Sustainability and Data Sciences Laboratory, Department of Civil and Environmental Engineering, Northeastern University, Boston, Massachusetts 02115, USA.
Department of Marine and Environmental Sciences, Marine Science Center, Northeastern University, Nahant, Massachusetts 01908, USA.
Nature. 2015 Feb 19;518(7539):390-4. doi: 10.1038/nature14235.
The timing and strength of wind-driven coastal upwelling along the eastern margins of major ocean basins regulate the productivity of critical fisheries and marine ecosystems by bringing deep and nutrient-rich waters to the sunlit surface, where photosynthesis can occur. How coastal upwelling regimes might change in a warming climate is therefore a question of vital importance. Although enhanced land-ocean differential heating due to greenhouse warming has been proposed to intensify coastal upwelling by strengthening alongshore winds, analyses of observations and previous climate models have provided little consensus on historical and projected trends in coastal upwelling. Here we show that there are strong and consistent changes in the timing, intensity and spatial heterogeneity of coastal upwelling in response to future warming in most Eastern Boundary Upwelling Systems (EBUSs). An ensemble of climate models shows that by the end of the twenty-first century the upwelling season will start earlier, end later and become more intense at high but not low latitudes. This projected increase in upwelling intensity and duration at high latitudes will result in a substantial reduction of the existing latitudinal variation in coastal upwelling. These patterns are consistent across three of the four EBUSs (Canary, Benguela and Humboldt, but not California). The lack of upwelling intensification and greater uncertainty associated with the California EBUS may reflect regional controls associated with the atmospheric response to climate change. Given the strong linkages between upwelling and marine ecosystems, the projected changes in the intensity, timing and spatial structure of coastal upwelling may influence the geographical distribution of marine biodiversity.
主要大洋东缘风生沿海上升流的时间和强度通过将深层富营养水带到阳光充足的表面，从而调节关键渔业和海洋生态系统的生产力，在那里可以进行光合作用。因此，沿海上升流在变暖气候下可能会发生怎样的变化是一个至关重要的问题。尽管由于温室变暖导致的陆海温差增强被提议通过加强沿岸风来加剧沿海上升流，但对观测和先前气候模型的分析对沿海上升流的历史和预测趋势几乎没有达成共识。在这里，我们表明，大多数东边界上升流系统（EBUS）对未来变暖的响应，在时间、强度和空间异质性方面都发生了强烈而一致的变化。气候模型的集合表明，到二十一世纪末，上升流季节将提前开始，推迟结束，在高纬度地区变得更加剧烈，但在低纬度地区则不然。这种在高纬度地区上升流强度和持续时间的预计增加将导致现有的沿海上升流纬度变化大幅减少。这一模式在四个 EBUS 中的三个（加那利群岛、本格拉和洪堡，但不是加利福尼亚）中是一致的。加利福尼亚 EBUS 缺乏上升流增强和更大的不确定性可能反映了与气候变化大气响应有关的区域控制。鉴于上升流与海洋生态系统之间的紧密联系，沿海上升流的强度、时间和空间结构的预计变化可能会影响海洋生物多样性的地理分布。
