Multiple Trophic Markers Trace Dietary Carbon Sources in Barents Sea Zooplankton During Late Summer
Multiple Trophic Markers Trace Dietary Carbon Sources in Barents Sea Zooplankton During Late Summer
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DOI：
10.3389/fmars.2020.610248
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发表时间：
2021-01
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通讯作者：
D. Kohlbach;H. Hop;A. Wold;K. Schmidt;L. Smik;S. Belt;Amalia Keck Al-Habahbeh;M. Woll;M. Graeve;A. Dabrowska;A. Tatarek;A. Atkinson;P. Assmy
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作者：
D. Kohlbach;H. Hop;A. Wold;K. Schmidt;L. Smik;S. Belt;Amalia Keck Al-Habahbeh;M. Woll;M. Graeve;A. Dabrowska;A. Tatarek;A. Atkinson;P. Assmy
我们调查了24个巴伦支海浮游动物类群的饮食，以了解浮游食物网过程在夏末，包括海冰藻类产生的碳的重要性。这是通过结合来自多个和互补的营养标记方法的见解来构建喂养的各个方面。具体而言，我们确定了藻类产生的脂肪酸（FA）的比例，以反映依赖硅藻与甲藻衍生的碳，高度分支的类异戊二烯（HBI）的脂质，区分冰相关的和远洋的碳源，和甾醇，以表明食肉的程度。桡足类有最强的硅藻信号的基础上FA，而缺乏海冰藻类相关的HBIs（IP 25，IPSO 25）表明，他们的浮游生物，而不是冰相关的硅藻。端足类Themisto libellula和栉水母Beroë cucumis和Mertensia ovum对甲藻产生的FA有较高的贡献。在这个食物网中存在着高度的肉食性，如FA肉食性指数18：1（n−9）/18：1（n−7）所示（仅在翼足类Clione limacina中平均值< 1），在大多数类群中存在着与桡足类相关的FA，而在小型桡足类类群中没有藻类产生的HBI，如Oithona similis和Pseudocalanus spp。HBIs和植物甾醇的浓度之间的一致性，在个人建议，植物甾醇提供了一个很好的额外指示藻类摄入。在6种浮游动物（发生在磷虾，片足类，翼足类，和apphecularians）中检测到海冰藻类相关的HBIs，表明从夏末海冰到远洋消费的冰相关碳的整体低至中等的贡献。然而，在翼足类动物和approximularians的冰衍生HBIs的意外发生，表明沉积冰衍生材料的重要性，至少在一年中的这个时候的水柱内的滤食性动物。
We investigated diets of 24 Barents Sea zooplankton taxa to understand pelagic food-web processes during late summer, including the importance of sea ice algae-produced carbon. This was achieved by combining insights derived from multiple and complementary trophic marker approaches to construct individual aspects of feeding. Specifically, we determined proportions of algal-produced fatty acids (FAs) to reflect the reliance on diatom- versus dinoflagellate-derived carbon, highly branched isoprenoid (HBI) lipids that distinguish between ice-associated and pelagic carbon sources, and sterols to indicate the degree of carnivory. Copepods had the strongest diatom signal based on FAs, while a lack of sea ice algae-associated HBIs (IP25, IPSO25) suggested that they fed on pelagic rather than ice-associated diatoms. The amphipod Themisto libellula and the ctenophores Beroë cucumis and Mertensia ovum had a higher contribution of dinoflagellate-produced FAs. There was a high degree of carnivory in this food web, as indicated by the FA carnivory index 18:1(n−9)/18:1(n−7) (mean value < 1 only in the pteropod Clione limacina), the presence of copepod-associated FAs in most of the taxa, and the absence of algal-produced HBIs in small copepod taxa, such as Oithona similis and Pseudocalanus spp. The coherence between concentrations of HBIs and phytosterols within individuals suggested that phytosterols provide a good additional indication for algal ingestion. Sea ice algae-associated HBIs were detected in six zooplankton species (occurring in krill, amphipods, pteropods, and appendicularians), indicating an overall low to moderate contribution of ice-associated carbon from late-summer sea ice to pelagic consumption. The unexpected occurrence of ice-derived HBIs in pteropods and appendicularians, however, suggests an importance of sedimenting ice-derived material at least for filter feeders within the water column at this time of year.