Physiological Ecology of Marine Cyanobacterial Communities

海洋蓝藻群落的生理生态学

• 批准号: 9633111
• 负责人: Brian Palenik
• 金额: $ 37万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9633111&HistoricalAwards=false
• 关键词: Physiological; Ecology; Marine; Cyanobacterial; Communities

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. ***

该项目将采用综合的多研究者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，海洋中的分层虽然通常是短暂的，但已经导致了有限数量的生理和遗传上独特和可识别的蓝藻群（“物种”）的发展，这些蓝藻群专门适应高光、低营养的混合层，而其他蓝藻则适应高光、低营养的混合层。即使是这种简单的情景也比目前的海洋学范式复杂得多。目前对天然蓝藻多样性的时空变化知之甚少，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，如原地生长或碳固定速率，是未知的，在我们了解蓝藻多样性的程度和模式之前，它的作用无法真正解决。该项目是能够测定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也可能发生在其他浮游植物群中，这些问题对生物海洋学具有普遍意义。这个项目不仅会关注环境中微生物“物种”的数量，还会关注为什么会有这么多？人们逐渐认识到海洋环境中的微生物群具有显著的多样性，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，因为在理解生物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大量群落样本，流式细胞分析，色素分析，抗体分析，运动聚球菌和其他菌株，菌株分离技术，氮和光利用的生理研究，以及物理化学数据将是我们将带来这些问题的初始工具，其他正在开发中。为了确保我们的结论的可重复性，我们将连续两年在同一季节在南加州海域的几个深度取样三个地点的少营养边界。第三次巡航将侧重于在不同季节描绘同一地点的特征，以便开始探索多样性的时间变化。这种集中采样的努力将确保一个易于处理的方法来了解蓝藻多样性的重要性，海洋生态系统。＊＊＊