SGER: Southern and Coastal Extent of Picophytoplankton Populations in the South Pacific

海洋浮游植物中最丰富和最普遍的成员属于两个蓝藻属，聚藻球菌和原绿球藻，它们共同贡献了开放海洋中一半以上的初级生产力。这些属中的每一个都在海洋蓝藻中形成了一个独特的浮游植物分支，可以进一步细分为多个系统发育分支（称为基因型或生态型），其中一些具有明确的生理特征，可以与其生态分布有关。然而，各种基因型的水平分布边界尚未完全清楚，南大西洋研究之间的差异需要进一步研究浮游植物的分布，特别是原绿球藻种群的分布。2008年12月，在福克兰群岛附近南纬40度，西经57度至南纬53度，西经55度之间的巴塔哥尼亚陆架区域进行了一次研究巡航，PI将能够检查浮游植物种群的南部范围，以及通过陆架断裂锋面向东进入少营养水域的分布。在代表不同水类型的站点，将收集样品用于浮游植物种群的流式细胞分析，将过滤用于随后的原绿球藻和聚囊球菌生态型的qPCR分析，并将冷冻保存以使用高通量培养方法进行分离。这个SGER项目将提供一个新的浮游植物种群南部和沿海范围的数据集，并可能解决原绿球藻种群是否比十多年前最初观察到的更向南扩展到更冷的水域的问题。此外，它将使MS学生参加研究巡航并获得实地研究经验，为用品和运输样品提供资金，并提供MS学生分析样品的津贴。

The most abundant and ubiquitous members of the marine phytoplankton belong to two cyanobacterial genera, Synechococcus and Prochlorococcus, which together contribute more than half of the primary productivity in the open ocean. Each of these genera, which form a distinct picophytoplankton clade within the marine cyanobacteria, can be further subdivided into multiple phylogenetic clades (referred to as genotypes or ecotypes), some of which have clear physiological characteristics that can be related to their ecological distributions. However, the boundaries of the horizontal distributions of the various genotypes are not fully understood, and discrepancies between studies in the South Atlantic require further examination of the picophytoplankton distributions, particularly of the Prochlorococcus populations. In a research cruise during Dec 2008 to the Patagonia shelf region from ~40 deg S, 57deg W to ~53 deg S, 55 deg W near the Falkland Islands, the PI will be able to examine the southern extent of picophytoplankton populations as well as the distributions across the shelf break front going east into oligotrophic waters. At stations representing different water types, samples will be collected for flow cytometric analysis of picophytoplankton populations, will be filtered for later qPCR analysis of Prochlorococcus and Synechococcus ecotypes, and will be cryopreserved for isolations using high throughput culture methods.This SGER project will provide a new dataset of the southern and coastal extent of picophytoplankton populations, and possibly address the question of whetherProchlorococcus populations are extending further south into colder waters than initially observed more than a decade ago. Additionally, it will enable a MS student to participate in the research cruise and get experience with field research, provide funds for supplies and shipping samples, and provide a MS student stipend to analyze the samples.