Anthracene phytotoxicity in the freshwater flagellate alga Euglena agilis Carter

Abstract

The freshwater flagellate alga Euglena agilis Carter was exposed to the polycyclic aromatic hydrocarbon (PAH) anthracene for 96 h under optimal photosynthetically active radiation (PAR), and responses of growth, photosynthetic pigment production, and photosynthetic efficiency were assessed. Anthracene reduced the growth rate (μ) and levels of chlorophyll a (Chl a), chlorophyll b (Chl b), and total carotenoids. The growth rate was more sensitive than photosynthetic parameters, with a median effective concentration (EC50) of 4.28 mg L−1. Between 5 and 15 mg L−1, anthracene inhibited the maximum quantum yield (Fv/Fm) of photosystem II (PSII) and the maximum photosynthetic electron transport rate through PSII (rETRmax) with EC50 values of 14.88 and 11.8 mg L−1, respectively. At all anthracene concentrations, intracellular reactive oxygen species (ROS) were elevated, indicating increased oxidative stress. Anthracene presumably reduced the PSII efficiency of photochemical energy regulation and altered the photochemistry through intracellular ROS formation. Acute exposure to PAHs may induce severe physiological changes in phytoplankton cells, which may influence vital ecological processes within the aquatic environments. Additionally, growth and Chl a content may serve as sensitive risk assessment parameters of anthracene toxicity in water management since EC50 values for both overlap with anthracene levels (8.3 mg L−1) permitted by the US Environmental Protection Agency (USEPA).

Assessment of the independent and combined effects of copper and polycyclic aromatic hydrocarbons on gametogenesis and sporophyte development of the kelp Lessonia spicata (Phaeophyceae, Ochrophyta)

“…This would allow discerning the relative proportion of PAHs adsorbed by the cells, on the culture vessel walls, or that volatilize (Christensen and Rorrer 2009). In terms of the negative effects of PAHs on photosynthetic organisms, there is also evidence in higher plants and freshwater microalgae that PAH exposure reduces the growth rate, the chlorophyll a and b levels, and other photosynthetic pigments (e.g., Jajoo et al 2014;Kottuparambil & Park 2019); this is because PAHs inhibit the function of the photosystem II by inducing ROS overproduction (Kottuparambil & Park 2019). Decreased concentrations of photosynthetic pigments and reduction of the efficiency of the photosystem II are induced by exposure to Cu in sensitive brown and green species of algae (e.g., Han et al 2008;Nielsen et al 2003), which is also probably due to their low capacity to mitigate oxidative stress (e.g., Contreras et al 2009;Sáez et al 2015).…”

Microalgae–Bacteria Consortia: A Review on the Degradation of Polycyclic Aromatic Hydrocarbons (PAHs)

“…In a recent study, Euglena agilis was exposed to anthracene that has impaired its photosynthesis, pigmentation, and growth. Its phytotoxic properties are very devastating for aquatic organisms and their associated food chains [47].…”

Aquatic plants and ecotoxicological assessment in freshwater ecosystems: a review

“…As for negative effects of hydrocarbons on aquatic plants, the available studies ( Supplementary Table 3) show that hydrocarbons or their degradation products exhibit toxicity to some microalgae at low concentrations in the mg/L range as genotoxic and mutagenic agents (Eisentraeger et al 2008). The most common responses concern plant growth inhibition, and alteration in photosynthesis and respiration (Marwood et al 1999;Aronsson and Ekelund 2005;Grote et al 2005;Engel et al 2015;Bi et al 2016;Kottuparambil and Park 2019), such as it was also highlighted by the study of El-Dib et al (2001), where the increase in hydrocarbon concentration corresponded to a decrease in plant growth rate and chlorophyll content.…”