Collaborative Research: Role of Nutrient Limitation and Viral Interactions on Antarctic Microbial Community Assembly: A Cryoconite Microcosm Study

合作研究：营养限制和病毒相互作用对南极微生物群落组装的作用：冰石微观世界研究

• 批准号: 2137377
• 负责人: Anna Bergstrom
• 金额: $ 3.66万
• 依托单位: Boise State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2137377&HistoricalAwards=false
• 关键词: Collaborative; Research; Role; Nutrient; Limitation; Collaborative; Research; Role; Nutrient; Limitation

Cryoconite holes are sediment-filled melt holes in the surface of glaciers that can be important sites of active microbial life in an otherwise mostly frozen and barren landscape. Previous studies in the McMurdo Dry Valleys, Antarctica suggest that viral infections of microbes, and a general lack of fertilizers (i.e., nutrients), may be important factors shaping the development and functioning of microbial communities in cryoconite holes. The researchers propose an experimental approach to understand how nutrient limitation affects diversity (number of species) and overall abundance of microbes, and how the diversity and abundance of microbes in turn affects the diversity, abundance, and infection type of viruses that parasitize the microbes in cryoconite sediments. The researchers will use sediments previously collected from Antarctic glaciers that have varying concentrations of viruses and nutrients, to set up a nutrient-addition experiment to determine how nutrients affect microbial and viral population dynamics. The results will deepen our understanding of how microbial communities in general are shaped by nutrients and viruses and give new insights into the functioning of viruses in extremely cold environments. The researchers will publish their findings in scientific journals and will share their discoveries with K-12 students from rural schools in collaboration with the Pinhead Institute and will connect undergraduate students from under-represented minorities to polar research through participation in the university’s Science, Technology, Engineering & Mathematics Routes Uplift Research Program. Outreach will be achieved through videos produced and distributed by a professional science communicator. The research advances a National Science Foundation goal of expanding fundamental knowledge of Antarctic systems, biota, and processes by utilizing the unique characteristics of the Antarctic region as a science observing platform. The Principal Investigators propose an experimental approach to understand how nutrient limitation affects microbial diversity and abundances and their cascading effects on virus diversity, abundance, and mode of infection (lysis vs. lysogeny) in Antarctic cryoconite holes. Cryoconite holes are ideal natural microcosms for manipulative studies, not available in other cryospheric ecosystems. The PIs will use previously collected cryoconite from across a gradient of both viral diversity and nutrient levels to address questions about key limiting nutrients and microbial-viral community dynamics in cryoconite sediments. Nutrient manipulation experiments will be conducted in a growth chamber that closely approximates the light and temperature regime of in situ cryoconite holes to test three core hypotheses: (1) phosphorus availability limits microbial productivity and abundance in cryoconite holes; (2) relaxing nutrient limitation in cryoconite from low-diversity glaciers will increase species diversity, leading microbial communities to resemble those found on more nutrient-rich glaciers; (3) relaxing nutrient limitation will increase the diversity and abundance of viruses by increasing the availability of suitable hosts, and decrease the prevalence of lysogenic infections. By manipulating nutrient limitation within a realistic range, this project will help verify hypothesized phosphorus limitation of Antarctic cryoconite holes and will extend understanding of the connections between nutrients, diversity, and viral infection dynamics in the cryosphere more generally. A better understanding of these dynamics in cryoconite sediments improves the ability of scientists to forecast future impacts of environmental changes in the cryosphere.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

冷冻岩孔是冰川表面上充满沉积物的熔体孔，在原本冻结和贫瘠的景观中，可能是活跃微生物寿命的重要部位。先前在McMurdo Dry Valleys的研究，南极表明，微生物的病毒感染以及普遍缺乏肥料（即营养素）可能是塑造冷冻岩孔中微生物群落发展和功能的重要因素。研究人员提出了一种实验方法，以了解营养限制如何影响多样性（物种数量）和微生物的整体丰度，以及微生物的多样性和丰度如何影响降低冷冻岩沉淀物中微生物的病毒的多样性，丰度和感染类型。研究人员将使用先前从具有不同浓度的病毒和养分的南极冰川收集的沉积物来建立营养成分实验，以确定养分如何影响微生物和病毒种群动态。结果将加深我们对一般微生物群落如何受营养和病毒塑造的理解，并在极度冷的环境中对病毒的功能进行新的见解。研究人员将在科学期刊上发布他们的发现，并将与Pinhead Institute合作与来自粗糙学校的K-12学生分享他们的发现，并通过参与大学的科学，技术，工程，工程和数学路线上的研究计划，将从代表不足的少数群体与极地研究联系起来。外展将通过专业科学沟通者制作和分发的视频来实现。该研究通过利用南极地区的独特特征作为科学观察者平台来促进国家科学基金会的目标，即扩大南极系统，生物群和过程的基本知识。首席研究人员提出了一种实验方法，以了解营养限制如何影响微生物多样性和丰富性及其对南极冷冻石孔中病毒多样性，丰度和感染模式（裂解与裂解）的级联影响。冷冻岩孔是用于操纵研究的理想自然缩影，在其他Cryosphere生态系统中不可用。 PI将在病毒多样性和营养水平的梯度上使用先前收集的冷冻岩来解决有关限制养分和微生物 - 病毒社区动力学的问题。营养操纵实验将在生长室中进行，该生长室紧密近似于原位冷冻岩孔的光和温度状态，以检验三个核心假设：（1）磷的可用性限制了冷冻岩孔中的微生物生产率和抽象； （2）低多样性冰川中的冷冻岩的放松营养限制将增加物种多样性，导致微生物群落类似于在富含营养的冰川上发现的物种多样性。 （3）放松的养分限制将通过增加合适宿主的可用性并降低溶菌发生感染的患病率来增加病毒的多样性和抽象。通过操纵在现实范围内的营养限制，该项目将有助于验证假设的磷限制南极冷冻岩孔，并将更广泛地更广泛地了解养分，多样性和病毒感染动态之间的联系。对冷冻岩沉积物中这些动态的更好理解提高了科学家预测Cryosphere环境变化的未来影响的能力。该奖项反映了NSF的法定任务，并且认为值得通过基金会的知识分子优点和更广泛的影响审查标准通过评估来获得支持。