Biogeochemical and Ecological Impacts of Amphipod Circoviruses in Benthic Habitats

端足类圆环病毒对底栖栖息地的生物地球化学和生态影响

• 批准号: 1356964
• 负责人: Ian Hewson
• 金额: $ 61.91万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1356964&HistoricalAwards=false
• 关键词: Biogeochemical; Ecological; Impacts; Amphipod; Circoviruses

Overview: This project will investigate how circoviruses influence the herbivory/detritivory rates of benthic amphipods through the study of an experimental gradient of viral prevalence and by addition of cultivated viruses. The hypotheses to be tested are: H1: Circoviruses cause decreased detritivory and herbivory by infected amphipod hosts; H2: Circoviral impacts on amphipods result in decreased growth rate of sediment bacteria, decreased extracellular cellulose activity of sediment microorganisms, and decreased fluxes of oxidized inorganic nutrients from sediments into overlying waters; H3: Circoviruses negatively impact the nutritional quality of their hosts. These hypotheses will be tested by conducting sediment-water mesocosm experiments to assess the impacts of circoviruses on aquatic vegetation breakdown, and subsequent impacts on biogeochemistry, including bacterial production, efflux of reduced N into overlying waters, and production of dissolved organic C. Finally, this project will examine how circoviruses influence the nutritional quality of amphipods by examining elemental ratios of amphipod populations from high to low circoviral prevalence and experimentally infected amphipods. Data from these three approaches will be used to form a model of how circoviruses influence benthic foodwebs and biogeochemical cycles in sediment habitats. This study focuses on circoviruses within two ecologically sensitive amphipods that are crucial to ecosystem function: Diporeia (in Lake Michigan), which has experienced dramatic decline in abundance over the last 20 years within the Great Lakes, and Peramphithoe femorata, which is a major consumer of the environmentally threatened giant kelp Macrocystis pyrifera on the US West Coast.Intellectual Merit: Decades of research have identified the importance of viruses in aquatic ecology and biogeochemistry.However, most studies have focused on bacteriophage and viruses of eukaryotic microorganisms. Metazoa are important drivers of benthic biogeochemistry, where they cause bioirrigation of anoxic sediments, resuspension, settlement of particulate matter, facilitating nutrient fluxes from sediments to overlying waters, and potentially influencing ocean-scale processes like sediment denitrification. Circoviruses have been identified as a common constituent of crustacean viral assemblages, where they are well correlated with host death rates and population decline, and cultivated circoviruses cause death of arthropod cells. There is therefore a strong need to investigate how viruses impact the ecology of their crustacean hosts, and how in turn those impacts influence ecosystem function. Amphipods are important epifaunal constituents of benthic habitats, where they consume settled particulate matter and aquatic vegetation, which in turn influences its conversion to dissolved organic matter through microbial degradation. In turn their feeding activities stimulate benthic mineralization rates, and they are consumed by higher trophic levels. Therefore, amphipods link microbial to macrobial food webs in coastal and lake habitats. This project investigates how circoviruses infecting amphipods influence the flux of C through benthic ecosystems as a model of how viruses of metazoa influence biogeochemistry of aquatic ecosystems. The research will provide insight into how viruses influence aquatic biogeochemistry, opening up a new area of research into metazoan viruses in benthic ecosystems.Broader Impacts: The project has been designed to incorporate three broader impact activities. First, it will involve science teachers at the Newfield High School (Newfield, NY) and Oneida Lake Region high schools to directly involve and integrate high needs students into the research team to conduct experiments and laboratory analyses, culminating in presentation of their research activities to their peer group. Second, it will engage undergraduate students through summer internships at the Cornell Biological Field Station, and undergraduate researchers during the school year at Cornell to participate in the experiments and hone skills in scientific presentation. Third, it will develop extensive web-based outreach tools, including a website (incorporating live views of experiments), and social media pages targeting the general public and K-12 students. Finally, the proposed work will provide insight into the ecology of vulnerable aquatic ecosystems.

概述：本项目将通过研究病毒流行率的实验梯度和添加培养病毒，调查圆环病毒如何影响底栖端足类的食草/反食草率。待检验的假设是：H1：圆环病毒引起减少的摄食和草食性的感染端足类宿主; H2：圆环病毒对端足类的影响导致沉积物细菌的生长速度下降，沉积物微生物的细胞外纤维素活性下降，并减少氧化无机营养物质从沉积物进入上覆沃茨的通量; H3：圆环病毒对其宿主的营养质量产生负面影响。这些假设将通过进行沉积物-水围隔生态系统实验进行测试，以评估圆环病毒对水生植被破坏的影响，以及随后对生物地球化学的影响，包括细菌的产生、还原氮向上覆沃茨的流出以及溶解有机碳的产生。最后，本项目将通过检查从高到低的圆环病毒流行率和实验感染的端足类动物种群的元素比率来研究圆环病毒如何影响端足类动物的营养质量。这三种方法的数据将被用来形成一个模型，圆环病毒如何影响底栖食物网和沉积物生境的生物地球化学循环。这项研究的重点是两种生态敏感的片足类动物体内的圆环病毒，它们对生态系统功能至关重要：Diporeia（在密歇根湖），在过去的20年里，在五大湖中，这种藻类的数量急剧下降;以及Peramphithoe femorata，它是美国西海岸受环境威胁的巨型海带Macrocystis pyrifera的主要消费者。几十年来，人们已经认识到病毒在水生态学和水地球化学中的重要性，但目前的研究主要集中在噬菌体和真核微生物中的病毒。后生动物是底栖生物地球化学的重要驱动因素，它们导致缺氧沉积物的生物灌溉、再悬浮、颗粒物沉降，促进沉积物向上覆沃茨的营养通量，并可能影响沉积物反硝化等海洋尺度过程。圆环病毒已被鉴定为甲壳动物病毒组合的常见成分，其中它们与宿主死亡率和种群下降密切相关，并且培养的圆环病毒导致节肢动物细胞死亡。因此，迫切需要研究病毒如何影响其甲壳类宿主的生态，以及这些影响如何反过来影响生态系统功能。端足类是海底生境重要的表生动物组成部分，它们消耗沉积的颗粒物质和水生植被，这反过来又影响其通过微生物降解转化为溶解的有机物质。反过来，它们的摄食活动刺激底栖矿化率，它们被更高的营养级消耗。因此，端足类动物在沿海和湖泊栖息地将微生物食物网与大型生物食物网联系起来。本研究以端足类感染的圆环病毒如何影响C在底栖生态系统中的通量，作为后生动物病毒如何影响水生生态系统生态地球化学的模型。这项研究将深入了解病毒如何影响水生生物地球化学，开辟了一个新的研究领域，以后生动物病毒在底栖生态系统。更广泛的影响：该项目已被设计为包括三个更广泛的影响活动。首先，它将涉及科学教师在纽菲尔德高中（纽约州纽菲尔德）和奥奈达湖地区高中直接参与和高需求的学生融入研究团队进行实验和实验室分析，最终在他们的研究活动介绍给他们的同龄人。其次，它将通过在康奈尔生物野外站的暑期实习吸引本科生，并在康奈尔大学的学年期间吸引本科研究人员参与实验并磨练科学演示技能。第三，它将开发广泛的网络外联工具，包括一个网站（包括实验的现场视图）和针对公众和K-12学生的社交媒体页面。最后，拟议的工作将提供深入了解脆弱的水生生态系统的生态。