Collaborative Research: Quantifying competing loss rates of viral lysis and microzooplankton grazing on Emiliania huxleyi mortality

合作研究：量化病毒裂解和微型浮游动物放牧对艾米利亚赫胥黎死亡率的竞争损失率

• 批准号: 1459190
• 负责人: Matthew Johnson
• 金额: $ 60.3万
• 依托单位: Woods Hole Oceanographic Institution
• 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: 2015-05-01 至 2018-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1459190&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantifying; competing; loss

Processes that either promote growth or cause mortality drive the abundance of all organisms. For microbes such as phytoplankton, that have a lifespan measured in hours to days, small changes in these processes can have significant impacts. Phytoplankton are the central currency in the flow of material and nutrients throughout the marine environment. Even small shifts in their growth and mortality rates will have large-scale implications for ecosystem structure and biogeochemical cycling. While factors that influence growth are often examined, less is known regarding the regulation of phytoplankton mortality. This project will focus on quantifying competing modes of mortality on the bloom-forming coccolithophore, Emiliania huxleyi, a globally important phytoplankton species that contributes significantly to ocean carbon and sulfur cycles. Mortality due to grazing by single-celled microzooplankton is the largest contributor to phytoplankton loss in the marine environment. However, E. huxleyi also has a well-characterized relationship with a virus that can result in mass mortality. Therefore, E. huxleyi serves as a good model organism for examining how mortality is partitioned between grazing by microzooplankton predators and lysis due to viral infection. Quantifying these mortality mechanisms will help to inform mathematical models for the accurate prediction of shifts in E. huxleyi population dynamics and ultimately, primary production and biogeochemical cycling. This work will involve collaboration with a high school science teacher in a school system with a large proportion of students from underrepresented groups, in the creation and implementation of short film clips that depict important ecological interactions. These film clips will then be incorporated into laboratory activities to communicate these concepts to students. Further, undergraduate students from underrepresented groups will be trained at both Woods Hole Oceanographic Institute and Rutgers University, to perform laboratory research on mortality processes on phytoplankton. This research will also provide training and career development for a postdoctoral scientist.Mortality mechanisms in phytoplankton have generally been studied independent from one another, however in nature, these processes act concurrently. The relative proportion that microzooplankton grazing and viral lysis contribute to overall E. huxleyi loss and how they may interact to shape bloom dynamics is largely unknown. Understanding the relative importance of these processes, as well as their interaction, is critical due to their contrasting influence on the structure and function of marine food webs and biogeochemical cycles. While grazing tends to channel phytoplankton biomass to higher trophic levels, viral lysis stimulates microbial loop activity and vertical particle export flux. This research will determine the effect of one mortality process on the other, as well as their net effect on E. huxleyi population dynamics and export in both laboratory and field mesocosm experiments. This integrated approach will provide a unique mechanistic perspective of multi-trophic microbial interactions, thereby increasing the potential for accurate predictions of E. huxleyi population dynamics and biogeochemical cycling. The outcomes of this research have the potential to yield broadly applicable insights into how microbial interactions can drive ecological and biogeochemical dynamics in the marine environment.

促进生长或导致死亡率的过程推动了所有生物的丰富性。对于在数小时至几天内测得的寿命的微生物，例如浮游植物，这些过程的微小变化可能会产生重大影响。浮游植物是整个海洋环境中材料和养分流的中心货币。即使在其生长率和死亡率的微小变化也将对生态系统结构和生物地球化学循环产生很大的影响。尽管经常检查影响生长的因素，但对于浮游植物死亡率的调节而言，知之甚少。该项目将着重于量化形成花花公子的竞争模式，艾米利亚尼亚·赫xleyi（Emiliania Huxleyi），这是一种全球重要的浮游植物物种，对海洋碳和硫循环产生了重大贡献。单细胞微Zooplankton因放牧而导致的死亡率是海洋环境中浮游植物损失的最大贡献者。但是，Huxleyi E. Huxleyi也与病毒具有良好的关系，可能导致质量死亡。因此，E。huxleyi是一种很好的模型生物体，用于研究如何在微Zooplankton捕食者放牧与病毒感染引起的裂解之间分配死亡率。量化这些死亡率机制将有助于为数学模型提供信息，以准确预测Huxleyi人口动态的转移以及最终的一级生产和生物地球化学循环。这项工作将涉及与一位高中科学老师在学校系统中的合作，其中大部分代表性群体的学生很大一部分的学生在创建和实施短片剪辑中描绘了重要的生态互动。然后，这些电影片段将被纳入实验室活动中，以将这些概念传达给学生。此外，来自代表性不足小组的本科生将在伍兹霍尔海洋学院和罗格斯大学接受培训，以在浮游植物的死亡过程中进行实验室研究。这项研究还将为博士后科学家提供培训和职业发展。浮游植物中的病态机制通常彼此独立研究，但是在自然界中，这些过程同时起作用。 Microzooplankton放牧和病毒裂解的相对比例有助于整体杂志的Huxleyi损失以及它们如何相互作用以形成Bloom动力学。由于它们对海洋食品网和生物地球化学周期的结构和功能的影响，了解这些过程的相对重要性以及它们的相互作用至关重要。放牧倾向于将浮游植物生物量传达到更高的营养水平，但病毒裂解会刺激微生物环的活性和垂直颗粒导出通量。这项研究将确定一种死亡过程对另一个死亡率的影响，以及它们对实验室和现场中验实验中的Huxleyi人群动态和出口的净影响。这种综合方法将为多营养微生物相互作用提供独特的机械透视，从而增加了对Huxleyi E. huxleyi人群动力学和生物地球化学循环的准确预测的潜力。这项研究的结果有可能对微生物相互作用如何推动海洋环境中的生态和生物地球化学动态产生广泛适用的见解。