Response Of Microbial Community Structure And Protistan Grazing Pathways To Environmental Forcing In The Arabian Sea

[9311246 . Landry]阿拉伯海是世界海洋中一个充满活力的区域，受季风强烈的季节性逆转所驱动。在相对恒定的热带光照下，该地区在海洋生产系统的联合全球空间尺度“极端”（沿海上升流到开阔海洋少营养）的背景下很有趣。因此，它是一个天然的实验室，可以测试物理强迫、食物结合结构、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的消费者的作用，并有助于了解浮游生物群落结构、新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）季风间期和夏季（8月）西南季风季节进行，这两个季节的差异最明显。细菌和浮游植物的丰度、生物量和特定生长率将通过流式细胞术、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。将确定和量化以微浮游生物和纳米浮游生物为食的主要微型浮游动物，并通过一套补充方法测量其放牧的影响，包括稀释、荧光标记猎物、大小分选和特定代谢抑制剂。该项目的结果将有助于了解全球气候变化如何影响盛行的强迫风，将改变浮游植物群落结构，反过来，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。

9311246 Landry 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 understanding 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.