RAPID: Responses of the California Current Ecosystem to El Nino 2015-16

美国西海岸外的加利福尼亚州海流系统包括一个沿海上升区，该地区是美国专属经济区和世界上生产力最高的海洋生态系统之一。这片上升区沿着华盛顿、俄勒冈和加利福尼亚州的海岸延伸。该地区开发了许多海洋生物资源，其中包括五个国家海洋保护区。该区域海洋气候的变化直接和间接地影响到捕捞的和受保护的海洋种群，包括多种海洋鱼类、无脊椎动物、海洋哺乳动物和海鸟。由于沿海海洋的初级生产力很高，以及将碳和其他元素转移到深海水域的过程，加州海流系统对大气二氧化碳的减少和碳封存也很重要。在气候多变性的来源中，厄尔尼诺被认为是地球上最大的气候信号。它显著地影响了许多海洋种群，并改变了美国各地的天气模式。目前的2015-16年厄尔尼诺现象已被美国气候预测中心定性为“强”事件，并可能成为近代史上最强的厄尔尼诺现象之一。此外，这次厄尔尼诺现象发生之前，东北太平洋从2014年开始出现持续的异常变暖，并于2015年在北美西海岸加剧。这两种海洋扰动的结合预计将在许多方面改变海洋生态系统。拟议研究的目的是量化厄尔尼诺对作用于海洋食物网底部浮游生物的关键过程的影响，因为这些生物的反应对于理解和预测厄尔尼诺对食物网中高级消费者的影响至关重要。这项研究的更广泛影响包括提供新的量化理解，这些理解将被纳入未来美国西海岸厄尔尼诺效应的预测模型。这一认识的提高将有助于关键海洋生物资源的管理。这项研究将涉及许多海洋科学方面的研究生，并帮助培训下一代海洋科学家。调查人员将与斯克里普斯的白桦水族馆合作开发公共项目和外展工作，包括探索它：浮游生物！将提高公众对厄尔尼诺现象对沿海远洋社区影响的认识和了解的公共方案。他们还将制定科学探索探险(SEA)日计划，重点放在CCE厄尔尼诺响应邮轮上，以便将游客直接联系到海洋研究过程和海洋科学职业。快速响应建议是必要的，因为这次厄尔尼诺现象的持续时间有限，没有足够的时间通过常规程序提交建议。将在加利福尼亚州当前生态系统的南部进行为期20天的研究巡航，该地区有一系列广泛的基线测量，可以与厄尔尼诺现象的影响进行比较。我们将量化厄尔尼诺现象对控制远洋食物网结构和控制元素循环速率的关键速率过程的影响。测量的过程将包括初级和次生生产、放牧、溶解铁对浮游植物生长的影响、碳和氮的循环以及颗粒物和溶解形式的元素出口。测量方法需要对代表不同分区的一系列离散水块进行拉格朗日(水包跟踪)研究：近岸沿海上升区、离岸风应力卷曲上升区、加利福尼亚州海流本身的低盐度核心流，以及近海更分层的海洋条件。测量将通过多个光照深度的现场培养、船上模拟的现场培养以及每个离散水域的垂直分层采样进行。这些测量将有助于开发可用于预测海洋对未来厄尔尼诺现象和可能其他变暖现象的反应的定量预测模型。

The California Current System off the U.S. west coast includes a coastal upwelling region that is among the most productive ocean ecosystems within the U.S. Exclusive Economic Zone, and the world. This upwelling domain extends along the coasts of Washington, Oregon, and California. Many living marine resources develop in this region, which includes five National Marine Sanctuaries. Variability in ocean climate in this region directly and indirectly influences both harvested and protected marine populations, including numerous species of marine fishes, invertebrates, marine mammals, and seabirds. The California Current System is also important to drawdown of atmospheric carbon dioxide and carbon sequestration, due to the high primary productivity of the coastal ocean and processes that transfer carbon and other elements into deep ocean waters. Of sources of climate variability, El Niño is considered the largest climate signal on earth. It markedly influences many ocean populations, as well as modifying weather patterns across the United States. The current El Niño of 2015-16 has been characterized as a "strong" event by the U.S. Climate Prediction Center, and may become one of the strongest El Niños in recent history. In addition, this El Niño follows a sustained, unusual warming in the Northeast Pacific Ocean that began in 2014, and then intensified along the west coast of North America in 2015. The combination of these two ocean perturbations is expected to alter marine ecosystems in many ways. The purpose of the proposed research is to quantify the effects of El Niño on key processes acting on planktonic organisms at the base of the ocean food web, because responses of these organisms are fundamental to understanding and forecasting the effects of El Niño on higher order consumers in the food web. The Broader Impacts of this research include the provision of new quantitative understanding that will be incorporated into future forecast models of the effects of El Niño off the U.S. west coast. This improved understanding will aid in the management of key living marine resources. The research will involve numerous graduate students in at-sea science and aid in the training of the next generation of ocean scientists. The investigators will develop public programs and outreach efforts in collaboration with the Birch Aquarium at Scripps, including an Explore-It: Plankton! public program that will increase public awareness and understanding of El Niño effects on coastal pelagic communities. They will also develop a Science Exploration Adventure (SEA) Days program that will focus on the CCE El Niño response cruise, in order to connect visitors directly to the process of ocean research and careers in the ocean sciences. A RAPID response proposal is necessary because this El Niño will be of limited duration and there is insufficient time to submit a proposal through the regular process.A 20-day research cruise will be conducted in the southern sector of the California Current Ecosystem, a region with an extensive series of baseline measurements against which the effects of El Niño can be compared. We will quantify the effects of El Niño on key rate processes that control the structure of the pelagic food web and control rates of elemental cycling. The processes measured will include primary and secondary production, grazing, dissolved iron effects on phytoplankton growth, carbon and nitrogen recycling, and elemental export in both particulate and dissolved forms. The measurement approach entails a Lagrangian (water parcel-tracking) study of a series of discrete water parcels that represent different subregions: the nearshore coastal upwelling region, the offshore wind-stress curl upwelling domain, the low salinity core flow of the California Current proper, and more stratified ocean conditions offshore. Measurements will be done by in situ incubations at multiple light depths, by simulated in situ incubations aboard ship, and by vertically stratified sampling in each discrete water parcel. These measurements will facilitate the development of quantitative forecast models that can be used to project ocean responses to future El Niños and perhaps other warming phenomena.