title: Effects of Antibiotics on the Growth and Physiology of Chlorophytes, Cyanobacteria, and a Diatom.
abstract: The occurrence of antibiotics in surface waters has been reported worldwide with concentrations ranging from ng L-1to low µg L-1levels. During environmental risk assessments, effects of antibiotics on algal species are assessed using standard test protocols (e.g., the OECD 201 guideline), where the cell number endpoint is used as a surrogate for growth. However, the use of photosynthetic related endpoints, such as oxygen evolution rate, and the assessment of effects on algal pigments could help to inform our understanding of the impacts of antibiotics on algal species. This study explored the effects of three major usage antibiotics (tylosin, lincomycin, and trimethoprim) on the growth and physiology of two chlorophytes (Desmodesmus subspicatus and Pseudokirchneriella subcapitata), a cyanobacteria (Anabaena flos-aquae), and a diatom (Navicula pelliculosa) using a battery of parameters, including cell density, oxygen evolution rate, total chlorophyll content, carotenoids, and the irradiance-photosynthesis relationship. The results indicated that photosynthesis of chlorophytes was a more sensitive endpoint than growth (i.e., EC50derived based on the effects of tylosin on the growth of D. subspicatus was 38.27 µmol L-1compared with an EC50of 17.6 µmol L-1based on photosynthetic rate), but the situation was reversed when testing cyanobacteria and the diatom (i.e., EC50derived based on the effects of tylosin on the growth of A. flos-aquae was 0.06 µmol L-1; EC500.33 µmol L-1based on photosynthetic rate). The pigment contents of algal cells were affected by the three antibiotics for D. subspicatus. However, in some cases, pigment content was stimulated for P. subcapitata, N. pelliculosa, and A. flos-aquae. The light utilization efficiency of chlorophytes and diatom was decreased markedly in the presence of antibiotics. The results demonstrated that the integration of these additional endpoints into existing standardised protocols could provide useful insights into the impacts of antibiotics on algal species.
authors: Environment Department, University of York, Wentworth Way, Heslington, York, YO10 5NG, UK.
authors: Jiahua
authors: J
authors: Guo
authors: Environment Department, University of York, Wentworth Way, Heslington, York, YO10 5NG, UK.
authors: Katherine
authors: K
authors: Selby
authors: Environment Department, University of York, Wentworth Way, Heslington, York, YO10 5NG, UK. alistair.boxall@york.ac.uk.
authors: Alistair B A
authors: AB
authors: Boxall
mesh_terms: D000900:Anti-Bacterial Agents / Q000633:toxicity*; D000460:Chlorophyta / Q000187:drug effects* / Q000502:physiology; D000458:Cyanobacteria / Q000187:drug effects* / Q000502:physiology; D017377:Diatoms / Q000187:drug effects* / Q000502:physiology; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000900:Anti-Bacterial Agents; D014874:Water Pollutants, Chemical