Effect of Zinc on Basic Physiological Parameters of the Diatom Microalgae Thalassiosira Weissflogii and Assessment of its Toxicoresistance

• Ekaterina Solomonova ^[1] ; Natalia Shoman ^[1] ; Arkady Akimov ^[1] ; Olga Rylkova ^[1] ; Yakov Meger ^[2]
  1. [1] A.O. Kovalevsky Institute of Biology of the Southern Seas

     A.O. Kovalevsky Institute of Biology of the Southern Seas

     Ucrania

     
  2. [2] Sevastopol State University
• Localización: Thalassas: An international journal of marine sciences, ISSN 0212-5919, Vol. 42, Nº. 1, 2026
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • The problem of environmental pollution by heavy metals is global in nature. Although zinc (Zn) is an essential trace element involved in the functioning of more than 300 enzymes, protein synthesis, and regulation of plant growth, its excessive presence in the aquatic environment has toxic effects on hydrobionts. This study investigated the impact of Zn²⁺ at concentrations of 0.1–1.2 mg·L⁻¹ on the diatom microalgae Thalassiosira weissflogii — a promising subject for biomonitoring due to its high sensitivity to pollutants, wide distribution in marine ecosystems, and well-studied physiology. It was established that the toxic effect of zinc is manifested in dose-dependent inhibition of cell growth, suppression of photosynthetic activity (a 40–60% reduction in photosystem II efficiency), and structural changes in cells. In the concentration range of 0.1–0.4 mg·L⁻¹, the population maintained viability, likely due to the activation of defense mechanisms, including the synthesis of metallothioneins and antioxidant enzymes. At concentrations of 0.4–0.7 mg·L⁻¹, most cells exhibited signs of apoptosis: disruption of organelle integrity, chromatin condensation, mitochondrial swelling, and nuclear fragmentation. An important finding is the demonstration of the algae’s ability to fully recover photosynthetic activity and proliferation after transfer from a medium with a sublethal Zn²⁺ concentration (0.4 mg·L⁻¹) to a clean nutrient medium. The obtained data confirm the potential of T. weissflogii as a sensitive bioindicator for assessing both acute and chronic effects of heavy metals, as well as for monitoring the recovery of aquatic ecosystems