Award: OCE-1830011

Cyanobacteria are critical components of microbial food webs in aquatic ecosystems. This project characterized, for the first time, the genetic diversity and population dynamics of small unicellular picocyanobacteria across the Laurentian Great Lakes (Intellectual Merit). The Great Lakes are a unique and vital ecosystem providing countless socioeconomic benefits. This project documented diverse microbial communities in the Great Lakes containing hundreds of species, that exhibit predictable patterns with water depth, season, and across lakes. Microbial communities in Lake Erie were found to be distinct from communities in other lakes. Microbial community structure is predominantly driven by local environmental conditions, rather than by geographic distance. Thousands of samples were collected aboard two research vessels, the R/V Lake Guardian and the R/V Blue Heron, greatly expanding the spatial and temporal coverage of previous datasets. Focusing on specific taxonomic and functional groups, the project identified and characterized novel lineages of picocyanobacteria and nitrifying Bacteria and Archaea, both important for nutrient cycling. New methods were developed for studying microbial communities using multi-laser flow cytometry, comparative metagenomics, and metaproteomics. New datasets were produced including DNA sequences, flow cytometry, and environmental parameters. The Broader Impacts of the project include training 1 postdoctoral fellow, 4 Ph.D. students including one female URM, 5 undergraduates, 1 postbaccalaureate trainee (female URM), and 1 high school student. Results were disseminated through numerous regional, national, and international conferences, published manuscripts, and research seminars. The project enhanced public understanding of the Great Lakes and microbial communities via the South Side Science Festival in Chicago and press coverage in the Chicago Tribune, Associated Press, and WBEZ Chicago. Last Modified: 01/12/2024 Submitted by: MaureenLColeman