Ocean and Ecosystem Sciences Division, Bedford Institute of Oceanography, Fisheries and Oceans Canada, P.O. Box 1006, Dartmouth, NS, B2Y 4A2, Canada.
Takuvik International Research Laboratory, Université Laval (Canada) - CNRS (France), Département de biologie et Québec-Océan, Université Laval, Québec, QC, G1V 0A6, Canada.
Nat Commun. 2020 Apr 6;11(1):1705. doi: 10.1038/s41467-020-15485-5.
The Arctic marine biome, shrinking with increasing temperature and receding sea-ice cover, is tightly connected to lower latitudes through the North Atlantic. By flowing northward through the European Arctic Corridor (the main Arctic gateway where 80% of in- and outflow takes place), the North Atlantic Waters transport most of the ocean heat, but also nutrients and planktonic organisms toward the Arctic Ocean. Using satellite-derived altimetry observations, we reveal an increase, up to two-fold, in North Atlantic current surface velocities over the last 24 years. More importantly, we show evidence that the North Atlantic current and its variability shape the spatial distribution of the coccolithophore Emiliania huxleyi (Ehux), a tracer for temperate ecosystems. We further demonstrate that bio-advection, rather than water temperature as previously assumed, is a major mechanism responsible for the recent poleward intrusions of southern species like Ehux. Our findings confirm the biological and physical "Atlantification" of the Arctic Ocean with potential alterations of the Arctic marine food web and biogeochemical cycles.
随着温度升高和海冰覆盖范围缩小，北极海洋生物群系正在与低纬度地区紧密相连，这种联系主要通过北大西洋来实现。北大西洋水流通过欧洲北极走廊向北流动（80%的进出流都发生在这个主要的北极门户），将大部分海洋热量、营养物质和浮游生物输送到北冰洋。利用卫星衍生的测高观测，我们揭示了过去 24 年来北大西洋表层流速度增加了一倍。更重要的是，我们的研究结果表明，北大西洋水流及其变化是甲藻（Emiliania huxleyi，Ehux）空间分布的形成因素，Ehux 是温带生态系统的示踪剂。我们进一步证明，生物输送，而不是以前假设的水温，是最近南方物种如 Ehux 向极地方向入侵的主要机制。我们的研究结果证实了北冰洋的生物和物理“大西洋化”，这可能会改变北极海洋食物网和生物地球化学循环。
