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Automated swimming activity monitor for examining temporal patterns of toxicant effects on individual Daphnia magna
Author(s) -
Bahrndorff Simon,
Michaelsen Thomas Yssing,
Jensen Anne,
Marcussen Laurits Faarup,
Nielsen Majken Elley,
Roslev Peter
Publication year - 2016
Publication title -
journal of applied toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.784
H-Index - 87
eISSN - 1099-1263
pISSN - 0260-437X
DOI - 10.1002/jat.3212
Subject(s) - toxicant , daphnia magna , ec50 , toxicity , toxicology , chemistry , ecotoxicology , incubation , abiotic component , environmental chemistry , biology , ecology , biochemistry , in vitro , organic chemistry
Aquatic pollutants are often biologically active at low concentrations and impact on biota in combination with other abiotic stressors. Traditional toxicity tests may not detect these effects, and there is a need for sensitive high‐throughput methods for detecting sublethal effects. We have evaluated an automated infra‐red (IR) light‐based monitor for recording the swimming activity of Daphnia magna to establish temporal patterns of toxicant effects on an individual level. Activity was recorded for 48 h and the sensitivity of the monitor was evaluated by exposing D. magna to the reference chemicals K 2 Cr 2 O 7 at 15, 20 and 25 °C and 2,4‐dichlorophenol at 20 °C. Significant effects ( P < 0.001) of toxicant concentrations, exposure time and incubation temperatures were observed. At 15 °C, the swimming activity remained unchanged for 48 h at sublethal concentrations of K 2 Cr 2 O 7 whereas activity at 20 and 25 °C was more biphasic with decreases in activity occurring after 12–18 h. A similar biphasic pattern was observed after 2,4‐dichlorophenol exposure at 20 °C. EC 50 values for 2,4‐dichlorophenol and K 2 Cr 2 O 7 determined from automated recording of swimming activity showed increasing toxicity with time corresponding to decreases in EC 50 of 0.03–0.07 mg l –1 h –1 . EC 50 values determined after 48 h were comparable or lower than EC 50 values based on visual inspection according to ISO 6341. The results demonstrated that the swimming activity monitor is capable of detecting sublethal behavioural effects that are toxicant and temperature dependent. The method allows EC values to be established at different time points and can serve as a high‐throughput screening tool in toxicity testing. Copyright © 2015 John Wiley & Sons, Ltd.