ANT LIA: Collaborative Research: Genetic Underpinnings of Microbial Interactions in Chemically Stratified Antarctic Lakes

第一部分：非技术描述：微生物群落不仅仅是科学的好奇心。微生物是地球上进化和生化多样性的最大来源。它们是碳、氮、磷和其他元素在生态系统中循环的主要媒介。尽管微生物在生态系统功能中很重要，但在食物网络模型和营养循环中，微生物仍然普遍被忽视。此外，微生物并不是孤立地生活：它们的生长和新陈代谢受到与其他微生物复杂相互作用的影响。该项目将重点研究南极湖生态系统中微生物群落的生态、活动和作用。该团队将描述微生物相互作用的遗传基础，以及环境梯度(例如光线、营养物质、氧气、硫磺)和季节(例如夏季与冬季)对麦克默多干谷地区泰勒河谷弗莱克塞尔湖和邦尼湖微生物网络的影响。最后，该项目通过包括本科生和研究生、一名博士后研究员和一名中学教师参与实验室和实地研究活动，进一步实现了NSF培养新一代科学家的目标。这一伙伴关系将涉及若干其他外联培训活动，包括访问教室和社区活动、参与社交媒体平台和网络研讨会。第二部分：技术描述：极地南极干旱山谷生态系统的生态系统功能取决于物理化学环境因素(如光、养分、氧、硫)、一年中的时间(如夏季与冬季)和微生物之间复杂的生物地球化学相互作用。微生物网络的复杂性可能因特定的非生物因素而异，这对生态系统在环境变化威胁下的脆弱性和复原力具有重要影响。该项目将评估生物地球化学因素对南极两个冰盖湖泊中微生物相互作用和网络复杂性的影响。这项研究将由三个主要目标构成：1)从丰富的空间和时间数据集推断正向和负向相互作用，并利用各种分子方法调查生物地球化学梯度对微生物网络复杂性的影响；2)利用流式细胞术、单细胞分选和显微镜直接观察微生物真核生物与其伙伴之间的相互作用；以及3)利用元基因组学建立特定相互作用的代谢模型。来自扩增子测序、元组学和单细胞基因组方法的结果将被整合在一起，以绘制特定的微生物网络复杂性图，并确定相互作用和代谢活动对不同季节湖泊生物地球化学趋势的作用。这些研究对于确定网络复杂性与未来气候条件之间的关系至关重要。本科生研究人员将从一个有吸引少数族裔代表不足的记录的REU项目和两个为少数族裔服务的机构招聘。为了进一步增加极地扫盲培训和教育影响，实地团队将包括一名教师，作为与成功的NSF资助的PolarTREC计划合作的一部分，并参与为公众出游而设计的活动。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Part I: Non-technical description: Microbial communities are of more than just a scientific curiosity. Microbes represent the single largest source of evolutionary and biochemical diversity on the planet. They are the major agents for cycling carbon, nitrogen, phosphorus, and other elements through the ecosystem. Despite their importance in ecosystem function, microbes are still generally overlooked in food web models and nutrient cycles. Moreover, microbes do not live in isolation: their growth and metabolism are influenced by complex interactions with other microorganisms. This project will focus on the ecology, activity and roles of microbial communities in Antarctic Lake ecosystems. The team will characterize the genetic underpinnings of microbial interactions and the influence of environmental gradients (e.g. light, nutrients, oxygen, sulfur) and seasons (e.g. summer vs. winter) on microbial networks in Lake Fryxell and Lake Bonney in the Taylor Valley within the McMurdo Dry Valley region. Finally, the project furthers the NSF goals of training new generations of scientists by including undergraduate and graduate students, a postdoctoral researcher and a middle school teacher in both lab and field research activities. This partnership will involve a number of other outreach training activities, including visits to classrooms and community events, participation in social media platforms, and webinars. Part II: Technical description: Ecosystem function in the extreme Antarctic Dry Valleys ecosystem is dependent on complex biogeochemical interactions between physiochemical environmental factors (e.g. light, nutrients, oxygen, sulfur), time of year (e.g. summer vs. winter) and microbes. Microbial network complexity can vary in relation to specific abiotic factors, which has important implications on the fragility and resilience of ecosystems under threat of environmental change. This project will evaluate the influence of biogeochemical factors on microbial interactions and network complexity in two Antarctic ice-covered lakes. The study will be structured by three main objectives: 1) infer positive and negative interactions from rich spatial and temporal datasets and investigate the influence of biogeochemical gradients on microbial network complexity using a variety of molecular approaches; 2) directly observe interactions among microbial eukaryotes and their partners using flow cytometry, single-cell sorting and microscopy; and 3) develop metabolic models of specific interactions using metagenomics. Outcomes from amplicon sequencing, meta-omics, and single-cell genomic approaches will be integrated to map specific microbial network complexity and define the role of interactions and metabolic activity onto trends in limnological biogeochemistry in different seasons. These studies will be essential to determine the relationship between network complexity and future climate conditions. Undergraduate researchers will be recruited from both an REU program with a track record of attracting underrepresented minorities and two minority-serving institutions. To further increase polar literacy training and educational impacts, the field team will include a teacher as part of a collaboration with the successful NSF-funded PolarTREC program and participation in activities designed for public outreach.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.