Long-Term Changes in California Current Zooplankton Assemblages: A Retrospective Analysis

摘要：海洋浮游动物是物理气候信号传播给海洋鱼类种群的主要途径之一。现在有证据表明，浮游动物生物量在地理上的广泛变化与东北太平洋大气和海洋环流的变化相一致。然而，这种对大量浮游动物生物量的分析没有区分具有不同生活史的分类群，其中一些是浮游生物鱼类的重要营养联系，而另一些则不是。浮游动物的种类组成可以强烈地影响浮游动物与鱼类联系的强度，从而改变招募的成功率。对气候与浮游鱼类联系的机制理解和定量建模将取决于对浮游动物动物群的具体了解，以及不同浮游动物类群对东北太平洋环流和生产力变化的差异反应。我们建议对过去43年/年的加州电流系统（CCS）进行回顾性分析。我们将利用高质量的CalCOFI浮游动物数据，连同相关的水文数据和大气强迫指数，来了解1951年至今浮游动物变化的原因。研究浮游动物组成的三个方面：所有全浮游动物类群（包括胶状和甲壳类）的高级分类组成的变化；桡足类物种组成的变化及其他分类群的选择以及两种颗粒放牧桡足类的营养结构和氮经济变化。我们假设对东北太平洋气候的年代际变化（包括1976年的变暖事件）有不同的、特定的分类单元响应。厄尔尼诺现象和其他赤道地区和亚北极太平洋的年际变化。沿海上升流和跨岸运输强度的区域差异。我们的研究将首次提供对太平洋浮游动物物种多年代际变化的理解。我们将发现导致CCS浮游动物生物量长期下降70%的分类群。我们将建立CCS中南部区域种群变化的时间一致性，并以此分析其与亚北极太平洋相关浮游动物物种的共变。这些研究将成为设计新的GLOBEC实地研究和发展东北太平洋远洋生态系统模式的基础。

Title: Long term Changes in California Current Zooplankton A Retrospective Analysis Project Summary: Marine zooplankton are one of the primary pathways through which physical climate signals propagate to marine fish populations. Evidence now shows geographically extensive changes of zooplankton biomass in concert with variations in the atmospheric and oceanic circulation in the NE Pacific. However, such analyses of bulk zooplankton biomass do not distinguish among taxa with diverse life histories, some of which are important trophic links to planktivorous fishes and others of which are not. The species composition of the zooplankton can strongly influence the intensity of zooplankton fish linkages, and consequently alter recruitment success. Mechanistic understanding and quantitative modeling of climate linkages to planktivorous fishes will depend upon specific knowledge of the zooplankton fauna and the differential responses of different zooplankton taxa to variations in circulation and productivity of the NE Pacific. We propose a retrospective analysis of the past 43/a decades of the California Current System (CCS). We will use the high quality CalCOFI zooplankton collection, together with associated hydrographic data and indices of atmospheric forcing, to understand the causes of changes in the zooplankton from 1951 to the present. Three aspects of the zooplankton composition will be investigated: changes in the high level taxonomic composition of all holozooplankton taxa, including gelatinous and crustacean forms; changes in the species composition of copepods and selected other taxa; and changes in trophic structure and nitrogen economy as inferred from the N stable isotope composition of two species of particlegrazing copepods. We hypothesize that there have been differential, taxon specific responses to: ª Decadal scale changes in the climate of the NE Pacific, including the 1976 77 warming event. . El Nifio and other interannual variations in flow from the equatorial region and from the Subarctic Pacific. Regional differences in the intensity of coastal upwelling and cross shore transport. Our studies will provide, for the first time, an understanding of multi decadal zooplankton species changes in the Pacific. We will uncover the taxa responsible for the longterm 70% decline in CCS zooplankton biomass. We will establish the temporal coherence of population changes in the central and southern sectors of the CCS, with which to analyze the covariation with related zooplankton species in the Subarctic Pacific. These studies will form the foundation for the design of new GLOBEC field studies and the development of NE Pacific pelagic ecosystem models.