The molecular ecology of phytoplankton and their viruses

浮游植物作为水环境中的主要初级生产者，在水生食物链中起着基础性的作用，并影响着全球的化学循环。除了滋养绝大多数水生生物外，浮游植物还通过将二氧化碳转化为有机碳来消除大气中的二氧化碳；海洋浮游植物产生的有机物质的很大一部分从表层水域沉入深海，在那里它与大气隔离了数百年或数千年。病毒在水环境中大量存在，许多浮游植物物种对病毒感染很敏感，这一发现表明，病毒是浮游植物死亡的重要来源，可能会影响水生食物网和全球化学循环。尽管人们对水生病毒的科学兴趣与日俱增，但直接证明病毒对浮游植物种群和群落的影响的经验数据极其有限。因此，我研究的长期目标是确定浮游植物-病毒生态的各个方面是否可预测，以及病毒的影响是否需要包括在初级生产和浮游植物生态的模型中。这些长期目标将通过努力实现四个具体目标来实现，这些目标侧重于浮游植物-病毒生态学中描述不多但关键的主题。具体目标是：1)确定不同淡水环境中浮游植物病毒的生物多样性和季节动态；2)量化病毒对浮游植物死亡率的相对重要性；3)确定病毒是否影响浮游植物的竞争；以及4)确定环境条件是否影响浮游植物对病毒感染的敏感性和抵抗力。最终，这项工作将开发和促进水生微生物学的先进研究技术，并将通过建立更准确、更现实的浮游植物生态和水生初级生产模型，加深我们对浮游植物在全球化学循环中的作用的理解。

As the major primary producers in aquatic environments, phytoplankton play a fundamental role in aquatic food webs and influence global chemical cycles. Besides nourishing the vast majority of aquatic life, phytoplankton remove carbon dioxide from the atmosphere by converting it into organic carbon; a significant portion of the organic material produced by marine phytoplankton sinks out of the surface waters into the deep ocean where it remains isolated from the atmosphere for hundreds, or thousands of years. The discovery that viruses are abundant in aquatic environments, and that many phytoplankton species are susceptible to virus infection suggests that viruses are an important source of phytoplankton mortality that may influence aquatic food webs and global chemical cycles. Despite the growing scientific interest in aquatic viruses, empirical data directly demonstrating the effects of viruses on phytoplankton populations and communities is extremely limited. Therefore, the long-term objectives of my research are to determine if aspects of phytoplankton-virus ecology are predictable, and if the effects of viruses need to be included in models of primary production and phytoplankton ecology. These long-term objectives will be accomplished by working towards four specific objectives that focus on poorly described, but critical topics in phytoplankton-virus ecology. The specific objectives are: 1) to determine the biodiversity and seasonal dynamics of phytoplankton viruses in different freshwater environments, 2) to quantify the relative importance of viruses to phytoplankton mortality, 3) to determine if viruses influence phytoplankton competition, and 4) to determine if environmental conditions influence phytoplankton susceptibility and resistance to virus infection. Ultimately, this work will develop and promote advanced research technologies for aquatic microbiology, and will increase our understanding the role of phytoplankton in global chemical cycles by enabling more accurate, realistic models of phytoplankton ecology and aquatic primary production.