TY - JOUR A1 - Grzesiuk, Malgorzata A1 - Spijkerman, Elly A1 - Lachmann, Sabrina C. A1 - Wacker, Alexander T1 - Environmental concentrations of pharmaceuticals directly affect phytoplankton and effects propagate through trophic interactions JF - Ecotoxicology and Environmental Safety N2 - Pharmaceuticals are found in freshwater ecosystems where even low concentrations in the range of ng L−1 may affect aquatic organisms. In the current study, we investigated the effects of chronic exposure to three pharmaceuticals on two microalgae, a potential modulation of the effects by additional inorganic phosphorus (Pi) limitation, and a potential propagation of the pharmaceuticals’ effect across a trophic interaction. The latter considers that pharmaceuticals are bioaccumulated by algae, potentially metabolized into more (or less) toxic derivates and consequently consumed by zooplankton. We cultured Acutodesmus obliquus and Nannochloropsis limnetica in Pi-replete and Pi-limited medium contaminated with one of three commonly human used pharmaceuticals: fluoxetine, ibuprofen, and propranolol. Secondly, we tested to what extent first level consumers (Daphnia magna) were affected when fed with pharmaceutical-grown algae. Chronic exposure, covering 30 generations, led to (i) decreased cell numbers of A. obliquus in the presence of fluoxetine (under Pi-replete conditions) (ii) increased carotenoid to chlorophyll ratios in N. limnetica (under Pi-limited conditions), and (iii) increased photosynthetic yields in A. obliquus (in both Pi-conditions). In addition, ibuprofen affected both algae and their consumer: Feeding ibuprofen-contaminated algae to Pi-stressed D. magna improved their survival. We demonstrate, that even very low concentrations of pharmaceuticals present in freshwater ecosystems can significantly affect aquatic organisms when chronically exposed. Our study indicates that pharmaceutical effects can cross trophic levels and travel up the food chain. KW - Freshwater microalgae KW - Cellular phosphorus KW - Daphnia KW - Human used-drugs KW - Chronic exposure KW - Environmental risk KW - Fatty acids Y1 - 2018 U6 - https://doi.org/10.1016/j.ecoenv.2018.03.019 SN - 0147-6513 SN - 1090-2414 VL - 156 SP - 271 EP - 278 PB - Elsevier CY - San Diego ER - TY - JOUR A1 - Spijkerman, Elly A1 - Behrend, Hella A1 - Fach, Bettina A1 - Gaedke, Ursula T1 - Decreased phosphorus incorporation explains the negative effect of high iron concentrations in the green microalga Chlamydomonas acidophila JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - The green microalga Chlamydomonas acidophila is an important primary producer in very acidic lakes (pH 2.0-3.5), characterized by high concentrations of ferric iron (up to 1 g total Fe L-1) and low rates of primary production. It was previously suggested that these high iron concentrations result in high iron accumulation and inhibit photosynthesis in C. acidophila. To test this, the alga was grown in sterilized lake water and in medium with varying total iron concentrations under limiting and sufficient inorganic phosphorus (Pi) supply, because Pi is an important growth limiting nutrient in acidic waters. Photosynthesis and growth of C. acidophila as measured over 5 days were largely unaffected by high total iron concentrations and only decreased if free ionic Fe3+ concentrations exceeded 100 mg Fe3+ L-1. Although C. acidophila was relatively rich in iron (up to 5 mmol Fe: mol C), we found no evidence of iron toxicity. In contrast, a concentration of 260 mg total Fe L-1 (i.e. 15 mg free ionic Fe3+ L-1), which is common in many acidic lakes, reduced Pi-incorporation by 50% and will result in Pi-limited photosynthesis. The resulting Pi-limitation present at high iron and Pi concentrations was illustrated by elevated maximum Pi-uptake rates. No direct toxic effects of high iron were found, but unfavourable chemical Pi-speciation reduced growth of the acidophile alga. KW - Chlamydomonas KW - Ecotoxicology KW - Extreme environment KW - Iron toxicity KW - Phosphate limitation KW - Phytoplankton Y1 - 2018 U6 - https://doi.org/10.1016/j.scitotenv.2018.01.188 SN - 0048-9697 SN - 1879-1026 VL - 626 SP - 1342 EP - 1349 PB - Elsevier CY - Amsterdam ER -