Taxonomic differences in the essential fatty acid composition of groups of freshwater zooplankton relate to reproductive demands and generation time

Abstract

1. Marked differences were observed in the total fatty acid concentrations and essential fatty acid (EFA) distributions of co-existing freshwater copepods and cladocerans in four large lake systems (lakes Michigan, Erie, Ontario and Champlain) over two growing seasons. These patterns appeared independent of lake seston EFA composition. 2. Compared to the cladocerans, calanoid and cyclopoid copepods contained significantly higher concentrations of total fatty acids and docosahexaenoic acid (DHA), an EFA abundant in fish. Calanoids and cladocerans contained similar levels of eicosapentaenoic acid (EPA), but cladocerans showed EPA : DHA ratios consistently greater than those of the available seston food source. Alpha-linolenic acid was most abundant in the herbivorous cladocerans, Daphnia and Holopedium, while the highest concentrations of arachidonic acid were found in the predatory cladocerans, Bythotrephes longimanus and Leptodora kindtii. 3. The distinct EFA accumulation patterns between cladoceran and copepod zooplankton suggest metabolic regulation of certain EFAs to meet the particular physiological demands and ecological strategies of these different zooplankton groups. Cladocerans may accumulate EPA directly from their diet, or through transformation of dietary materials to facilitate rapid somatic growth and enhance reproduction due to their short generation time. In contrast, copepods may retain DHA to increase their cell membrane fluidity in order to remain active over the winter due to their longer generation time and life cycle. 4. Consistent EFA differences between zooplankton groups may have implications regarding the somatic growth and reproductive success of different zooplankton taxa as well as the nutritional value of various zooplankton groups for larval and planktivorous fish.

Influence of food web structure on the biochemical composition of seston, zooplankton and recently deposited sediment in experimental freshwater mesocosms

“…high abundance of Cryptophyceae rich in long-chain PUFAs in fishless enclosures versus predominance of Chlorophyceae lacking these essential long-chain fatty acids in fish enclosures. This result is consistent with the correlations observed between the essential PUFA content in some zooplankton species and that of their algal diet (Kainz et al 2004;Brett et al 2006;Persson and Vrede 2006;Smyntek et al 2008).…”

Seasonal shifts between autochthonous and allochthonous carbon contributions to zooplankton diets in a subarctic lake

“…For instance, copepods and cladocerans have different metabolic means to cope in cold temperatures. Copepods are able to change their cellular components to more highly unsaturated fatty acids in winter, while cladocerans rely on different fatty acids to maintain cellular fluidity (Smyntek et al 2008;Mariash et al in press). These physiological adaptations ultimately affect diet and feeding rates of cold-tolerant species, which was also the case in this study, where copepods in cold winter temperatures stopped feeding but D. umbra continued feeding on heterotrophic food items.…”

Comparison of fatty acids profile and antioxidant enzyme level of cladoceran Moina brachiata (jurine, 1820) from freshwater bodies of Chennai

“…Tough correlations among seston FA profiles in polar lipids and those in Daphnia have been shown in the field study [4].Moreover, Moreover, few authors have been reported a mismatch between FA composition of zooplankton and its food in natural water bodies [10], [1].…”

“…Zooplankton plays a key role in the transfer of PUFA to organisms such as fish [1]. The accumulation of PUFA an invertebrate prey then influences fish production significantly [2].…”