Collaborative Research: Climate Change and Upwelling -- Comparative Analysis of Current & Future Responses of the California and Benguela Ecosystems

沿着南北美洲、非洲和伊比利亚半岛的西海岸，沿海岸的赤道风将营养丰富的海水带到阳光普照的海洋表面，刺激浮游植物大量繁殖，支持强健、丰富和多样化的生态系统。这个过程被称为“上升流”。由于上升流是由风驱动的，而风又与大气条件有关，因此上升流极易受到气候变化的影响。然而，气候变化对上升流和生物的潜在影响在很大程度上仍然不确定。在早期对美国西海岸加利福尼亚洋流上升流系统的研究中，研究人员发现，上升流以不同的冬季和夏季“模式”发生，对生物学有不同的影响。在这个项目中，将分析来自南非和纳米比亚外海本格拉洋流系统的海洋学和大气数据，以寻找类似的季节模式及其与生态系统的关系。这两种上升流系统之间的比较将使研究人员能够调查先前关于区域气候对生物学影响的发现是否适用于全球范围，并考虑这些系统在未来可能如何变化。该项目将促进来自南非、纳米比亚和美国的研究人员之间的合作，整合一个由来自所有国家的年轻和资深科学家组成的团队，并为他们提供在职业生涯早期进行大规模科学综合的机会。该项目将对加利福尼亚洋流（CCS）和本格拉洋流（BCS）的气候强迫和生物响应进行比较分析，这两个上升流系统具有最相似的大气和海洋条件时间序列、海鸟种群、低（叶绿素）和中（饲料鱼）营养数据。该项目将确定生态系统的变化是否可以归因于区域或全球气候过程。将开发BCS（深水鳕）鱼类的生长增量年表，作为上层营养鱼类生长的指标，并与CCS中开发的岩鱼生长年表进行比较。中营养水平的鱼类丰度将被建模为综合气候和高营养水平参数的猎物可用性指数。将从全球观测和再分析数据集以及地球系统模式对气候变化的预估中分析海洋学和大气数据。该项目将解决以下问题：1)BCS中季节性上升流模式（冬季和夏季）是否与CCS中一样可识别？2)上升流模式是由相似的或不同的大气强迫机制所强迫的吗？3)在CCS和BCS内部和之间，中营养鱼类、高营养鱼类和海鸟之间是否存在一致性/协方差（以及滞后）的证据？4)在不同的气候变化情景下，导致上升流有利风的大气压力系统的位置和振幅是否会在不同的生态系统之间一致地变化？5)在气候变化中，上升流的季节性和空间分布变化对渔业和野生动物管理的影响是什么？

Along the west coasts of North and South America, Africa, and Iberia, alongshore equatorward winds bring nutrient-rich waters to the sunlit surface of the ocean, stimulating phytoplankton blooms that support robust, rich and diverse ecosystems. This process is known as "upwelling". Because upwelling is driven by winds, and winds are related to atmospheric conditions, upwelling is highly vulnerable to the effects of climate change. However, the potential impacts of climate change on upwelling and biology remain largely uncertain. In earlier work in the California Current upwelling system, off the west coast of the U.S.A, researchers found that upwelling occurs in distinct winter and summer "modes" that have different impacts on biology. In this project, oceanographic and atmospheric data from the Benguela Current system, off South Africa and Namibia, will be analyzed for similar seasonal patterns and relationships with the ecosystem. Comparisons between these two upwelling systems will allow researchers to investigate if previous findings of regional climate impacts on biology are applicable at a global scale and consider how these systems may change in the future. The project will facilitate collaboration between researchers from South Africa, Namibia, and the U.S., integrating a team of young and senior scientists from all countries and providing them with opportunities for broad-scale scientific synthesis early in their careers.This project will be a comparative analyses of climate forcing and biological responses in the California Current (CCS) and Benguela Current systems (BCS), the two upwelling systems with the most similar time series of atmospheric and oceanographic conditions, seabird demography, and lower (chlorophyll) and mid (forage fish) trophic data. The project will determine whether changes in the ecosystems can be attributed to regional or global climate processes. Growth-increment chronologies from fish in the BCS (deep-water hake) will be developed as indicators of upper-trophic fish growth, and compared to rockfish growth chronologies developed in the CCS. Mid-trophic level fish abundance will be modeled as indices of prey availability for integration between climate and upper-trophic-level parameters. Oceanographic and atmospheric data will be analyzed from global observational and reanalysis data sets, as well as from earth system model projections of climate change. The project will address the following questions: 1) are seasonal upwelling modes (winter and summer) discernible in the BCS as they are in the CCS? 2) are upwelling modes forced by similar or contrasting atmospheric forcing mechanisms? 3) is there evidence of coherence/covariance among mid-trophic fish, upper-trophic fish, and seabirds (and at which lags) within and between the CCS and BCS? 4) will the positioning and amplitude of the atmospheric pressure systems that result in upwelling-favorable winds change coherently between ecosystems under various climate-change scenarios? and 5) what are the fisheries and wildlife management implications for variability in the seasonality and spatial distribution of upwelling in a changing climate?