Physiological Ecology of Marine Cyanobacterial Communities

9633111 PALENIK该项目将使用综合多调查员的方法来确定海洋环境中蓝藻生物多样性的程度和原因。该项目的假设是，海洋中的分层虽然往往是短暂的，但已导致发展出数量有限的生理和遗传上不同和可识别的群体（“种”）特别适应于高光、低营养混合层的蓝细菌和其他适应于较高营养的蓝细菌，即使是这个简单的场景也比目前的海洋学范式复杂得多。目前对自然蓝藻多样性的空间或时间变化知之甚少，我们只能猜测可能驱动它的因素。这种多样性在确定海洋速率过程中的重要性，例如原位生长或碳固定速率，是未知的，在我们了解蓝藻多样性的程度和模式之前，它的作用无法真正得到解决。该项目是能够分析个体生理或遗传类型的生长速率和代谢活动的第一步。由于类似的遗传和生理过程可能也发生在其他群体的浮游植物，这些问题是生物海洋学的普遍意义。 这个项目也将开始不仅仅关注环境中微生物“物种”的数量，而是为什么会有这么多？海洋环境中的微生物群逐渐被视为具有显著的多样性，要了解这种多样性背后的过程，最好的办法是详细研究一组相关微生物的多样性与理化参数的关系。海洋环境可能是开始理解这些问题的最佳场所，因为在理解有机体周围的物理化学梯度方面也有相当多的经验。RNA聚合酶基因序列的菌株和散装社区样品，流式细胞仪分析，色素分析，抗体测定能动聚球藻和其他菌株，菌株分离技术，生理研究氮和光的利用，和理化数据将是最初的一套工具，我们将带来这些问题，与其他正在开发中。在南加州湾贫营养边界的三个站点将在同一季节连续两年在几个深度进行采样，以确保我们的结论的可重复性。第三次航行将侧重于在不同季节确定同一地点的特征，以便开始探索多样性的时间变化。这种集中的采样工作将确保一个易于处理的方法来理解蓝藻多样性对海洋生态系统的重要性。 ***

9633111 PALENIK This project will use an integrated multi-investigator approach to determine the extent and causes of cyanobacterial biodiversity in the marine environment. The project hypothesis is that stratification in the oceans, although often transient, has led to the development of a limited number of physiologically and genetically distinct and recognizable groups ("species") of cyanobacteria specifically adapted to the high light, low nutrient mixed layer and others adapted to the higher nutrient, low light life below it. Even this simple scenario is much more complex than the current oceanographic paradigm. There is currently little knowledge of the spatial or temporal variations in natural cyanobacterial diversity, and we can only guess at the factors that may be driving it. The importance this diversity may have in determining oceanographic rate processes, such as in situ growth or carbon fixation rates, is unknown, and its role cannot really be addressed until we understand the extent and patterns of cyanobacterial diversity. This project is the first step in being able to assay the growth rates and metabolic activities of individual physiological or genetic types. Since similar genetic and physiological processes probably also occur in other groups of phytoplankton, these questions are of general significance to biological oceanography. This project will also begin to look at not just the number of microbial "species" in an environment, but why that number? The microbiota of the marine environment are coming to be seen as remarkably diverse, and an understanding of the processes underlying this diversity will best be gained by examining the diversification of a related group of microorganisms in detail in relationship to physiochemical parameters. The marine environment is probably the best place to begin to understand these questions because there is also considerable experience in understanding the physiochemical gradients surrounding the o rganisms. RNA polymerase gene sequences from strains and bulk community samples, flow cytometric analyses, pigment analyses, antibody assays for motile Synechococcus and other strains, strain isolation techniques, physiological studies on nitrogen and light utilization, and physiochemical data will be the initial set of tools we will bring to these problems, with others under development. Three sites in the oligotrophic boundary of the Southern California Bight will be sampled at several depths for two consecutive years at the same season to ensure the reproducibility of our conclusions. A third cruise will focus on characterizing the same sites at a different season in order to begin to explore temporal variations in diversity. This focused sampling effort will ensure a tractable approach to understanding the importance of cyanobacterial diversity to marine ecosystems. ***