Search results for "DAPHNIA MAGNA"
showing 8 items of 68 documents
Data from: Phosphorus limitation enhances parasite impact: feedback effects at the population level
2014
Background: Nutrient deficiency affects the growth and population dynamics of consumers. Endoparasites can be seen as consumers that drain carbon (C) or energy from their host while simultaneously competing for limiting resources such as phosphorus (P). Depending on the relative demands of the host and the parasite for the limiting nutrient, intensified resource competition under nutrient limitation can either reduce the parasite?s effect on the host or further reduce the fitness of the nutrient-limited host. So far, knowledge of how nutrient limitation affects parasite performance at the host population level and how this affects the host populations is limited. Results: We followed the po…
Efficiency of Daphnia magna in removal of green microalgae cultivated in Nordic recirculating aquaculture system wastewater
2020
The increase of global aquaculture production has boosted the development of recirculating aquaculture systems not only because they reduce water use but also provide opportunities for waste management and the use of released nutrients. The dissolved nutrients can be efficiently removed from recirculating aquaculture system wastewater by microalgae, and microalgae can be harvested from the wastewater with low costs by zooplankton such as Daphnia. The purpose of this study was to evaluate the feasibility of using microalgae and Daphnia for bioremediation of recirculating aquaculture system wastewater in Nordic conditions. We evaluated the growth and filtration efficiency of the waterflea Dap…
Chronic toxicity of diazinon todaphnia magna:Effects on survival, reproduction and growth
1995
The sublethal effect of 0.15, 0.18, 0.22, 0.25 and 0.30 μg/L diazinon on the survival, reproduction and growth of D. magna was monitored for 21 days. Neonates (≤ 24 h) were obtained from the stock cultures and raised individually in 50 mL glass beakers. All daphnids were transfered every other day to a new beaker containing fresh medium, food and the appropriate pesticide concentration. The animals were maintained in an environmental chamber at 22±1°C on a 12L: 12D photoperiod and were fed daily on 5 x 105 cell/mL of the green algae Nannochloris oculata. The parameters used to determine the effect of the pesticide on reproduction were: mean total young per female, mean brood size, mean numb…
Data from: Daphnia females adjust sex allocation in response to current sex ratio and density
2019
Cyclical parthenogenesis presents an interesting challenge for the study of sex allocation, as individuals’ allocation decisions involve both the choice between sexual and asexual reproduction, and the choice between sons and daughters. Male production is therefore expected to depend on ecological and evolutionary drivers of overall investment in sex, and those influencing male reproductive value during sexual periods. We manipulated experimental populations, and made repeated observations of natural populations over their growing season, to disentangle effects of population density and the timing of sex from effects of adult sex ratio on sex allocation in cyclically parthenogenetic Daphnia…
Characteristics of acute toxicity dynamics of selected toxicants on aquatic crustaceans
2019
Determining the value of a half-effective or half-life concentration or dose of toxicant is the main purpose of acute toxicity studies, and this is also the most commonly used value in the toxicity characteristics of substances. By conducting tests that meet the criteria and requirements for the determination of acute toxicity, due to the use of appropriate mathematical tools and concentrations resulting in complete lethal effects in the studied groups, considerably more important values can be achieved, which give a possibility for the analysis of the entire process's dynamics, as well as determining the threshold values of the effect time and toxicant concentration. This was the purpose o…
Evaluación de los efectos producidos en diferentes niveles de organización biológica en Daphnia magna tras la exposición al fungicida procloraz y al …
2021
Desde hace décadas, el uso de plaguicidas sintéticos ha permitido optimizar el rendimiento en la producción de alimentos y continúa siendo la forma más rentable de prevenir y/o erradicar las plagas que amenazan su viabilidad y prosperidad. Lamentablemente, casi tres cuartas partes de los recursos hídricos dulceacuícolas son destinados a la producción agrícola, convirtiéndose así en una de las principales vías por la que los plaguicidas acceden al medio acuático natural. En España, dos de los plaguicidas de mayor uso son el fungicida procloraz y el insecticida piriproxifen. Ambos detectados en diferentes sistemas fluviales como los ríos Ebro, Guadalquivir, o Turia. Su llegada a estos ecosist…
Hydrogen isotopes (δ2H) of polyunsaturated fatty acids track bioconversion by zooplankton
2022
1. Organisms at the base of aquatic food webs synthesize essential nutrients, such as omega-3 polyunsaturated fatty acids (n-3 PUFA), which are transferred to consumers at higher trophic levels. Many consumers, requiring n-3 long-chain (LC) PUFA, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have limited ability to biosynthesize them from the essential dietary precursor α-linolenic acid (ALA) and thus rely on dietary provision of LC-PUFA. 2. We investigated LC-PUFA metabolism in freshwater zooplankton using stable hydrogen isotopes (δ2H) of fatty acids as tracers. We conducted feeding experiments with the freshwater keystone grazer Daphnia to quantify changes in the δ2…
Phosphorus limitation enhances parasite impact: feedback effects at the population level
2014
Background Nutrient deficiency affects the growth and population dynamics of consumers. Endoparasites can be seen as consumers that drain carbon (C) or energy from their host while simultaneously competing for limiting resources such as phosphorus (P). Depending on the relative demands of the host and the parasite for the limiting nutrient, intensified resource competition under nutrient limitation can either reduce the parasite’s effect on the host or further reduce the fitness of the nutrient-limited host. So far, knowledge of how nutrient limitation affects parasite performance at the host population level and how this affects the host populations is limited. Results We followed the popu…