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opencc-zeroMar 2022View details →

Data for fitness analyses used in: Environmentally-induced DNA methylation is inherited across generations in water fleas (Daphnia magna)

Data of fitness effects of environmental stressors on Daphnia magna over multiple generations. Ages of first and second reproduction, and sizes of first and second brood were measured and used to calculate replacement rate. This data is part of a study on whole-genome bisulphate sequencing on individual Daphnia magna to assess whether environmentally-induced DNA methylation can persist for up to four generations.

opencc-by-4.0Aug 2022View details →

Dataset for study from Duneau et al on Daphnia sperm evolution

Dataset on sperm size of several Daphnia species. Belong to the study on sperm evolution of Daphnia by Duneau, Möst and Ebert.

opencc-zeroOct 2022View details →

Dataset and scripts from: Dietary sterol availability modulates heat tolerance of Daphnia

The increasing frequency and intensity of summer heat waves is pushing freshwater zooplankton towards their upper thermal tolerance limits. At the same time, higher temperatures and prolonged water column stratification can favor the dominance of cyanobacteria in phytoplankton. Even when not toxic or grazing resistant, these prokaryotes lack phytosterols as essential precursors for cholesterol, the main sterol in animal tissues. Cholesterol plays a crucial role in the physiological adaptation of ectotherms to high temperature. Therefore, the shift to cyanobacteria-dominated systems may increase the vulnerability of zooplankton to heatwaves by intensifying cholesterol limitation. Here, we used death time curves that take into consideration the intensity and duration of a thermal challenge and a dynamic model to study the effects of cholesterol limitation on the heat tolerance of the keystone species Daphnia magna and to simulate the cumulative mortality that could occur in a fluctuating environment over several days of heatwave. We show that increasing cholesterol limitation does not affect the slope between time-to-immobilization and temperature, but does decrease the maximal temperature that Daphnia can withstand by up to 0.74°C. This seemingly small difference is sufficient to halve the time individuals can survive heat stress. Our simulations predicted that, when facing heatwaves over several days, the differences in survival caused by cholesterol limitation build up rapidly. Considering the anticipated intensity and duration of future (2070-2099) heatwaves, cholesterol limitation could increase mortality by up to 45% and 72% under low- and medium-greenhouse-gas-emission scenarios, respectively. These results suggest that the increasing risk of cholesterol limitation due to more frequent cyanobacterial blooms could compromise the resistance of zooplankton populations to future heatwaves. More generally, this study shows the importance of considering the nutritional context in any attempt to predict ectotherm mortality with increasing temperatures in the field.

opencc-zeroMay 2024View details →

Data for: Bi-modal response strategy in Daphnia to ambush predation risk

Predation, a well-established major selective force, can manifest through either consumptive or non-consumptive effects. The relative impact of such effects is predicted to vary depending on the predator hunting strategy. In aquatic systems, great attention has been paid to coursing predators, such as fish, and their effects on the behaviour of zooplankton. However, less information is available regarding more ambush-style predators. To remedy this paucity, we utilised a 3D-tracking platform to record groups of Daphnia magna under control or predation risk conditions from the ambush, invertebrate predator Erythromma najas. This design allowed us to test if there are anti-predator responses in multiple metrics of swimming behaviours. Furthermore, we recorded actual predation events allowing the distinction between predator exuded info-chemicals and those produced during the predation event. We demonstrate that predation risk was greatest for those that swam at 85% of the available depth and averaged 8.1 mm/s. Examining each individuals swimming behaviour separately shows that predation risk did not exert an impact on any of the prey response metrics. Interestingly, however, we show that Daphnia conform to one of two strategies whilst under predation risk; either swim fast high up in the water column or swim slowly close to the bottom. Hence, this dichotomous behaviour is driven by strategies combining speed and depth in different constellations. As a result, our study demonstrates that Daphnia can detect the presence of a predator, but not immediately the act of predation. In a broader context, our findings highlight the importance of considering both the spatial and temporal dimensions of predation events in order correctly detect anti-predator responses. The data here is the raw positions of each individual tracked for the above study.

opencc-by-4.0Jun 2024View details →

Data and code for "Salomon et al. 2024: Effects of dissolved organic matter on the toxicity of micro- and nanoplastic particles to Daphnia - a meta-analysis."

<div> All data and R code for Salomon S, Grubmüller E, Kropf P, Nickl E, Rühl A, Weigel S, Becker F, Antonio Vital AL, Laforsch C, Schott M, Mair MM. (2024). Effects of dissolved organic matter on the toxicity of micro- and nanoplastic particles to Daphnia - a meta-analysis. Microplastics and Nanoplastics. (<a href="https://doi.org/10.1186/s43591-024-00088-4" target="_blank" rel="noopener">https://doi.org/10.1186/s43591-024-00088-4</a>) Abstract Effects of micro- and nanoplastic particles (MNP) on organisms have been increasingly reported in recent years, with a large number of studies conducted on water fleas of the genus Daphnia. Most of the available studies used pristine particles that have not been exposed to the environment or to organic substances. In natural environments, however, organic substances like dissolved organic matter (DOM) attach to the MNP, forming an ecocorona on the particles’ surface. How the formation of an ecocorona influences MNP toxicity is still uncertain. While some studies suggest that DOM can mitigate the negative effects of MNP on organisms, other studies did not find such associations. In addition, it is unclear whether the DOM attached to the particles’ surface is attenuating the effects of MNP directly or whether co-exposure with DOM solved in the medium attenuates MNP toxicity indirectly, for instance by increasing Daphnia‘s resilience to stressors in general. To draw more solid conclusions about the direction and size of the mediating effect of DOM on MNP-associated immobilization in Daphnia spp., we synthesized evidence from the published literature and compiled 305 data points from 13 independent studies. The results of our meta-analysis show that the toxic effects of MNP are likely reduced in the presence of certain types of DOM in the exposure media. We found similar mediating effects when MNP were incubated in media containing DOM before the exposure experiments, although to a lesser extent. Future studies designed to disentangle the effects of DOM attached to the MNP from the general effects of DOM in the exposure medium will contribute to a deeper mechanistic understanding of MNP toxicity in nature and enhance the reliability of MNP risk assessment. </div>

opencc-by-4.0Dec 2013View details →

Fig. 2 in Optimisation Of Dna Extraction And Rapd-Pcr Amplification For Population Genetic Analysis Of Daphnia Cucullata Sars, 1862 (Crustacea: Cladocera)

Fig. 2. RAPD fingerprints results from different samples of Daphnia cucullata with primers OPA-03 and OPA-05 (M- marker, 1-11 runners- different samples of Daphnia cucullata; 12- control) using RAPD-PCR 10 × Taq buffer with (NH4)2SO4.

opencc-by-4.0Dec 2017View details →

Fig. 4 in Use Of Acutodesmus Dimorphus (Turpin) Tsarenko As A Fodder Organism For Daphnia Growing

Fig. 4. Nutrients content in Daphnia magna biomass when using different feeding schemes, where: 1 – Daphnia, introduced simultaneously with algae; 2 – Daphnia using algae as a feed substrate.

opencc-by-4.0Dec 2017View details →

Fig. 1 in Use Of Acutodesmus Dimorphus (Turpin) Tsarenko As A Fodder Organism For Daphnia Growing

Fig. 1. The content of proteins, lipids, carbohydrates and carotenoids in A. dimorphus biomass at the terminal stage of cultivation on waste water from RAS.

opencc-by-4.0Dec 2013View details →

Fig.1 in Optimisation Of Dna Extraction And Rapd-Pcr Amplification For Population Genetic Analysis Of Daphnia Cucullata Sars, 1862 (Crustacea: Cladocera)

Fig.1. RAPD fingerprints results from different samples of Daphnia cucullata with primers OPA-03 and OPA-05 (M- marker, 1-16 runners- different samples of Daphnia cucullata; 17- control) using RAPD-PCR 10 × Taq buffer with KCl.

opencc-by-4.0Dec 2022View details →

Рис. 1. Daphnia (D.) curvirostris. Партеногенетическая самка: А — гоΛова с боковой стороны, Б — постабΑомен Fig. 1. Daphnia (D.) curvirostris. Parthenogenetic female: А — head, lateral view, Б — postabdomen, lateral view in Zooplankton species diversity in technogenic reservoirs of the Southeastern Transbaikalia

Рис. 1. Daphnia (D.) curvirostris. Партеногенетическая самка: А — гоΛова с боковой стороны, Б — постабΑомен Fig. 1. Daphnia (D.) curvirostris. Parthenogenetic female: А — head, lateral view, Б — postabdomen, lateral view

opencc-by-4.0Jan 2014View details →

Figure 1 in Morphological examination of the resting egg structure of 3 cladoceran species [Ceriodaphnia quadrangula (O. F. Müller, 1785), Daphnia longispina (O. F. Müller, 1776), and D. magna Straus, 1820]

Figure 1. Resting egg photos of 3 species (Daphnia magna, D. longispina, Ceriodaphnia quadrangula). A) SEM photo of C. quadrangula, B) SEM photo of D. longispina, C) SEM photo of D. magna, D) light microscope photo of C. quadrangula, E) light microscope photo of D. longispina, F) light microscope photo of D. magna.

Figure 5 in Ecotoxicological investigation of cyanobacterial crude extracts to Daphnia magna under subchronic test conditions

Figure 5. Filtration (A) and ingestion (B) rates of Daphnia magna after exposing to cyanobacterial crude extracts. Asterisks indicate significant differences by the Kruskal-Wallis test, followed by the Wilcoxon rank-sum test for multiple comparison (*P ≤.05).

Figure 2 in Ecotoxicological investigation of cyanobacterial crude extracts to Daphnia magna under subchronic test conditions

Figure 2. The degradation of eggs and neonates (red arrows) of the Daphnia magna gravid females exposed to cyanobacterial crude extracts. A: dead eggs, B: dead neonate, C: malformation of the tail, and D: normal tail of control Daphnia magna.

Figure 1 in Ecotoxicological investigation of cyanobacterial crude extracts to Daphnia magna under subchronic test conditions

Figure 1. The effects of cyanobacterial crude extracts on the brood size. A: the first brood, B: the second brood. Asterisks indicate significant differences by the Kruskal-Wallis test, followed by the Wilcoxon rank-sum test for multiple comparison (*P <.05, **P <.01, ***P <.001).

Figure 3 in Ecotoxicological investigation of cyanobacterial crude extracts to Daphnia magna under subchronic test conditions

Figure 3. Regression equations and correlation coefficients (R2) describing the highest correlations between the number of neonates per female (as mean) and CCE concentrations. The red color indicates the microcystin-containing crude extract and the green color indicates the microcystin-free crude extract.

Figure 4 in Ecotoxicological investigation of cyanobacterial crude extracts to Daphnia magna under subchronic test conditions

Figure 4. The effects of cyanobacterial crude extracts on somatic growth of Daphnia magna. Asterisks indicate significant differences by the Kruskal-Wallis test, followed by the Wilcoxon rank-sum test for multiple comparison (*P <.05, **P <.01, ***P <.001).

opencc-by-4.0Jul 2015View details →

FIGURE 1 in Findings of Daphnia (Ctenodaphnia) Dybowski et Grochowski (Branchiopoda: Cladocera) in Cenozoic volcanogenic lakes in Germany, with discussion of their indicator value

FIGURE 1. Fossils from Randeck Maar, rock fragment, SMNS 101.665: 1 - whole rock fragment with paper arrows pointing out the impressions of Daphnia (Ctenodaphnia) parthenogenetic females in upper (yellowish) layer. 2 - its side portion, with visible alternation of yellowish and grayish layers. 3 - adult female, lateral view. 4 - two females, dorso-lateral view. 5 - dorsal view. 6-7 - lateral view and antenna II. 8 - ephippium in grayish layer. All scales equal 1 mm. Abbreviations: aII - antenna II; cn - caudal needle; el - egg loculus.

opencc-by-4.0Jul 2015View details →

FIGURE 2 in Findings of Daphnia (Ctenodaphnia) Dybowski et Grochowski (Branchiopoda: Cladocera) in Cenozoic volcanogenic lakes in Germany, with discussion of their indicator value

FIGURE 2. Fossils from Rott in the collection of SIUB. 1 - ephippium, syntype of Daphnia fossilis von Heyden, 1862, fragment A557. 2 - presumable adult female, A 648bB. 3-4 - clusters of ephippia attached to small sticks, A654 and A644a. 5-8 - general view of ephippia, A644a, A647 (two), A654b. All scales equal 1 mm. Abbreviations: ap - anterior projection; el - egg loculus.

opencc-zeroJul 2021View details →

Fitness cost from fluctuating ultraviolet radiation in Daphnia magna

Solar ultraviolet radiation (UVR) is an important environmental threat for organisms in aquatic systems, but its temporally variable nature makes the understanding of its effects ambiguous. The aim of our study was to assess potential fitness costs associated with fluctuating UVR in the aquatic zooplankter Daphnia magna. We investigated individual survival, reproduction and behaviour when exposed to different UVR treatments. Individuals exposed to fluctuating UVR, resembling natural variations in cloud cover, had the lowest fitness (measured as the number of offspring produced during their lifespan). In contrast, individuals exposed to the same, but constant UVR dose, had similar fitness as control individuals (not exposed to UVR), but they showed a significant reduction in daily movement. The re-occurring threat response to the fluctuating UVR treatment thus had strong fitness costs for D. magna, and we found no evidence for plastic behavioural responses when continually being exposed to UVR, despite the regular, predictable exposure schedule. In a broader context, our results imply that depending on how variable a stressor is in nature, populations may respond with alternative strategies, a framework that could promote rapid population differentiation and local adaptation.