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

美国西海岸外的加利福尼亚洋流系统包括一个沿海上升流区，这是美国专属经济区和世界上最具生产力的海洋生态系统之一。这个上升流区域沿着华盛顿、俄勒冈和加利福尼亚的海岸延伸。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。该地区海洋气候的变化直接或间接地影响着捕捞和受保护的海洋种群，包括许多海洋鱼类、无脊椎动物、海洋哺乳动物和海鸟。由于沿海海洋的高初级生产力以及将碳和其他元素转移到深海水域的过程，加州洋流系统对减少大气中的二氧化碳和碳固存也很重要。在气候变率的来源中，厄尔尼诺Niño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生物，也改变了美国各地的天气模式。2015- 2016年的厄尔尼诺Niño被美国气候预测中心定性为“强”事件，并可能成为近期历史上最强的厄尔尼诺Niños之一。此外，此次厄尔尼诺Niño是在2014年开始的东北太平洋持续异常变暖之后出现的，然后在2015年沿着北美西海岸加剧。预计这两种海洋扰动的结合将在许多方面改变海洋生态系统。这项研究的目的是量化El Niño对海洋食物网底部浮游生物关键过程的影响，因为这些生物的反应是理解和预测El Niño对食物网中更高阶消费者影响的基础。这项研究的更广泛的影响包括提供新的定量理解，这将被纳入未来的厄尔尼诺Niño对美国西海岸影响的预测模型。这种认识的提高将有助于管理重要的海洋生物资源。这项研究将涉及许多海洋科学的研究生，并协助培训下一代海洋科学家。调查人员将与斯克里普斯的伯奇水族馆合作开发公共项目和推广工作，包括“探索浮游生物！”该项目将提高公众对El Niño对沿海远洋社区影响的认识和理解。他们还将制定一个科学探索冒险（SEA）日计划，该计划将重点放在CCE El Niño响应巡航上，以便将游客直接与海洋研究过程和海洋科学事业联系起来。快速响应提案是必要的，因为此El Niño持续时间有限，没有足够的时间通过常规流程提交提案。一个为期20天的研究巡航将在加利福尼亚洋流生态系统的南部地区进行，该地区有一系列广泛的基线测量，可以与厄尔尼诺Niño的影响进行比较。我们将量化El Niño对控制远洋食物网结构和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级生产、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和溶解形式的元素输出。测量方法需要拉格朗日（水包跟踪）研究一系列离散的水包，这些水包代表不同的子区域：近岸沿海上升流区域，近海风应力旋度上升流区域，加利福尼亚洋流的低盐度核心流，以及近海更分层的海洋条件。测量将通过在多个光深的原位孵育、在船上模拟原位孵育以及在每个离散的水包中进行垂直分层取样来完成。这些测量将促进定量预测模型的发展，这些模型可用于预测海洋对未来厄尔尼诺Niños或其他变暖现象的反应。

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.