1. The structure of food webs provides important insight into biodiversity, organic matter (OM) pathways, and ecosystem functioning.
2. Stable isotope analysis (δ¹³C and δ¹⁵N) was used to characterize the trophic structure and the main OM pathways supporting food webs in the Rapa Nui coastal marine ecosystem.
3. The trophic position of consumers and isotopic niche metrics were estimated for different assemblages (i.e. mesozooplankton, emergent zooplankton, reef invertebrates, reef fishes, pelagic fishes, and seabirds). Furthermore, the relative importance of different OM sources (i.e. macroalgae, zooxanthellate corals, and particulate OM [POM]) was assessed for heterotrophic consumers using Bayesian mixing model (MixSIAR).
4. Results show a clear pattern of ¹³C and ¹⁵N enrichment from small‐sized pelagic and benthic invertebrates, to reef and pelagic fishes, and seabirds. Most invertebrates were classified as primary consumers, reef fishes as secondary consumers and pelagic predators and seabirds as tertiary and quaternary consumers.
5. Isotopic niche metrics indicate a low trophic diversity for pelagic assemblages (mesozooplankton and pelagic fishes), in contrast to reef fauna (invertebrates and fishes), whose higher trophic diversity suggest the exploitation of a wider range of trophic resources. Overlapping of standard ellipses areas between reef invertebrates and reef fishes indicates that both assemblages could be sharing trophic resources.
6. Mixing models results indicate that POM is the main trophic pathway for mesozooplankton, macroalgae (Rhodophyta) for emergent zooplankton, and a mix of coral‐derived OM and Rhodophyta for coral reef assemblages such as macrobenthos and reef invertebrates. In contrast, POM contribution was notably more important for some pelagic fishes and seabirds from upper trophic levels.
7. This study provides key elements for conservation efforts on coral reefs, management planning and full‐implementation of the recently created Rapa Nui Multiple Use Marine Protected Area.

中文翻译：

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通过Rapa Nui（复活节岛）的海洋生态系统追踪营养路径

1. 食物网的结构提供了对生物多样性，有机物（OM）途径和生态系统功能的重要见解。
2. 稳定同位素分析（δ ¹³ C和δ ¹⁵ N）被用来表征营养结构和主OM途径支撑食物网在拉帕努伊沿海海洋生态系统。
3. 估计了消费者在不同营养类别中的营养位置和同位素生态位指标（即中层浮游​​动物，浮游浮游动物，无脊椎动物礁，礁鱼，浮游鱼类和海鸟）。此外，使用贝叶斯混合模型（MixSIAR）对异养消费者评估了不同OM来源（即大型藻类，黄藻类珊瑚和颗粒性OM [POM]）的相对重要性。
4. 结果表明，从小型中上层和底栖无脊椎动物到珊瑚礁和中上层鱼类以及海鸟，有明显的¹³ C和¹⁵ N富集模式。大多数无脊椎动物被分类为主要消费者，礁鱼被分类为次要消费者，中上层捕食者被分类为海鸟，而海鸟被分类为第三级和第四级消费者。
5. 同位素生态位度量表明，与礁动物区系（无脊椎动物和鱼类）相反，远洋鱼类（中游浮游鱼类和远洋鱼类）的营养多样性较低，后者的营养多样性较高，表明开发了更多种类的营养资源。礁无脊椎动物和礁鱼之间的标准椭圆区域重叠表明，这两种组合可能共享营养资源。
6. 混合模型结果表明，POM是中层浮游动物的主要营养途径，是浮游浮游动物的大型藻类（Rhodophyta），并且对于大型底栖动物和礁石无脊椎动物等珊瑚组合而言，珊瑚来源的OM和Rhodophyta是混合的。相比之下，POM的贡献对于营养级别较高的一些中上鱼类和海鸟尤为重要。
7. 这项研究为保护珊瑚礁，管理规划和全面实施最近创建的拉帕努伊多用途海洋保护区提供了关键要素。