Collaborative Research: Elucidating algal host-virus dynamics in different nutrient regimes - mechanistic interactions and biogeochemical impact

合作研究：阐明不同营养状况下藻类宿主病毒的动态 - 机械相互作用和生物地球化学影响

• 批准号: 1537951
• 负责人: Kay Bidle
• 金额: $ 48.16万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1537951&HistoricalAwards=false
• 关键词: Collaborative; Research; Elucidating; algal; host

Marine phytoplankton, photosynthetic microscopic organisms that float with the oceans currents, account for ~50% of the Earths primary productivity. When there are sufficient nutrients and light to sustain their growth, phytoplankton thrive and produce large-scale blooms in the world oceans that can be seen from Earth-observing satellites. Coccolithophores are arguably one of the most dominant and globally distributed phytoplankton. Their dual ability to produce calcium carbonate cell walls and to use carbon dioxide for photosynthesis make them a key component of the oceanic carbon cycle and marine ecosystems. As such, water column processes that impact the fate of this cellular carbon are of critical importance. Emiliania huxleyi is a globally widespread, cosmopolitan coccolithophore that forms blooms in all but the polar oceans. These blooms are routinely terminated by virus infection (Coccolithoviruses), which results in cell death and the release of organic matter into the upper ocean. At the same time, infection triggers the production and release of a sticky mucus-like gel which serves to aggregate free floating cells (and even viruses) into larger particles that have very high sinking rates into the deep ocean. Hence, viruses play multifaceted roles in determining whether phytoplankton carbon sinks to the deep ocean and is sequestered away from the atmosphere or is recycled in the upper ocean free to exchange with the atmosphere. Ultimately, factors that impact the interactions between phytoplankton cells and viruses are likely to affect the direction of carbon flow in the oceans. This project uses a well-characterized, laboratory-based coccolithophore-virus system (E. huxleyi and Coccolithoviruses) to elucidate the basic mechanisms that underlie host-virus interactions at the levels of adsorption, replication and production. The researchers will manipulate nutrient supply to understand its impact on mechanisms of infection and to better interpret population changes in different oceanic regimes. A key tenet is to investigate the role of mucus-like gels and calcium carbonate cell walls, both of which are produced under nutrient stress, as important first order drivers in host-virus interactions. Experimental work will be integrated into mathematical models as a tool to extrapolate our findings and postulate how, to first order, viruses control the fate of phytoplankton populations in the ocean. Research concepts and findings will be relayed to broader audiences by developing an online educational software tool and web app (via the Rutgers University Mobile App Development group) that focuses on the use of mathematical modeling in marine science. It will be designed to meet national requirements for the Next Generation Science Standards (NGSS) for 15-16 year olds. Students will learn about patterns of ocean productivity, articulate how and why ocean ecosystems are sensitive to environmental change, and understand the role of viruses in ecosystem structure. To ensure large-scale distribution of the app, with a particular aim to reach underrepresented students and to address the NGSS, Rutgers will host workshops to familiarize the teachers with the science, the scientists, and effective use of the app and associated lessons. The investigators will work with external evaluators to assess the effectiveness of these activities and deliverables. Research activities will also be communicated to the general public by interactions with the 'Liquid Living' display at the San Francisco Exploratorium and the annual 'Nautical Night' at the MIT museum in Boston, MA.Phytoplankton are the basis of marine food webs and are responsible for approximately half of global net primary production. As highly abundant infectious entities in the oceans, marine viruses can cause the demise of phytoplankton blooms and drive the release of dissolved and particulate organic matter (DOM and POM), which stimulates microbial activity, facilitates bacterial re-mineralization, enhances nutrient recycling and respiration, as well as short-circuits carbon transport to higher trophic levels. At the same time, enhanced production and release of "sticky" colloidal cellular components, such as transparent exopolymer particles (TEP), during viral lysis can cause particle aggregation and enhance carbon export. As yet, the dynamics of phytoplankton infection by viruses and the balance between these diametrically opposed ecosystem pathways has not been fully characterized under different physicochemical conditions. An enhanced mechanistic and quantitative understanding of host-virus interactions can critically inform and constrain ecosystem models and allow researchers to ascertain and quantify its ecological and biogeochemical impacts on large spatial scales. This collaborative project aims to bridge existing gaps in our mechanistic and quantitative understanding of viruses as agents of phytoplankton mortality and their impact on biogeochemical processes. The ability of ecosystem models to predict carbon flow in marine systems is limited, in part, by a lack of appropriate information regarding the nutrient sensitivity of fundamental infection parameters: viral adsorption rates onto/into hosts, virus replication efficiency and latent period, and the production of infectious viruses and their excretion into the surrounding medium. Using lab-based experiments with a coccolithophore host-virus model system, as well as extensive datasets from virus infected natural coccolithophore blooms in the North Atlantic, this project aims to elucidate the impact of nutrient limitation and host cell fitness on virus infection and to what degree the dependence of viral infection on nutrient supply impacts large scale biogeochemistry and biogeography of a globally significant phytoplankton species. This interdisciplinary approach combines grounded molecular- and flow cytometry-based diagnostic techniques, with the development of a mathematical model of infection, to understand the primary mechanisms underlying observed host-virus dynamics. The investigators will embed the mathematical model of infection dynamics into a global ecosystem model, so we may understand the ecological impact of phytoplankton infection by viruses, and its dependence on nutrient supply, on large spatial scales.

海洋浮游植物，随着海洋水流漂浮的光合微观生物，占地球主要生产力的约50％。当有足够的营养和光来维持其生长时，浮游植物在世界海洋中蓬勃发展并产生大规模的花朵，可以从焦地观察的卫星中看到。可以说，可去核细胞流团是最优势和全球分布的浮游植物之一。它们产生碳酸钙细胞壁并使用二氧化碳进行光合作用的双重能力使它们成为海洋碳循环和海洋生态系统的关键组成部分。因此，影响该细胞碳的命运的水柱过程至关重要。艾米利亚尼亚·赫x黎（Emiliania Huxleyi）是全球广泛的国际化球菌，在极地海洋以外的所有人都形成了盛开。这些开花通常通过病毒感染（Coccolithovires）终止，这导致细胞死亡和有机物释放到上海洋。同时，感染触发了粘性粘液样凝胶的产生和释放，该凝胶可将自由浮动细胞（甚至病毒）聚集到较大的颗粒中，这些颗粒具有很高的下沉速率进入深海。因此，病毒在确定浮游植物碳是否沉入深海中，脱离大气层或在上海中回收以与大气交换的上海中发挥了多方面的作用。最终，影响浮游植物细胞和病毒之间相互作用的因素可能会影响海洋中的碳流动方向。该项目使用一个良好的，基于实验室的可核大理石病毒系统（E. huxleyi和Coccolithovires）来阐明基本的基本机制，这些机制构成了宿主病毒相互作用的基本机制，以吸附，复制和生产水平。研究人员将操纵养分供应，以了解其对感染机制的影响，并更好地解释不同海洋政权的人口变化。一个关键的宗旨是研究粘液样凝胶和碳酸钙细胞壁的作用，这两者都是在营养应激下产生的，也是宿主病毒相互作用中重要的一阶驱动因素。实验工作将集成到数学模型中，作为推断我们发现的工具，并假定一阶病毒如何控制海洋浮游植物种群的命运。研究概念和发现将通过开发在线教育软件工具和Web应用程序（通过Rutgers University Mobile App开发小组）来传达给更广泛的受众，该工具专注于在海洋科学中使用数学建模。它将旨在满足15-16岁的下一代科学标准（NGSS）的国家要求。 学生将了解海洋生产力的模式，阐明海洋生态系统如何以及为什么对环境变化敏感，并了解病毒在生态系统结构中的作用。为了确保该应用程序的大规模分发，特定的目的是吸引代表性不足的学生并向NGSS讲话，Rutgers将举办研讨会，以使教师熟悉科学，科学家，并有效地使用该应用程序和相关的课程。调查人员将与外部评估人员合作评估这些活动和可交付成果的有效性。研究活动还将通过与旧金山Exploratorium的“液体生活”展览的互动以及在马萨诸塞州波士顿的麻省理工学院博物馆的一年一度的“航海之夜”通过互动传达给公众。负责大约一半的全球净初级生产。由于海洋中高度丰富的传染性实体，海洋病毒会导致浮游植物的消亡，并驱动溶解和颗粒有机物（DOM和POM）的释放，从而刺激微生物活性，从而促进细菌性重新矿化，从而增强营养的恢复和呼吸，并增强营养的恢复性恢复和呼吸。 ，以及短路碳转运至较高的营养水平。同时，在病毒裂解过程中，增强了“粘性”胶体细胞成分（例如透明的外聚合物颗粒（TEP））的产生和释放会导致颗粒聚集并增强碳输出。到目前为止，在不同的物理化学条件下，病毒感染浮游植物感染的动力学以及这些截然相对的生态系统途径之间的平衡尚未得到充分表征。对宿主病毒相互作用的增强的机械和定量理解可以严格为生态系统模型提供信息和限制，并使研究人员能够确定和量化其生态和生物地球化学对大空间尺度的影响。这个协作项目旨在弥合我们对病毒的机械和定量理解，作为浮游植物死亡率及其对生物地球化学过程的影响。生态系统模型预测海洋系统中碳流的能力部分受到限制，部分原因是缺乏有关基本感染参数的营养敏感性的适当信息：病毒吸附率到宿主中，病毒复制效率和潜在时期，以及潜伏期传染病的产生及其排泄物到周围的培养基中。使用基于实验室的实验与甲状腺菌的宿主病毒模型系统，以及北大西洋病毒感染天然可质体花朵的广泛数据集程度，病毒感染对养分供应的依赖性影响了全球浮游植物物种的大规模生物地球化学和生物地理学。这种跨学科的方法结合了基于基于流式细胞术的基于基于流式细胞术的诊断技术，并开发了感染的数学模型，以了解观察到的宿主病毒动力学基础的主要机制。研究人员将感染动力学的数学模型嵌入全球生态系统模型中，因此我们可以了解病毒感染浮游植物的生态影响及其对养分供应的依赖在大空间尺度上。