There is growing evidence that increased Pacific water transport into the Arctic affects the marine ecosystem. One of the theoretical predictions for a future Arctic characterized by such environmental change is that subarctic taxa will expand northward and invade the native Arctic ecosystem. This study focuses on variation in macrofaunal community composition and the influence of changing physical drivers at known benthic hotspots in the Pacific Arctic. The average number of macrofaunal family-level taxa has increased significantly south of St. Lawrence Island and in the Chirikov Basin, whereas the number of macrofaunal taxa in the southeastern Chukchi Sea showed no significant trend over the 2000–2013 time period. However, the Shannon–Weaver diversity index, based on abundance, did not mirror these regional changes in the number of macrofaunal taxa, indicating that the abundance of newly present taxa was negligible compared to the entire abundance already present. We also investigated temporal variations in meridional sea level gradient and local winds, which contribute 2/3 and 1/3 of the variation in northward volume transport at Bering Strait, respectively. There were significant increasing trends in the meridional sea level gradient and local winds, suggesting the increased northward seawater volume transports over the benthic hotspots could contribute to the expansion of subarctic taxa into these northern Arctic regions. Our data suggest an increase in macrofaunal taxa type with increasing current transport northward into the Pacific Arctic region that could have a strong influence in restructuring the benthic ecosystem in this region in the future.

中文翻译：

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与太平洋北极地区物理强迫相关的底​​栖大型动物群落组成的最新变化

越来越多的证据表明，进入北极的太平洋水运增加会影响海洋生态系统。对以这种环境变化为特征的未来北极的理论预测之一是亚北极分类群将向北扩展并侵入北极本土生态系统。这项研究的重点是大型动物群落组成的变化以及太平洋北极已知底栖热点的物理驱动因素变化的影响。圣劳伦斯岛以南和奇里科夫盆地的大型动物家庭级分类群的平均数量显着增加，而楚科奇海东南部的大型动物分类群的数量在 2000-2013 年期间没有显着趋势。然而，基于丰度的香农-韦弗多样性指数，没有反映大型动物分类群数量的这些区域变化，这表明与已经存在的整个丰度相比，新出现的分类群的丰度可以忽略不计。我们还研究了经向海平面梯度和局地风的时间变化，它们分别贡献了白令海峡向北体积运输变化的 2/3 和 1/3。经向海平面梯度和局地风有显着增加的趋势，表明底栖热点向北的海水量传输增加可能有助于亚北极分类群向这些北极北部地区扩张。