Combined effects of the 4-nonylphenol and fish kairomones on the survival, morphology and life history traits of Daphnia magna Straus

Özcan, Hatice Elif
Daphnia has evolved morphological and life history defenses against predators and these appear to be mediated by chemicals (kairomones) released by the predator. Furthermore, anthropogenic stressors including alkylphenols have been shown to affect several characteristics of Daphnia. Daphnia magna that were grown in the fish-conditioned water and nonfish- conditioned water were exposed to 0.005, 0.01, 0.05, 0.15, 0.5 mg l'1 NP concentrations in the acute toxicity and 0.001, 0.005, 0.01 mg l"1 NP concentrations in the chronic toxicity experiments. In the chronic toxicity experiment, two different food levels were used. The 24 and 48h LC50 values of NP for the individuals were determined as 0.394 mg l"1 and 0.149 mg l"1, respectively in the presence of fish kairomone. 111However, in the absence of fish kairomone LC50 values could not be calculated due to high survival rate. In the chronic toxicity experiment, fish kairomone and NP significantly decreased the survival of the test organisms compared to the effects of either treatment. The effect of fish kairomone was stronger than the NP concentrations; however, at the highest NP concentration the effect was pronounced. Presence of fish kairomone and NP together significantly increased the maturation time whereas fish kairomone itself significantly decreased the maturation size. The high food level and the NP doses increased the helmet size, and the former also increased clutch size. In conclusion, exposure to fish kairomones enhanced the sensitivity to the NP doses, which were very low in this study, through reducing the survival and affecting the life history characteristics.


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Extreme Oxatriquinanes: Structural Characterization of alpha-Oxyoxonium Species with Extraordinarily Long Carbon-Oxygen Bonds
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The first stable alpha-oxyoxonium species have been synthesized and characterized. Strong donation of nonbonding electrons on oxygen into the adjacent sigma*(C-O+) orbital was predicted by modeling to result in unheard of carbon-oxygen bond lengths. The kinetic stability of the triquinane ring system provides a platform upon which to study these otherwise elusive species, which are evocative of intermediates on the acetalization reaction pathway. Crystallographic analysis of the alpha-hydroxy and alpha-meth...
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Species that have been translocated and otherwise manipulated by humans may show patterns of population structure that reflect those interactions. At the same time, natural processes shape populations, including behavioural characteristics like dispersal potential and breeding system. In Europe, a key factor is the geography and history of climate change through the Pleistocene. During glacial maxima throughout that period, species in Europe with temperate distributions were forced south, becoming distribut...
Citation Formats
H. E. Özcan, “Combined effects of the 4-nonylphenol and fish kairomones on the survival, morphology and life history traits of Daphnia magna Straus,” M.S. - Master of Science, Middle East Technical University, 0.