Abstract Gelatinous zooplankton (GZ), here understood as pelagic cnidarians and ctenophores, are an important component of marine ecosystems. Their diversity and distribution reflect local hydrological settings especially well, thus allowing the development of biotic indices for studying climate-mediated changes in the world’s oceans. The effects of global warming are most pronounced in the Arctic Ocean and have been further accelerated by the strengthening inflow of relatively warm Atlantic waters (AtW) via the Fram Strait, referred to as Atlantification. Here, we use the GZ distribution to describe the current state of Atlantic water inflow into the Arctic Ocean and to discuss the future of this fragile ecosystem. For this purpose, we characterized the abundance, diversity, and demography of the GZ identified from vertically stratified samples (down to 1000 m) collected in the Fram Strait along two latitudinally parallel transects of varying influence of AtW. Overall, we identified 17 taxa, with Aglantha digitale, Dimophyes arctica and Mertensia ovum being the most abundant. We then contrasted our jellyfish and ctenophore data with both biotic and environmental ecosystem characteristics and analysed the associations between the GZ community and water mass distribution. We showed that the more abundant GZ community was found along the southern transect; that the sampling depth and bathymetric zone played the most important roles in structuring the GZ diversity; that water mass distribution affected GZ demography; and that AtW was dominated by A. digitale, that constituted 66% of the total GZ abundance. Our results, although temporarily limited, suggest that the Atlantification will promote the expansion of boreal species into the Arctic, and could lead to a less diverse, but more abundant GZ community in the future. In addition, we compare in detail the GZ community found in different water masses, at different depths, and in different bathymetric zones, and supported with literature data, discuss the future of the European Arctic under the scenario of increasing inflow of Atlantic water.

中文翻译：

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弗拉姆海峡（北冰洋）凝胶状浮游动物垂直分布和多样性中大西洋化的足迹

摘要 胶状浮游动物（GZ），这里被理解为中上层刺胞动物和栉水母，是海洋生态系统的重要组成部分。它们的多样性和分布特别好地反映了当地的水文环境，从而可以开发用于研究世界海洋中气候介导的变化的生物指数。全球变暖的影响在北冰洋最为显着，并且通过弗拉姆海峡的相对温暖的大西洋水域 (AtW) 的流入加强，被称为大西洋化，进一步加速了全球变暖的影响。在这里，我们使用 GZ 分布来描述大西洋流入北冰洋的水的现状，并讨论这个脆弱生态系统的未来。为此，我们描述了丰富性、多样性、从垂直分层样本（低至 1000 米）中沿两个受 AtW 影响不同的横向平行横断面收集到的 GZ 和人口统计数据。总体而言，我们确定了 17 个分类群，其中最丰富的是洋地黄、北极狐球藻和卵子鼠尾草。然后，我们将我们的水母和栉水母数据与生物和环境生态系统特征进行了对比，并分析了 GZ 群落与水体分布之间的关联。我们表明，沿南部样带发现了更丰富的 GZ 群落；采样深度和测深带在构建 GZ 多样性中起着最重要的作用；水体分布影响了广州市人口；并且 AtW 以 A. digitale 为主，占 GZ 总丰度的 66%。我们的结果，尽管暂时受到限制，但表明大西洋化将促进北方物种向北极扩张，并可能导致未来广州群落的多样性减少但更加丰富。此外，我们详细比较了在不同水团、不同深度和不同测深带中发现的GZ群落，并以文献数据为支撑，讨论了大西洋水流入增加的情景下欧洲北极的未来。