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

合作研究：气候变化与上升流——当前的比较分析

• 批准号: 1434530
• 负责人: Ryan Rykaczewski
• 金额: $ 14.99万
• 依托单位: University of South Carolina at Columbia
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1434530&HistoricalAwards=false
• 关键词: Collaborative; Research; Climate; Change; Upwelling

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?

沿着南北美洲、非洲和伊比利亚的西海岸，沿岸的赤道风将营养丰富的沃茨带到阳光照射的海洋表面，刺激浮游植物大量繁殖，从而支撑起强健、丰富和多样的生态系统。 这个过程被称为“上升流”。 由于上升流是由风驱动的，而风与大气条件有关，因此上升流非常容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。 在美国西海岸附近的加州洋流上升流系统的早期工作中，研究人员发现上升流发生在不同的冬季和夏季“模式”中，对生物学有不同的影响。 在本项目中，将分析南非和纳米比亚近海本格拉海流系统的海洋学和大气数据，以了解类似的季节模式和与生态系统的关系。 这两个上升流系统之间的比较将使研究人员能够调查以前关于区域气候对生物影响的研究结果是否适用于全球范围，并考虑这些系统未来可能如何变化。 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，该项目将对加州海流（CCS）和本格拉海流（BCS）的气候强迫和生物反应进行比较分析，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，海鸟数量，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归因于区域或全球气候过程。 将制定BCS（深水无须鳕）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中制定的岩鱼生长年表进行比较。 中营养级鱼类丰度将被建模为气候和高营养级参数之间的整合的猎物可用性指数。 海洋和大气数据将从全球观测和再分析数据集以及地球系统模型对气候变化的预测中进行分析。 该项目将解决以下问题：1）在BCS中的季节性上升流模式（冬季和夏季）是否与CCS中一样明显？2)上升流模式是由相似或相反的大气强迫机制所强迫的吗？3)在CCS和BCS之内和之间，是否有证据表明中营养鱼类、高营养鱼类和海鸟之间存在一致性/协变性（以及滞后时间）？4)在各种气候变化情景下，导致有利于上升的风的大气压力系统的位置和幅度是否会在生态系统之间发生一致变化？以及5）在气候变化中，上升流的季节性和空间分布的变化对渔业和野生动物管理有何影响？