The essential fatty acids (EFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are critical nutrients for all organisms, and the temperature sensitivity of their trophic transfer in marine systems is of concern because of rising ocean temperatures. Laboratory-reared copepodites of the marine calanoid Calanus finmarchicus were used to test the effects of temperature (at 6°C, 12°C and increasing temperature stress) and prey type (the dinoflagellate Heterocapsa triquetra and the diatom Thalassiosira weissflogii ) on the extent and efficiency of dietary EPA and DHA incorporation from phytoplankton to copepods in a set of feeding experiments using 13 C labelling. Temperature was a significant determinant of C . finmarchicus copepodites' EFA incorporation and gross growth efficiency, defined as the fraction of ingested EFA retained in copepod tissue. Ingestion and incorporation of both EFA were higher at warmer temperature, except in the case of DHA in copepods feeding on diatoms. DHA-associated growth efficiency was higher at the higher temperature for copepodites consuming the dinoflagellate, but temperature-related variation in algal EFA content was also a predictive factor. Moreover, our results strongly suggest that copepodites are capable of synthesizing EPA when consuming an EPA-depleted diet. Our study implies that the copepod link of marine food webs is resilient in terms of EFA transfer when confronted with alterations of ambient temperature and prey type availability. Measurements presented here are critical for estimating how EFA transfer dynamics respond to intra- and interannual environmental variability. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers’: evidence and significance of consumer modification of dietary fatty acids’.

中文翻译：

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环境温度和藻类猎物类型影响草食海洋桡足类的必需脂肪酸掺入和营养升级

必需脂肪酸（EFA）、二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）是所有生物体的关键营养物质，由于海洋温度上升，它们在海洋系统中营养转移的温度敏感性受到关注。实验室饲养的海洋巨蜥桡足类鳍马哲哲用于测试温度（6°C、12°C 和增加温度应激）和猎物类型（甲藻）的影响三角异壳藻和硅藻魏氏海链藻）在一组饲喂实验中，研究了从浮游植物到桡足类的膳食 EPA 和 DHA 掺入的程度和效率13C 标签。温度是一个重要的决定因素C。芬马奇库斯桡足类的 EFA 掺入量和总生长效率，定义为摄入的 EFA 保留在桡足类组织中的比例。除了以硅藻为食的桡足类中的 DHA 之外，在较高温度下，两种 EFA 的摄入和掺入量都较高。对于消耗甲藻的桡足类来说，与 DHA 相关的生长效率在较高温度下较高，但藻类 EFA 含量与温度相关的变化也是一个预测因素。此外，我们的结果强烈表明，桡足类在食用缺乏 EPA 的饮食时能够合成 EPA。我们的研究表明，当面临环境温度和猎物类型可用性的变化时，海洋食物网的桡足类链接在全民教育转移方面具有弹性。这里提出的测量对于估计全民教育转移动态如何响应年内和年际环境变化至关重要。本文是主题“脂质作为‘营养生物标志物’的下一个前景：消费者改变膳食脂肪酸的证据和意义”的一部分。