Collaborative Research: Teasing apart coexisting cyanobacteria in the Laurentian Great Lakes

劳伦斯五大湖拥有地球上20%的地表淡水和84%的美国地表淡水，构成了地球上最大的淡水生态系统。它们提供重要的生态系统服务，如渔业和娱乐，并作为4000万人的饮用水来源。近几十年来，五大湖经历了重大的环境变化，例如营养物质污染和入侵物种，改变了水化学和食物网络结构。特别是，食物网的基础发生了戏剧性的变化。一年一度的春季浮游植物水华在密歇根湖和休伦湖基本消失，而有毒的蓝藻水华在伊利湖增加。构成五大湖食物网基础的微生物知之甚少，在调节水质和生态系统生产力方面发挥着关键作用。这个项目描述了劳伦斯五大湖上的单细胞蓝藻的特征，以了解它们的遗传多样性和生态。研究人员正在与芝加哥南侧的当地高中合作，开发关于微生物在五大湖健康中的作用的教学模块。当地高中教师将参与设计有关水生微生物生态学的课程，目标是提高五大湖的识字率和芝加哥南部贫困和多样化社区的STEM参与度。在劳伦斯五大湖的一些地区，微囊藻贡献了高达50%的初级生产。然而，人们对它们的种群结构和动态以及影响它们丰度和活动的因素知之甚少。在面临快速环境变化的情况下，了解对微囊藻多样性和功能的控制对于开发五大湖的预测性生物地球化学模型至关重要。最近在五大湖中发现了共存的多个微蓝细菌系统发育类群，该项目描述了它们的遗传、生理和生态多样性。结合使用流式细胞术和分子测序方法，正在对不同的种群进行量化，跨越湖泊、深度和季节，并使用比较基因组学来揭示途径和基因如何分布在分类群和栖息地之间。定量转录组学和蛋白质组学正被用于诊断环境对基因表达的控制，并评估不同种群的相对活动。正在进行的时间序列数据和存档样本正在与R/V蓝鹭号上的定向采样相结合。这个项目通过生成第一张关于五大湖微生物食物网的生态系统中苦味酸细菌多样性的系统图片来促进我们的知识。这个奖项反映了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。

The Laurentian Great Lakes hold 20% of our planet's surface freshwater and 84% of US surface freshwater, comprising the largest freshwater ecosystem on Earth. They provide critical ecosystem services such as fisheries and recreation, and serve as the drinking water source to 40 million people. In recent decades, the Great Lakes have experienced significant environmental changes, such as nutrient pollution and invasive species, that have altered water chemistry and food web structure. In particular, the base of the food web has changed dramatically. Annual spring phytoplankton blooms have largely disappeared in Lakes Michigan and Huron, while toxic cyanobacterial blooms have increased in Lake Erie. The microorganisms that make up the base of the food web in the Great Lakes are poorly understood and play critical roles in regulating water quality and ecosystem productivity. This project characterizes single-celled cyanobacteria across the Laurentian Great Lakes to understand their genetic diversity and ecology. The investigators are working with local high schools on Chicago's south side to develop teaching modules about the role of microorganisms in the health of the Great Lakes. Local high school teachers will be engaged to design lessons about aquatic microbial ecology, with the goal of increasing Great Lakes literacy and STEM participation in Chicago's impoverished and diverse south side communities. Picocyanobacteria contribute up to 50% of primary production in some portions of the Laurentian Great Lakes. However, little is known about their population structure and dynamics, or about factors shaping their abundance and activity. Understanding controls on picocyanobacterial diversity and function is crucial for developing predictive biogeochemical models for the Great Lakes in the face of rapid environmental change. Multiple phylogenetic groups of coexisting picocyanobacteria in the Great Lakes have recently been identified, and this project characterizes their genetic, physiological, and ecological diversity. Using a combination of flow cytometry and molecular sequencing approaches, distinct populations are being quantified across lakes, depths, and seasons, and comparative genomics is being used to reveal how pathways and genes are distributed across taxa and habitats. Quantitative transcriptomics and proteomics are being used to diagnose environmental controls on gene expression and to assess the relative activity of distinct populations. Ongoing time series data and archived samples are being combined with targeted sampling aboard the R/V Blue Heron. This project advances our knowledge of the Great Lakes microbial food web by generating the first systematic picture of picocyanobacterial diversity in this ecosystem.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.