Photosynthetic Toxicity of Enrofloxacin on Scenedesmus obliquus in an Aquatic Environment

Abstract

Aquaculture facilities are a potential source of antibiotics in aquatic environments, having adverse effects on the algae species. In this study, the toxicity induced by enrofloxacin (ENR) on the algae Scenedesmus obliquus was evaluated. The uptake of ENR and the change in the growth and photosynthesis of algae were analyzed. At the exposure doses of 10–300 μg/L, the accumulated levels of ENR in algae were 10.61–18.22 μg/g and 12.09–18.34 μg/g after 48 h and 96 h of treatment, respectively. ENR inhibited the growth of algae, with a concentration for 50% effect of 119.74 μg/L, 53.09 μg/L, 64.37 μg/L, and 52.64 μg/L after 24 h, 48 h, 72 h and 96 h of treatment, respectively, indicating the self-protection and repair ability of algae in a short period of time. Furthermore, the chlorophyll contents decreased in all treatment groups, and the photosynthetic system Ⅱ parameters decreased in a dose-dependent manner under ENR stress, suggesting that ENR caused a disorder in the electron transport of the photosynthesis of algae, and the carbon fixation and assimilation processes were thus damaged. These results indicate that ENR poses a considerable risk to aquatic environments, affects the carbon sinks, and even has an adverse effect on human health.

Toxicity, physiological response, and biosorption mechanism of Dunaliella salina to copper, lead, and cadmium

“…Photosynthetic pigments are essential in assessing the photosynthetic capacity of plants or algae and the extent of environmental stress ( Li et al, 2022 ). After exposing to different concentrations of Cu 2+ , Pb 2+ , and Cd 2+ for 72 h, the contents of photosynthetic pigments, including chlorophyll a (Chla), chlorophyll b (Chlb), total chlorophyll (Ct), and carotenoids (Car), in D. salina were enhanced when Cu 2+ concentration was under 10 mg/L, indicating that low dose of copper could trigger the accumulation of photosynthetic pigments, whereas these pigments declined with the increase in Cu 2+ concentration (>10 mg/L), exhibiting a hormesis effect ( Figure 2 ), which was consistent with the inhibitory effect.…”

Effects of Enrofloxacin on the Epiphytic Algal Communities Growing on the Leaf Surface of Vallisneria natans

“…Studies have shown that Scenedesmus is a typical alga with an inducible defense ability, and S. quadricauda can induce the degradation of antibiotics, such as ciprofloxacin and levofloxacin, through biotransformation or biocatalysis by means of decarboxylation and demethylation [ 28 , 29 ], so the relative abundance of S. quadricauda in the ENR concentration of the 200 mg∙L −1 treatment group is relatively high compared with the other treatment groups.…”