Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, 920-1192, Japan.
Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, 920-1192, Japan.
Ecotoxicol Environ Saf. 2020 Sep 15;201:110797. doi: 10.1016/j.ecoenv.2020.110797. Epub 2020 Jun 5.
Microalgae play an important role in arsenic (As) bioaccumulation and biogeochemical cycling in marine ecosystems. Marine microalgal growth and As biotransformation processes depend on environmental factors, including salinity, temperature, and nutrient concentrations, and data in this regard are available in the literature. However, research on the integrated effects of environmental factors on marine diatom species remains scarce and unclear. Herein, salinity and temperature are both considered in combination to investigate their influence on As uptake, biotransformation, and photosynthetic efficiency (PE). Two strains of marine diatom species, Asteroplanus karianus and Skeletonema sp., were cultured in an f/2-based nutrient medium. Microalgae were cultured under various temperatures (5.0, 20, and 35 °C) and salinities (1.0‰, 10‰, 25‰, and 40‰) in association with As and phosphate-enriched (1.0 μmol L of As(V) + 10 μmol L of PO) or deficient (20 nmol L of As(V) + 1.0 μmol L of PO) conditions. For both species, maximum growth, As accumulation, biotransformation, and PE were recorded at 10 and 14 day of culture. Microalgal growth, As accumulation, biotransformation, and PE were maximum at 20 °C with salinities of 10‰ and 20‰. Cell shape was also observed to be good at optimal at this temperature (20 °C) and range of salinity (10‰ and 20‰). A conceptual model of integrated effects of environmental factors on growth and As accumulation and biotransformation activities by these marine microalgae has been proposed. This study contributed to the elucidation of the relationship between environmental factors and As biotransformation mechanisms, which may further provide significant insight about As remediation processes.
微藻在海洋生态系统中砷（As）的生物积累和生物地球化学循环中起着重要作用。海洋微藻的生长和 As 生物转化过程取决于环境因素，包括盐度、温度和营养浓度，这方面的数据在文献中已有报道。然而，关于环境因素对海洋硅藻物种的综合影响的研究仍然很少且不清楚。在此，本文综合考虑盐度和温度，研究它们对 As 吸收、生物转化和光合效率（PE）的影响。以 Asteroplanus karianus 和 Skeletonema sp. 两种海洋硅藻为研究对象，在基于 f/2 的营养培养基中进行培养。在含有 As 和磷酸盐（1.0 μmol L 的 As(V) + 10 μmol L 的 PO）富化或缺乏（20 nmol L 的 As(V) + 1.0 μmol L 的 PO）条件下，微藻在不同温度（5.0、20 和 35°C）和盐度（1.0‰、10‰、25‰和 40‰）下进行培养。对于这两个物种，在培养的第 10 天和第 14 天记录到最大生长、As 积累、生物转化和 PE。微藻的生长、As 积累、生物转化和 PE 在盐度为 10‰和 20‰、温度为 20°C 时达到最大值。在这个温度（20°C）和盐度范围（10‰和 20‰）下，细胞形态也观察到最佳。提出了一个综合环境因素对这些海洋微藻生长和 As 积累及生物转化活性影响的概念模型。本研究有助于阐明环境因素与 As 生物转化机制之间的关系，这可能进一步为 As 修复过程提供重要的见解。
