Collaborative Research: Assessing the causes of the pyrosome invasion and persistence in the California Current Ecosystem

海洋食物网的一个关键组成部分是由浮游动物或浮游动物组成的，它们将能量从浮游植物转移到鱼类、鲸鱼和鸟类。浮游动物包括许多不同类型的生物，可大致归类为甲壳类或胶状动物，大多数鱼类和鲸鱼更喜欢将甲壳类动物作为富含脂肪的食物来源，而不是水分含量较高的胶状动物。从历史上看，美国西海岸外的加州目前的生态系统一直由甲壳类浮游动物主导，如磷虾和桡足类，但在2014年，有大量的聚集性、胶状浮游动物被称为火焰体，这对渔业造成了广泛的破坏，因为它污染了渔具，并控制了捕获量。尽管火焰体的到来与大范围的海洋热浪不谋而合，但自那以来，尽管海洋温度恢复到较低的水平，但火焰体的丰度一直较低。对加州合作海洋渔业调查(CalCOFI)的时间序列数据的分析表明，几十年前在海洋还不是特别温暖的时候，也在加州洋流中观察到了灼热体。这项研究结合了对CalCOFI过去样本的分析、海洋环流模型和生物模型，以了解加州洋流中这些快速增长的火小体种群的原因。它支持对本科生和研究生的培训。此外，该项目通过与圣地亚哥县教育办公室的独特合作伙伴关系接触到K-12学生，该办公室正在为加利福尼亚州的初中和高中科学教师开发与下一代科学标准(NGSS)一致的资源。这些教育资源正在通过加州科学项目和加州环境扫盲倡议进行传播。圣地亚哥(加利福尼亚州)的公众宣传活动是通过国家海洋科学碗的增强您的地平线圣地亚哥会议和圣地亚哥地区竞赛进行的，圣克鲁斯(加利福尼亚州)通过西摩海洋探索中心进行的。最近在加利福尼亚州洋流中出现的火胞菌是对生态系统的一次重大扰动，原因尚不清楚。海洋物理和浮游生物食物网动态都是该生态系统中上层群落组成可变性的关键决定因素，然而，揭示物理可变性(通过变暖和平流)与变化的生物相互作用(通过营养循环和改变的食物网动态)相结合以确定组成和功能的程度是复杂的。该项目结合了对CalCOFI时间序列过去70年历史样本的分析，数据同化和非数据同化海洋环流模型，以及生物种群模型，以确定海洋物理和生物相互作用在塑造加州洋流中火焰体丰度、营养动态以及种群增长和死亡方面所起的作用。这一新颖的框架提供了预测浮游生物群落如何应对气候变化所需的机械理解。物理海洋学计划为该奖项提供了资金。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

A key component of the ocean food web is comprised of floating animals, or zooplankton, that transfer energy from phytoplankton to fish, whales, and birds. Zooplankton include many different types of organisms that can be broadly categorized as crustacean or gelatinous, with most fish and whales preferring crustaceans as a fat-rich food source over gelatinous animals, which are higher in water content. Historically, the California Current ecosystem off the U.S. West Coast has been dominated by crustacean zooplankton, such as krill and copepods, but in 2014 there were huge abundances of a type of colonial, gelatinous zooplankton known as pyrosomes, which caused widespread damage to fisheries by fouling fishing gear and dominating catch. Although the arrival of pyrosomes coincided with an extensive marine heatwave, lower abundances have since persisted despite a return to cooler ocean temperatures. Analysis of time series data from the California Cooperative Oceanic Fisheries Investigations (CalCOFI) indicate that pyrosomes were also observed in the California Current many decades ago when the ocean was not particularly warm. This study combines analysis of past samples from CalCOFI, ocean circulation models, and biological models to understand the causes of these quickly growing pyrosome populations in the California Current. It supports training for undergraduate and graduate students. In addition, the project is reaching K-12 students through a unique partnership with the San Diego County Office of Education that is developing Next Generation Science Standards (NGSS)-aligned resources for middle and high school science teachers in California. The educational resources are being disseminated through the California Science Project and California Environmental Literacy Initiative. Public outreach in San Diego (CA) is through the Enhancing Your Horizons San Diego conference and the San Diego Regional Competition of the National Ocean Sciences Bowl, and in Santa Cruz (CA) through the Seymour Marine Discovery Center.Predicting how ecosystems respond to accelerating climate change is a major challenge. The recent appearance of the pyrosome Pyrosoma atlanticum in the California Current is a major perturbation to the ecosystem, and the cause remains unknown. Both ocean physics and plankton food-web dynamics are key determinants of variability in pelagic community composition in this ecosystem, yet unraveling the degree to which variability in physics (through warming and advection) combines with shifting biological interactions (through nutrient cycling and altered food-web dynamics) to determine composition and function is complicated. This project combines the analysis of past historical samples from seven decades of the CalCOFI time series, data-assimilative and non-data assimilative ocean circulation models, and biological population models to determine the role ocean physics and biological interactions have played in shaping pyrosome abundance, trophic dynamics, and population growth and mortality in the California Current. This novel framework is providing mechanistic understanding that is required to predict how plankton communities respond to climate change.The Physical Oceanography Program contributed funding for this award.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.