K Waiho, W Liu, J Lee, X Ma, M Hu

Marine Pollution Bulletin 2026 DOI: 10.1016/j.marpolbul.2026.119327

Abstract
Microplastic and nanoplastic pollution poses a significant threat to marine ecosystems, yet its impact on the critical physiological processes of endangered marine arthropods remains poorly understood. This study reveals that chronic exposure to polystyrene nanoplastics (1, 10, 100 μg/L) disrupts the exoskeletal sclerotization process in first-instar juveniles of the endangered Chinese horseshoe crab, Tachypleus tridentatus. Our results demonstrate that nanoplastics trigger a compensatory hardening response in the juvenile carapace, which depends on both the exposure dose and duration. This response manifested as a larger and biomechanically stronger shell, with increased maximum load and tensile strength. Despite this enhanced physical strength, we observed a significant suppression of key sclerotization-related genes (E74, Calmodulin, and Carbonic Anhydrase). This gene downregulation suggests that the normal pathways for molting and shell mineralization were being disrupted. Conversely, a significant elevation in N-acetyl-β-D-glucosaminidase (NAG) activity suggested a disrupted balance between exoskeleton degradation and synthesis. In conclusion, nanoplastic exposure causes a profound mismatch between gene expression and phenotypic outcomes in T. tridentatus, forcing a potentially costly compensatory response that may impair their molting success and long-term survival, thereby highlighting a severe ecological risk to this ancient species.