Microzooplankton Grazing Interactions in the Central Equatorial Pacific

赤道中太平洋是一个广阔的高纬度地区， 营养上升流，初级生产力增强， 联合国特别感兴趣的浮游生物浓度 全球海洋通量研究（JGOFS），因为它可能占20 估计全球向深海排放的碳量的50%， 海本研究的总体目标是为 了解初级生产、食物、 网络结构，以及这一过程中的地球化学循环和通量 作为JGOFS赤道太平洋方案的一个组成部分。 这项研究利用了一套互补的实验 方法（荧光标记的猎物颗粒，代谢 抑制剂和海水稀释）和流式细胞术技术 确定主要的微型消费者群体，并衡量他们的 放牧率，行为和社区的影响，在不同的 时空尺度。具体而言，研究将1） 确定的分布，丰度，和生物量的微微和 微型浮游生物群落及其随深度和 跨赤道断面纬度，2）确定和量化 占优势的微型浮游动物吃皮科和微型浮游生物 群落，3）确定微型浮游动物的放牧影响 对细菌、原绿藻、 蓝藻和藻类作为深度，一天中的时间， 营养状态，4）评估假设，有一个 一般大小关系联系放牧的影响率 微型浮游生物种群，并测试假设的作用 混合营养型鞭毛藻之间将增加沿着 环境梯度从富营养（营养丰富）到 贫营养（营养不良）系统和低光照水平下， 透光层

The central equatorial Pacific is an extensive region of high nutrient upwelling, enhanced primary productivity, and elevated plankton concentrations that is of special interest to the Joint Global Ocean Flux Studies (JGOFS) because it may account for 20 to 50% of the estimated global rate of carbon export to the deep sea. The general goal of this research is to contribute to understanding the relationships among primary production, food- web structure, and biogeochemical cycling and fluxes in this region as a component of the JGOFS Equatorial Pacific Program. The research utilizes a complementary set of experimental approaches (fluorescently-labelled prey particles, metabolic inhibitors, and seawater dilution) and flow cytometry techniques to identify major microconsumer groups and to measure their grazing rates, behaviors, and community impacts at different temporal and spatial scales. Specifically, the research will 1) determine the distributions, abundances, and biomass of pico- and nanoplankton communities and their variations with depth and latitude on cross-equatorial transects, 2) identify and quantify the dominant microzooplankton grazers on pico- and nanoplankton communities, 3) determine the grazing impact of microzooplankton on component populations of bacteria, prochlorophytes, cyanobacteria, and algae as functions of depth, time of day, and trophic state, 4) evaluate the hypothesis that there is a general size relationship linking the rates of grazing impact on picoplankton populations, and test the hypotheses that the role of mixotrophy among planktonic flagellates will increase along environmental gradients from eutrophic (nutrient-rich) to oligotrophic (nutrient-poor) systems and at low light levels in the euphotic zone.