History and future of coastal upwelling modes and biological responses in the California Current

气候在多个时间尺度上的变异性日益被认为是影响加州当前生态系统(CCE)结构、功能和生产力的一个主要因素。然而，尽管进行了许多长期和综合的研究，但对气候对上升流和生物过程的影响仍然缺乏详细的了解，这损害了我们评估重要概念的能力，如生态系统“健康”和“恢复能力”。为了解决CCE中北部的这些问题，私人投资机构最近整理和分析了岩鱼和鲑鱼生长以及海鸟繁殖成功与上升流变化有关的记录(国家科学基金会奖#0929017)。这些不同的、多年代际的时间序列揭示了冬季上升流对生态系统结构和功能的重要性，尽管上升流是CCE生产力的主要驱动因素，主要是夏季过程。这项研究导致了一个意想不到的发现，冬季和夏季的上升流以不同的季节性“模式”相互独立地变化，一些生物过程受冬季模式的影响，另一些生物过程受夏季模式的影响。这一点很重要，因为夏季模式显示长期增加(尽管有年代际变化)，而冬季模式则不是。智力价值：在这个新的项目中，PI将测试最重要的假设，即上升流模式是由不同的大气-海洋过程迫使的，显示出低频和高频变化的对比模式，并将受到全球气候变化的不同影响，以及对生物的相应影响。为了解决这一假设，PI提出了一个三层方法，以更好地理解季节性上升流模式及其对CCE生物学的不同影响。首先，他们将研究一套全新的物种对上升流模式的反应，包括太平洋沙丁鱼(补充)、黑岩鱼(生长)、犀牛奥克利特和勃兰特隼(生存)，以及Coho鲑鱼(生存)。以前，这些分析使用的是粗略解析的上升流指数，但现在PIS将整合来自当地浮标数据的风和温度，以更好地在更精细的时间尺度上捕捉气候变化。其次，他们将对季节性上升流模式产生更机械的理解，并将这些信息与全球气候模型结合使用，以预测各种气候变化情景下的上升流反应。第三，初步结果表明，树木年轮数据与鱼类和海鸟共同变化，对冬季上升流的驱动因素北方涛动指数(NOI)也同样敏感。PIS将使用树木年轮数据来提供300-400年冬季NOI的重建，以评估上升流平均和方差的历史变化范围。这项研究将揭示加州海流上升流的过去、现在和潜在的未来及其生物后果。广泛的影响：这项研究将探索独立的季节性气候模式的历史、未来和生物影响及其对关键物种的影响。在这样做的过程中，PIs将发展对气候-生态系统耦合变化的理解，这将有助于州、国家和国际政策制定者，包括加州合作气候适应小组(CO-CAT)和IPCC评估报告5。PIs将开发和测试加州当前生态系统生产力的生物和物理指标，并将这些信息提供给管理，特别是渔业种群和综合生态系统评估。该项目将为2名博士后助理研究员、2名其他青年科学家和1名本科生提供物理海洋学、海洋生态学、量化技能、交流以及项目和财务管理和筹资等科学业务方面的交叉培训。

Climate variability on multiple temporal scales is increasingly recognized as a major factor influencing the structure, functioning, and productivity of the California Current Ecosystem (CCE). Yet, despite many long-term and integrative studies, a detailed understanding of climatic impacts on upwelling and biological processes is still lacking, compromising our abilities to assess important concepts such as ecosystem "health" and "resilience." To address these issues in the central-northern CCE, the PIs have recently collated and analyzed records of rockfish and salmon growth and seabird reproductive success with respect to upwelling variability (NSF award #0929017). These diverse, multi-decadal time series revealed the importance of wintertime upwelling on ecosystem structure and function, even though upwelling, a principal driver of productivity in the CCE, is largely a summertime process. This research led to an unexpected discovery that winter and summer upwelling vary independently of one another in distinct seasonal "modes", with some biological processes affected by the winter mode and others by the summer mode. This is of significance because the summer mode shows a long-term increase (despite inter-decadal variability) while the winter mode does not. Intellectual Merit: In this new project, the PIs will test the overarching hypothesis that upwelling modes are forced by contrasting atmospheric-oceanographic processes, exhibit contrasting patterns of low- and high-frequency variability, and will be differentially impacted by global climate change with corresponding impacts on biology. To address this hypothesis the PIs propose a three-tiered approach to better understand seasonal upwelling modes and their differential impacts on biology of the CCE. First, they will examine the responses of an entirely new suite of species to upwelling modes, including Pacific sardine (recruitment), black rockfish (growth), rhinoceros auklet and Brandt's cormorant (survival), and coho salmon (survival). Previously, coarsely resolved upwelling indices were used in these analyses, but the PIs now will integrate winds and temperatures from local buoy data to better capture climate variability on finer timescales. Second, they will derive a more mechanistic understanding of seasonal upwelling modes and use this information in combination with global climate models to forecast upwelling responses under various climate-change scenarios. Third, preliminary results indicate that tree-ring data co-vary with the fish and seabirds and are similarly sensitive to a driver of winter upwelling, the Northern Oscillation Index (NOI). The PIs will use tree-ring data to provide a 300-400 year reconstruction of the winter NOI to assess the historical range of variability in upwelling mean and variance. This study will reveal the past, present forcing, and potential future of upwelling and its biological consequences in the California Current.Broader Impacts: This study will explore the history, future, and biological impacts of independent, seasonal climate modes and their impacts on key species. In so doing, the PIs will develop an understanding of coupled climate-ecosystem change that will be contributed to state, national, and international policy-makers, including the California Cooperative Climate Adaptation Team (CO-CAT)and the IPCC Assessment Report 5. The PIs will develop and test biological and physical indicators of California Current ecosystem productivity and will make this information available for management, specifically fisheries stock and integrated ecosystem assessments. The project will provide cross-training for 2 post-doctoral research associates, 2 other young scientists, and 1 undergraduate in physical oceanography, marine ecology, quantitative skills, communication, as well as the business of science, such as project and fiscal management and fund-raising.