Daphnia Activity Monitoring


A New Multi-cell Exposure System for Continuous Tracking of Daphnia Behavior for Toxicity Assessments


For several years, video tracking systems have been developed to analyze alterations in the swimming behavior
of daphnia to provide early signals of chemical stress. However, these systems have limited testing abilities that do not
allow for a systematic analysis of the robustness of behavioral endpoints. With recent advances in behavior tracking
technology, we were able to develop a new behavioral analysis multi-cell exposure system named “Multi-DaphTrack”
with a high-throughput testing capacity for assessing the behavioral response of Daphnia magna. The insecticide
esfenvalerate was chosen as chemical model and tested on daphnid neonates at several concentrations for 48 h to
(i) evaluate the performance of this new system and (ii) compare the sensitivity of our new multi-cell system with the
standard immobilization assay and the Bbe®
Daphnia Toximeter. Overall, the results demonstrated that our new “MultiDaphTrack” system can detect significant behavioral effects of esfenvalerate at concentrations as low as 0.14 µg/L from
a minimum of 1 h of exposure. Similar rapid behavioral effect trends were observed with the Bbe®
Daphnia Toximeter.
The behavior proved to be more sensitive than the standard immobilization endpoint. Significant behavioral changes
were observed at the esfenvalerate concentrations that occur in contaminated rivers from agricultural areas in Europe
and North America.

Life history and behavior effects of synthetic and natural dyes on Daphnia magna





• Basic Red 51 and Erythrostominone are acutely toxic to Daphnia magna.
• Both dyes induce deleterious consequences at population level for daphnids.
• Basic Red 51 increases the respiration rate of daphnids.
• Erythrostominone toxicity is 100-fold lower in comparison to Basic Red 51.
• After photodegradation, Erythrostominone loses its toxic potential to D. magna.



Azo dyes are the largest class of dyes extensively used by industries despite their mutagenic potential for humans. As such, natural dyes have been reemerging as an important alternative to human safety. However, limited studies have focused on the effect of dyes on the environment, thus their ecotoxicological investigation is imperative. Here, we aimed to evaluate toxic effects induced by the synthetic azo dye Basic Red 51 (BR51) in comparison with natural dye erythrostominone (Ery) in the microcrustacean Daphnia magna, a standard organism used to assess the risk of chemicals to aquatic organisms. The colorless product formed after the photodegradation of Ery (DEry) was also evaluated, addressing an easy and low cost alternative for industrial effluent treatments. The results showed that both dyes are acutely toxic to D. magna. BR51 and Ery reduced the intrinsic rate of D. magnapopulation increase, which generated fewer neonates per brood. BR51 also increased daphnids respiration rates. In contrast, DEry did not alter any of the analyzed parameters. No locomotor changes were observed when daphnids were exposed to sub-lethal concentrations of Ery or BR51. These results indicate that both dyes can induce deleterious consequences for daphnids including population level effects, but the natural dye Ery presents 100-fold lower toxicity in comparison with the azo dye BR51. Also, that photodegradation of Ery is an efficient method to reduce and prevent previously observed toxic effects, suggesting an inexpensive, fast and easy alternative for treatment of effluents containing this natural dye.


Link to the publication : https://www.sciencedirect.com/science/article/pii/S004565351931611X

Multi-parametric analysis of ciprofloxacin toxicity at ecologically relevant levels: Short- and long-term effects on Daphnia magna

Environmental Toxicology and Pharmacology




• Alterations of phase II metabolism were enhanced after ciprofloxacin (CPX) exposure.
• Ciprofloxacin may lead to a neurotoxic effect on Dapnhia magna.
• Fluoroquinolones may cause oxidative stress, promoting cellular damage.
• Swimming behaviour may be compromised by CPX.
• CPX altered energy allocation by parental organisms, producing smaller neonates.


The increased presence of emergent compounds, such as pharmaceuticals drugs, in the aquatic compartment has been acknowledged as an evolving environmental issue whose consequences are not yet fully characterized. Specific classes of pharmaceutical drugs, such as fluoroquinolone antibiotics, can exert toxic effects to non-target species with ecological significance, since these compounds are environmentally stable and persistent, and may interact with some of the key physiologic processes of organisms. Despite such characteristics, knowledge about the effects of these drugs is still scarce, especially to non-target organisms. The present study aimed to evaluate the effects of chronic and acute exposures of the cladoceran Daphnia magna to the fluoroquinolone antibiotic ciprofloxacin. Putative toxic effects were assessed, following acute and chronic exposures to ecologically relevant concentrations of ciprofloxacin, through enzymatic (cholinesterase – ChEs, catalase – CAT, glutathione S-transferases – GSTs) and non-enzymatic (thiobarbituric acid reactive substances – TBARS, glycogen – Gly) biomarkers. In addition, we also determined behavioural (swimming distance – SD) and morphological (body length of the first brood – BL1B) endpoints in animals exposed to this drug. Ciprofloxacin acute exposure resulted in increased CAT and ChEs activities, and inhibited GSTs activity. After chronic exposure, ChEs activity was significantly inhibited, while GSTs activity was significantly enhanced. TBARS levels were only increased at higher concentrations of ciprofloxacin. CAT activity and Gly content did not evidence a clear and significant pattern of variation. SD was slightly inhibited during dark cycles. BL1B presented a significant decrease for animals subjected to an intermediate concentration. Results showed that even ecologically relevant concentrations of ciprofloxacin may cause oxidative stress in individuals of D. magna. The present study showed important data that corroborate the occurrence of significant biochemical alterations in key features of an aquatic organism when exposed to relevant levels of a widely used antibiotic, establishing essential links between environmental exposure to this specific drug and putative toxic challenges that may result in irreversible changes and damages, especially at the individual level. However, changes in the size of neonates suggest that population alterations are likely to occur under real scenarios of chronic contamination by this drug.


Link to the publication :


Phytoremediation processes of domestic and textile effluents: evaluation of the efficacy and toxicological effects in Lemna minor and Daphnia magna

Environmental Science and Pollution Research



Phytoremediation has been proposed as a potential biotechnological strategy to remediate effluents before their release into the environment. The use of common aquatic plant species, such as macrophytes (e.g., Lemna spp.) as a cleanup solution has been proposed decades ago. However, the effectiveness of such processes must be assessed by analyzing the toxicity of resulting effluents, for the monitoring of wastewater quality. To attain this purpose, this work intended to quantify the efficacy of a Lemna-based wastewater phytoremediation process, by analyzing toxicological effects of domestic and textile effluents. The toxic effects were measured in Lemna minor (same organisms used in the phytoremediation process, by quantifying toxicological endpoints such as root length, pigment content, and catalase activity) and by quantifying individual parameters of Daphnia magna (immobilization, reproduction, and behavior analysis). Phytoremediation process resulted in a decrease of chemical oxygen demand in both effluents and in an increase in root length of exposed plants. Moreover, textile effluent decreased pigments content and increased catalase activity, while domestic effluent increased the anthocyanin content of exposed plants. D. magna acute tests allowed calculating a EC50 and Toxic Units interval of 53.82–66.89%/1.85–1.49, respectively, to raw textile effluent; however, it was not possible to calculate these parameters for raw and treated domestic effluent (RDE and TDE). Therefore, in general, the acute toxicity of effluent toward D. magna was null for RDE, and mild for the treated textile effluent (TTE), probably due to the effect of phytoremediation. Exposure to textile effluents (raw and treated) increased the total number of neonates of D. magna and, in general, both textile effluents decreased D. magna distance swim. Moreover, although both effluents were capable of causing morphological and physiological/biochemical alterations in L. minor plants, organisms of this species were able to survive in the presence of both effluents and to remediate them.


Link to the publication :