GLOBEC 2000: Long-term Changes in California Current Zooplankton Assemblages and Euphausiid Population Dynamic Parameters

PIS将通过对东北太平洋不同区域浮游动物种群的比较分析以及大气和海洋强迫的测量，检验GLOBEC的核心假设，即阿拉斯加湾沿岸和加州海流系统的生产制度是不同的，并通过大气和海洋强迫耦合。在第一阶段研究中，PIS揭示了加州当前浮游动物(区域I)在年代际时间尺度上的重大变化(例如，盐碱地和真甲虫制度的变化)以及年际时间尺度上的变化(例如，与厄尔尼诺有关的桡足类多样性和浮游动物生物量的变化)。在第二阶段，PIS将集中在加利福尼亚州中部/北部附近的CCS区域II，以确定他们检测到的明显扰动在CCS的不同区域是否在空间上是一致的，并与东北太平洋其他地方，特别是俄勒冈州附近和阿拉斯加州海岸的浮游动物波动有关。此外，将使用基于脂褐素的优生生物年龄测量和反向建模技术来估计东北太平洋优生生物种群的瞬时、特定阶段的死亡率。还将使用浮游动物稳定同位素来研究食物网结构的长期稳定性。

The PIs will test the GLOBEC core hypothesis that production regimes in the Coastal Gulf of Alaska and Califomia Current System covary, and are coupled through atmospheric and oceanic forcing, through comparative analysis of zooplankton populations and measures of atmospheric and oceanic forcing in different regions of the NE Pacific. During a Phase 1 study, the PIs uncovered substantial changes in the California Current zooplankton (Region I) on interdecadal time scales (e.g., changes in salp and euphausiid regimes) as well as interannual time scales (e.g., El Nino-related changes in copepod diversity and zooplankton biomass). For Phase 2 , the PIs will focus on Region II of the CCS off central/northern California to determine whether the pronounced perturbations that they detected are spatially coherent in different regions of the CCS and are linked to zooplankton fluctuations elsewhere in the NE Pacific, specifically off Oregon and in the Coastal Gulf of Alaska. In addition, estimates of instantaneous, stage-specific mortality rates for euphausiid populations of the NE Pacific will be made using lipofuscin-based measures of euphausiid age and inverse modeling techniques. Long-term stability in food web structure also will be investigated using zooplankton stable isotopes.