Authors: Nicolas Lubitz, Ryan Daly, Amy F. Smoothey, Patrick Vianello, Michael J. Roberts, David S. Schoeman, Marcus Sheaves, Paul D. Cowley, Laurent Dagorn, Fabien G. Forget, Marc Soria, Victor M. Peddemors, John D. Filmalter, Paul A. Butcher, Greg Brett, and Adam Barnett
Journal: Nature Climate Change
The impacts on marine species from secular warming and heatwaves are well demonstrated; however, the impacts of extreme cold events are poorly understood. Here we link the death of organisms from 81 species to an intense cold upwelling event in the Agulhas Current, and show trends of increasing frequency and intensification of upwelling in the Agulhas Current and East Australian Current. Using electronic tagging, we illustrate the potential impacts of upwelling events on the movement behaviour of bull sharks Carcharhinus leucas, including alterations of migratory patterns and maintenance of shallower dive profiles when transiting through upwelling cells. Increasing upwelling could result in ‘bait and switch’ situations, where climate change expands subtropical species’ distribution, while simultaneously exposing climate migrants to an increased risk of cold-mortality events at poleward distributional limits. This shows the potential impacts of increased cold events, an understudied aspect of climate change research, and highlights the complexities of climate change effects on marine ecosystems.
长期变暖和热浪对海洋物种的影响已得到充分证明；然而，极端低温事件的影响却鲜为人知。本文将81个物种的生物死亡与阿古拉斯海流中一次较强的冷上升流事件联系起来，并展示了阿古拉斯海流和东澳大利亚洋流中上升流频率增加和强度增大的趋势。通过使用电子监控，本文展示了上升流事件对公牛真鲨运动行为的潜在影响，包括改变其迁徙模式和在通过上升流区域时保持较浅的潜水深度。上升流的增加可能导致“诱导转向”现象，即气候变化扩大了亚热带物种的分布范围，同时也使其在向极分布的极限地带面临更大的“冷致死“事件风险。本文展示了低温事件增加的潜在影响，这是气候变化研究中一个尚未得到充分研究的方面，并强调了气候变化对海洋生态系统影响的复杂性。
（实习生张郑颖编译）
