Is the fatty acid composition of <i>Daphnia galeata </i>determined by the fatty acid composition of the ingested diet?

Weers, Paul M.M.; Siewertsen, K.; Gulati, R. D.

doi:10.1046/j.1365-2427.1997.00238.x

Cited by 82 publications

(78 citation statements)

References 16 publications

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“…COL was the only lake in which H. gibberum dominated, which suggests that H. gibberum contains low DHA concentrations and reinforces the hypothesis that patterns of DHA retention will change when different zooplankton species dominate. For example, it has generally been observed that cladocerans (Weers et al 1997;Ballantyne et al 2003) contain less DHA than copepods (Desvilettes et al 1997). …”

Section: Discussionmentioning

confidence: 99%

Essential fatty acids in the planktonic food web and their ecological role for higher trophic levels

Kainz

Arts

Mazumder

2004

Limnology & Oceanography

299

222

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We measured concentrations of essential fatty acids (EFAs) in four size categories of planktonic organismsseston (10-64 m), microzooplankton (100-200 m), mesozooplankton (200-500 m), and macrozooplankton (Ͼ500 m)-and in rainbow trout (Oncorhynchus mykiss) in coastal lakes. Size-dependent patterns in concentrations of specific fatty acids (FAs) are important for ecosystem function, because planktivorous fish and some invertebrates are size-selective predators. We demonstrate that the retention of individual FAs differs among the four size categories of planktonic organisms in our study systems. Changes in individual EFA concentrations within the planktonic food web were similar in all coastal lakes sampled, which indicates the generality of our findings. Although concentrations of arachidonic acid, eicosapentaenoic acid (EPA), and linoleic acid increased steadily with plankton size, the concentration of ␣-linolenic acid decreased slightly in larger size fractions of zooplankton. Concentrations of another EFA, docosahexaenoic acid (DHA), declined sharply from mesozooplankton to the cladoceran-dominated macrozooplankton size class. Our results indicate that the retention of EFAs, as a function of plankton size, is related, in part, to the taxonomic composition of planktonic food webs. We suggest that, in general, zooplankton exhibit an EPA-retentive metabolism with increasing body size, whereas different taxonomic groups within the planktonic food web retain DHA differently. Finally, we conclude that EPA is highly retained in zooplankton, whereas in rainbow trout DHA is highly retained.

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Section: Discussionmentioning

confidence: 99%

Essential fatty acids in the planktonic food web and their ecological role for higher trophic levels

Kainz

Arts

Mazumder

2004

Limnology & Oceanography

299

222

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“…In Daphnia species, the n-6 PUFAs found in Colpidium campylum (18:2n-6, 18:3n-6) might be further converted into 20:4n-6, an intermediate in prostaglandin synthesis (Weers et al 1997). However, laboratory experiments and correlative field studies suggest either 18:3n-3 or 20:5n-3 as a potentially limiting resource that constrains proper growth of Daphnia spp.…”

Section: Discussionmentioning

confidence: 99%

“…In Cyclidium sp., comparatively high amounts of n-3 PUFA (18:3n-3, 18:4n-3) were detected, which, in Daphnia spp., can be converted into 20:5n-3 through a process of elongation and desaturation. Although the conversion of 18:3n-3 into 20:5n-3 is low (Weers et al 1997, Von Elert 2002, the availability of these PUFAs might be adequate to meet metabolic demands. Even though Cyclidium sp.…”

Section: Discussionmentioning

confidence: 99%

Trophic upgrading of picocyanobacterial carbon by ciliates for nutrition of Daphnia magna

Martin‐Creuzburg¹,

Bec²,

Elert³

2005

Aquat. Microb. Ecol.

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Unicellular picocyanobacteria, such as species of the genus Synechococcus, are unsuitable for supporting growth and reproduction of Daphnia spp. In Synechococcus spp., long-chain polyunsaturated fatty acids (PUFAs) and sterols are absent, which leads to a low carbon transfer efficiency at the picocyanobacteria-Daphnia spp. interface. Herein, we address the question as to whether ciliates can serve as a trophic link between picocyanobacterial production and Daphnia spp. production, thereby upgrading the nutritional value of a picocyanobacterial food source by producing essential lipids such as PUFAs or sterols. In simplified experimental food chains consisting of 1 of 2 different Synechococcus strains, the ciliates Colpidium campylum or Cyclidium sp., and D. magna, we provided evidence that predation on ciliates by Daphnia spp. allows access to picocyanobacterial production. Since daphnids are primarily sterol-limited when grown on the picocyanobacteria Synechococcus spp., the observed trophic upgrading of Synechococcus food-quality by intermediary ciliates is most probably due to the addition of sterols or sterol-like compounds that (at least partly) release Daphnia spp. from sterol limitation. The absence of sterols in the ciliates used in the present study suggests that tetrahymanol and/or hopanoids provide functional equivalents of sterols not only in ciliates but also in Daphnia spp., thereby leading to enhanced growth of the cladocerans.

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“…In two separate studies copepods and daphniids were cultured with Cryptomonas sp., and the fatty acid pattern of each zooplankton was determined. Daphniids showed a high x3:x6 ratio of 12.8 (from Weers et al, 1997) and Eudiaptomus a lower x3:x6 ratio 5.8 (from von Elert & Stampfl, 2000). These patterns suggest different requirements for different fatty acids between copepods and cladocerans (Boersma & Stelzer, 2000), which could have as a consequence that different fatty acids are left in the seston in a similar way that macronutrients are recycled differently by cladocerans and copepods (Rothhaupt, 1997), although it seems to be the case that the daphniids with their non-selective feeding mode reflect the seston much more than the copepods.…”

Section: Discussionmentioning

confidence: 99%

Differential Impacts of Copepods and Cladocerans on Lake Seston, and Resulting Effects on Zooplankton Growth

Becker

Feuchtmayr

Brepohl³

et al. 2004

Hydrobiologia

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In an enclosure study in Scho¨hsee, a small mesotrophic lake in Northern Germany, the impact of copepods and daphniids on the seston community was studied. In general, these two guilds differ in their feeding behaviour. Copepods actively select their food, with a preference for larger particles, whereas most cladocerans are unselective filter-feeders. In this study we investigate how the impact of the two different grazers affects zooplankton growth. We combine results obtained in the laboratory with results measured in situ in the enclosures. Copepods and cladocerans were cultured on seston from enclosures that were inhabited by density gradients of copepods or daphniids. We observed that Daphnia grew faster on seston that was pre-handled by copepods than on seston that was pre-handled by daphniids, and that somatic growth decreased with increasing densities of daphniids in the enclosures. In contrast, we observed no differences in development rates for copepods grown on the different media. The population growth rates of Daphnia in the Daphnia treatments were determined in the enclosures. Growth differences in both somaticand population growth of Daphnia were correlated to food quality aspects of the seston. In the laboratory we found that Daphnia growth was correlated with several fatty acids. The strongest regression was with the concentration of 20:4x3 (r 2 ¼ 0.37). This particular fatty acid also showed the highest correlation with growth after normalisation of the fatty acids to the carbon content of the enclosures (r 2 ¼ 0.33). On the other hand, in the enclosure the population growth correlated most to the particulate nitrogen content (r 2 ¼ 0.78) and only to the N:C ratio, when normalised to carbon (r 2 ¼ 0.51).

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Is the fatty acid composition of Daphnia galeata determined by the fatty acid composition of the ingested diet?

Cited by 82 publications

References 16 publications

Essential fatty acids in the planktonic food web and their ecological role for higher trophic levels

Essential fatty acids in the planktonic food web and their ecological role for higher trophic levels

Trophic upgrading of picocyanobacterial carbon by ciliates for nutrition of Daphnia magna

Differential Impacts of Copepods and Cladocerans on Lake Seston, and Resulting Effects on Zooplankton Growth

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