Response of Microbial Community Structure and Protistan Grazing Pathways to Environmental Forcing in the Arabian Sea

9612509坎贝尔阿拉伯海是世界海洋中一个充满活力的区域，季风的强烈季节性逆转推动了这一区域的发展。在全球联合空间尺度的背景下，该区域令人感兴趣的是，在相对恒定的热带光照下，海洋生产系统的“极端”--沿海上升流到开阔海洋的稀有营养。因此，这是一个天然的实验室，用来测试物理强迫、食物结构、生物地球化学循环和通量以及沉积物中的碳埋藏之间的概念联系。该项目的总体目标是评估微型浮游动物作为细菌和浮游植物生产消费者的作用，并有助于了解浮游生物群落结构、新的生产和生物地球化学通量之间的关系及其对阿拉伯海物理强迫的反应。该项目将在春季(4月)季风季和夏季(8月)西南季风季进行，这两个季节的差异应该最明显。细菌和浮游植物的丰度、生物量和比生长率将通过流式细胞仪、显微镜和色素分析来确定，以确定它们随季节、深度和位置的变化。将确定和量化微型浮游动物对微微型浮游生物和微型浮游生物的主要捕食者，并将通过一套补充方法来衡量它们的放牧影响，包括稀释法、荧光标记的猎物、粒度分级和特定的代谢抑制剂。该项目的结果将有助于理解全球气候变化如何影响盛行的强风，如何改变浮游植物群落结构，以及这些食物网结构的变化如何影响上层水柱的碳储存和输出。***

9612509 Campbell The Arabian Sea is an intensely dynamic region of the world's oceans driven by strong seasonal reversals in monsoon winds. The region is interesting in the context of the Joint Global spatial scales "extremes" in ocean production systems -coastal upwelling to open ocean oligotrophic -- under relatively constant tropical illumination. It is thus a natural laboratory to test conceptual linkages among physical forcing, food-wed structure, biogeochemical cycling and fluxes, and carbon burial in the sediments. The general goals of this project are to asses the roles of microzooplankton as consumers of bacterial and phytoplankton production and to contribute to nderstanding the relationships among plankton community structure, new production, and biogeochemical fluxes and their responses to physical forcing the Arabian Sea. The project is to be conducted during the spring (April) intermonsoon and summer (August) SW monsoon seasons, when the most dramatic differences should be evident. Abundance, biomass, and specific growth rates of bacteria and phytoplankton will be determined by flow cytometric, microscopic, and pigment analyses to determine their variations with season, depth and location. The dominant microzooplankton grazers on pico- and nanoplankton will be identified and quantified, and the impact of their grazing will be measured with a suite of complementary methods including dilution, fluorescently-labelled prey, size- fractionation, and specific metabolic inhibitors. Results of this project will contribute to understanding how global climate changes, which may affect prevailing forcing winds, will alter phytoplankton community structure and in turn how these changes in structure of the food web affect carbon storage and export from the upper water column. ***