Collaborative Research: Seasonal bloom dynamics: Synechococcus-grazer interactions as a model system

聚藻属的蓝藻是微小的，但在温带海洋中无处不在的浮游植物，它们在海洋食物网的基础上贡献了大量的生物量。聚囊球菌的季节性繁殖是大西洋和太平洋沿岸水域的一个显著一致的特征。然而，新的分子技术揭示了这些花的一致性背后是丰富的遗传变异，表现出快速的动态周转。这导致了一种假设，即聚球菌内的遗传多样性对维持季节性繁殖和预测海洋生态系统对长期环境变化的反应具有重要的生态学意义。这个项目将结合生态学和基因组学的方法来了解遗传多样性是如何与物理和食物网过程相互作用的，这些过程驱动了聚囊球菌繁殖的季节性循环。在缅因湾布斯湾和南加州斯克里普斯码头的繁殖期，每周将对聚球菌和共生微生物的遗传多样性进行量化。流式细胞分选与分子方法相结合，将利用三层方法研究华花组合的多样性，包括：整个未分选群落的DNA和RNA分析，流式分选群落的DNA分析，聚藻球菌及其原生食草动物的单细胞基因组学。生态过程导致藻华结束将通过实验进行调查，旨在衡量原生食草动物与各种藻属生态型病毒的死亡率的相对重要性。这些结果将有助于深入了解水华动态以及遗传多样性如何与生态系统过程相互作用。这一项目将开发各种方法和资源，这些方法和资源将普遍有助于量化浮游植物季节性繁殖的可变性，这可能是生态系统对长期气候变化反应的早期指标。将设计定量PCR方法，快速定量测定海水中聚囊球菌和食聚囊球菌的多样性。许多原生生物和聚球菌的单扩增基因组将被生产和冷冻保存，以便于未来的研究。该项目还将支持一名研究生和几名本科生的研究训练，他们将密切参与个别项目。研究结果将转化为毕格罗实验室举办的正式课程，并通过每年夏天在布斯湾港举办的成功的每周caf<s:1> Scientifique系列活动向公众介绍。

Cyanobacteria in the genus Synechococcus are minute, but ubiquitous phytoplankton of temperate oceans that contribute a large amount of the biomass produced at the base of marine food webs. Seasonal blooms of Synechococcus are a remarkably consistent feature of coastal water of both the Atlantic and Pacific oceans. However, new molecular techniques have revealed that underlying the consistency of these blooms is a wealth of genetic variation that exhibits rapid dynamical turnover. This has led to a hypothesis that genetic diversity within Synechococcus is ecologically important to sustaining seasonal blooms, and to predicting marine ecosystem response to longer term environmental change. This project will combine ecological and genomic approaches to understand how genetic diversity interacts with the physical and food web processes that drive seasonal cycles of Synechococcus blooms. The genetic diversity of Synechococcus and co-occurring microbes will be quantified on a weekly basis during bloom periods in Booth Bay, Gulf of Maine and Scripps Pier, Southern California. Flow cytometric cell sorting in combination with molecular approaches will be utilized to investigate the diversity of bloom assemblages using a three-tiered approach including: DNA and RNA analysis of the whole unsorted community, DNA analysis of flow-sorted communities, and single cell genomics of Synechococcus and their protist grazers. Ecological processes that cause Synechococcus blooms to end will be investigated through experiments designed to measure the relative importance of mortality from protist grazers versus from viruses on various Synechococcus ecotypes. These results will yield insights into bloom dynamics and how genetic diversity interacts with ecosystem processes.This project will develop methods and resources that will be generally useful for quantifying variability of the seasonal bloom of phytoplankton, which is likely to be an early indicator of ecosystem responses to longer term climate change. Quantitative PCR methods will be designed for rapid quantification of diversity in Synechococcus and in Synechococcus grazers in marine waters. Numerous protist and Synechococcus single amplified genomes will be produced and cryo-preserved to enable future studies. This project will also support the research training of a graduate student and several undergraduate students, who will be intimately involved with individual projects. Results will be translated to formal courses held at Bigelow Laboratory and to the public through presentations at a successful weekly Café Scientifique series held in Boothbay Harbor each summer.