U.S.GLOBEC: Cross-Functional Processes and Zooplankton Recruitment Variability on Georges Bank - Diet of Calanus Finmarchicus Copepods and Nauplii

US-GLOBEC: Georges Bank - Calanus finmarchicus Copepodids and Nauplii的食物上的前额交叉过程和补充变异。该项目将研究控制海洋动物在时间和空间上的分布和丰度的生物和物理过程，特别是与前额交叉过程有关的过程。本建议的具体重点是定量描述纳米和微型浮游生物猎物场对银行目标桡足类种群招募的贡献。我们假设位于锋面区域和混合良好的锋面（河岸）一侧的桡足类和nauplii相对于分层的锋面（岸外）一侧经历了丰富的食物环境。我们将首先通过水文调查来定义锋面，包括对纳米和微型浮游生物（即大小为2- 200um的植物和动物猎物）的CTD/rosette采样，我们在GLOBEC西北大西洋项目的第一和第二阶段的研究表明，目标桡足类和幼鱼大量利用了这些猎物。将对这些生物的交换率进行评估，并将其与来自相同水文模型的保守水柱性质的交换率进行比较。我们将在两个具有不同季节特征的交叉锋区(1)2 - 3月地表热信号最强的东北峰锋区(2)春末和夏季（5月下旬- 8月）将滩顶水域与南侧水域分开的潮汐混合锋区(2)，对桡足类桡足类Calanus finmarchicus的桡足类和捕食阶段的纳米和微型浮游生物进行捕食场评价和消耗测量。我们之所以关注C finmarchicus，是因为该物种在1 - 6月期间在乔治滩浮游动物生物量中占主导地位。我们强调东北峰和南翼的锋面，因为这些是水、营养物质和浮游生物进入银行的潜在地点。我们将重点放在东北峰，因为与银行的其他地区相比，这里的浮游生物和底栖生物产量都有所提高。我们比较了Bank波峰和南翼之间的潮汐混合锋，因为1994-1996年期间进行的U.S.-GLOBEC研究表明，尽管C. finmarchicus nauplii在季节早期被平流到Bank波峰，但随后没有形成强大的群体，可能是由于该地区强烈的捕食压力。在船上实验中，利用自然猎物组合直接测量鹦鹉螺和桡足类动物的摄食率。杂食性摄食的直接影响将在原地猎物场和物理状态的背景下解释。最终，消费者饮食中植物和动物猎物的影响将在其他调查人员对消费者分布、条件、生活史参数和生产进行测量的背景下协同解决。

US-GLOBEC: Cross-Frontal Processes and Recruitment Variability on Georges Bank - Diet of Calanus finmarchicus Copepodids and Nauplii This program will examine the biological and physical processes controlling the distribution and abundance of marine animals in time and space, especially as related to cross-frontal processes. The specific focus of this proposal is to describe quantitatively the contribution of nano- and micro- plankton prey fields to recruitment of target copepod populations on the Bank. We hypothesize that copepods and nauplii located in frontal regions and on the well-mixed (on-Bank) side of fronts experience an enriched food environment relative to the stratified (off-Bank) side of fronts. We will first define the fronts by hydrographic surveys which include CTD/rosette sampling of the nano- and microplankton (i.e. plant and animal prey 2-200 um in size) prey field which our studies in Phases 1 and 2 of the GLOBEC Northwest Atlantic Program have demonstrated are heavily utilized by target copepods and larval fish. Exchange rates of these organisms will be evaluated and compared to exchange rates of conservative water column properties from the same hydrographic casts. We will evaluate prey fields and measure consumption of nano- and microplankton organisms by copepodid and feeding naupliar stages of the calanoid copepod Calanus finmarchicus in two cross-frontal areas which are characteristic of two different seasons: (1) the Northeast Peak Front, which exhibits its strongest surface thermal signal in February-March and (2) the Tidal Mixing Front which separates waters of the Bank crest from the southern flank during late spring and summer (late May-August). We focus on C finmarchicus because this species dominates the zooplankton biomass of Georges Bank during the January-June period. We emphasize fronts on the Northeast Peak and the Southem Flank because these are potential sites for cross-frontal transport of water, nutrients and plankton onto the Bank. We focus on the Northeast Peak because it is an area of enhanced production of both plankton and benthos relative to the rest of the Bank. And we compare zooplankton across the tidal mixing front between the Bank crest and the Southern Flank because U.S.-GLOBEC studies conducted during 1994-1996 indicate that, although C. finmarchicus nauplii are advected onto the Bank crest early in the season, strong cohorts do not subsequently develop, possibly as a result of intense predation pressure in this area. Ingestion rates of nauplii and copepodids will be measured directly in shipboard experiments using natural prey assemblages. The proximate influence of omnivorous feeding will be interpreted in the context of the in situ prey field and physical regime. Ultimately, the influence of plant versus animal prey in consumer diet will be addressed collaboratively in the context of measurements made by other investigators of consumer distribution, condition, life history parameters and production.