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Interaction effects of oxytetracycline and copper at different ratios on marine microalgae Isochrysis galbana
- Wu, Changlu, He, Chiquan
- Chemosphere 2019 v.225 pp. 775-784
- Isochrysis galbana, absorption, adsorption, biosynthesis, chlorophyll, copper, magnesium, malondialdehyde, microalgae, oxytetracycline, reactive oxygen species
- Contamination with both oxytetracycline (OTC) and Cu is prevalent in water. OTC can chelate with Cu to form OTC + Cu composites. Through the study of the effects of the interaction of OTC and Cu on the algae Isochrysis galbana at multiple coordination ratios, it was found that the OTC + Cu complex was antagonistic to algae growth after 24 h of exposure but was synergistic in treatment (T) 3 and T4 after 48 and 72 h. Compared with OTC alone, the addition of Cu addition significantly inhibited the biosynthesis of chlorophyll a, but the ratio (R) in the OTC + Cu and OTC treatments gradually increased from T1 to T4. The addition of Cu also led to a significant increase in malondialdehyde and reactive oxygen species, but R gradually decreased and increased, respectively, from T1 to T4. The accumulation of OTC in algae was considerably promoted by the addition of Cu, with R increasing 1.5 in T2 to 2.6 in T4; moreover, the residue of OTC in water was reduced in the presence of algae. OTC alone dramatically inhibited the absorption of Cu by algae, while in the presence of OTC + Cu, only the two high-OTC treatments showed a significant decrease in Cu absorption. In addition, the absorption of Mg was markedly inhibited in all OTC treatments and the adsorption of K in the high-OTC treatment, but these inhibitory effects were alleviated in the OTC + Cu treatment. These results indicated that the effects of the OTC + Cu complex on algae were different from the effects of OTC and Cu alone.