Understanding the structure and functioning of marine ecosystems has become a critical issue to assess the potential shortand long-term effects of natural and anthropogenic impacts and to determine the knowledge needed to conduct appropriate conservation actions. This goal can be achieved in part by acquiring more detailed food web information and evaluating the processes that shape food web structure and dynamics. Our main objective was to identify largescale patterns in the organization of pelagic food webs that can be linked to a wasp-waist (WW) structure, proposed for the southwestern South Atlantic Ocean. We evaluated 3 sub-Antarctic marine areas in a regional context: the Beagle Channel (BC), the Atlantic coast of Tierra del Fuego (CA) and the oceanic Burdwood Bank area (BB). We used carbon and nitrogen isotopic information of all functional trophic groups, ranging from primary producers to top predators, and analyzed them through stable isotope-based Bayesian analyses. We found that BC and BB have a more pronounced WW structure compared to CA. We identified species at mid to low trophic positions that play a key role in the trophodynamics of each marine area (e.g. Fuegian sprat Sprattus fuegensis, longtail southern cod Pata go no tothen ramsayi and squat lobster Munida gregaria) and considered them as the most plausible WW species. The identification of the most influential species within food webs has become a crucial task for conservation purposes in local and regional contexts to maintain eco system integrity and the supply of ecosystem services for the southwestern South Atlantic Ocean. OPEN ACCESS The Southwestern Atlantic Ocean has a large number of species linked by an intermediate trophic level with a few biological components of ecological importance. Image: Luciana Riccialdelli

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南部海洋生态系统的营养结构：黄蜂腰假设下从比格尔海峡到海洋伯德伍德银行地区的同位素比较分析

了解海洋生态系统的结构和功能已成为评估自然和人为影响的潜在短期和长期影响以及确定开展适当保护行动所需知识的关键问题。这一目标可以通过获取更详细的食物网信息和评估塑造食物网结构和动态的过程来部分实现。我们的主要目标是确定远洋食物网组织中的大规模模式，这些模式可以与为南大西洋西南部提出的黄蜂腰 (WW) 结构相关联。我们在区域范围内评估了 3 个亚南极海域：比格尔海峡 (BC)、火地岛大西洋沿岸 (CA) 和伯德伍德海岸 (BB)。我们使用了从初级生产者到顶级捕食者的所有功能性营养组的碳和氮同位素信息，并通过基于稳定同位素的贝叶斯分析对其进行了分析。我们发现与 CA 相比，BC 和 BB 具有更明显的 WW 结构。我们确定了中低营养位置的物种，这些物种在每个海洋区域的营养动力学中起关键作用（例如 Fuegian sprat Sprattus fuegensis、长尾南部鳕鱼 Pata go no tothen ramsayi 和蹲龙虾 Munida gregaria），并认为它们是最合理的 WW物种。确定食物网中最具影响力的物种已成为当地和区域环境中保护目的的一项关键任务，以保持生态系统完整性和南大西洋西南部的生态系统服务供应。开放通道 西南大西洋有大量物种，它们通过中等营养水平与少数具有生态重要性的生物成分联系在一起。图片：Luciana Riccialdelli