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Accumulation of polyunsaturated fatty acids by cladocerans: effects of taxonomy, temperature and food
- MASCLAUX, HÃLÃNE, BEC, ALEXANDRE, KAINZ, MARTIN J., PERRIÃRE, FANNY, DESVILETTES, CHRISTIAN, BOURDIER, GILLES
- Freshwater biology 2012 v.57 no.4 pp. 696-703
- Ceriodaphnia, Cryptomonas, Daphnia magna, Daphnia pulex, Scenedesmus obliquus, arachidonic acid, biotransformation, diet, eicosapentaenoic acid, food webs, foraging, habitats, nutrients, seafoods, taxonomy, temperature, zooplankton
- 1.âZooplankton are important in transferring dietary nutrients, including polyunsaturated fatty acids (PUFA), up through aquatic food webs. 2.âWe tested the hypothesis that the taxonomic composition of zooplankton affects the retention and subsequent transfer of PUFA from upwards through the food web. Using laboratory experiments, we investigated dietary PUFA accumulation and bioconversion capacities of six cladoceran species (Ceriodaphnia sp., Daphnia longispina, Daphnia magna, Daphnia pulex, Scapholeberis mucronata and Simocephalus vetulus) fed on two diets (Scenedesmus obliquus and Cryptomonas sp.) that differed in their PUFA profiles. We performed experiments at two different temperatures (14 and 20âÂ°C) to assess the role of temperature in the trophic transfer of PUFA. 3.âThere was little variation in the concentrations of PUFA in these cladocerans which were controlled by dietary PUFA supply. Moreover, as expected, the concentrations of PUFA in all cladoceran species were higher at low temperature. 4.âHowever, even if the composition of PUFA in the cladoceran species generally corresponded to that in their diet, preferential accumulation of some PUFA was recorded in all these taxa. When fed on a highly unsaturated fatty acidâdeficient diet, all the cladocerans showed some ability to convert C18âPUFA into arachidonic acid and eicosapentaenoic acid. Interspecific variation in the ability to accumulate and bioconvert PUFA in cladocerans was more pronounced at low temperature (14âÂ°C) for both diets. 5.âOur results strongly suggest that in heterogeneous habitats with food partitioning between coâexisting cladocerans, foraging behaviour may affect the transfer of PUFA more strongly than interspecific variation in accumulating and/or bioconverting dietary PUFA.