Metagenomics Reveals Spatial Variation in Cyanobacterial Composition, Function, and Biosynthetic Potential in the Winam Gulf, Lake Victoria, Kenya

The Winam Gulf (Kenya) is a vital resource that experiences prolific cyanobacterial harmful algal blooms (cyanoHABs). Bloom-forming cyanobacteria produce cyanotoxins, threatening human and environmental health, recreation, and fishing. However, cyanotoxin production in the gulf has not been linked to a specific type of cyanobacteria. We used DNA sequencing of whole microbial communities to track the species of cyanobacteria present across the gulf and investigate the genes responsible for the synthesis of known and novel toxins. Our results reveal Dolichospermum as the main bloom-forming cyanobacteria in the gulf, often co-occurring with a high abundance of toxigenic Microcystis. Over 300 unique gene clusters were found, with most predicted to encode the synthesis of uncharacterized molecules. These results provide initial insights into the diverse biosynthetic potential encoded by cyanobacteria in the Winam Gulf and underscore the need to further elucidate and investigate the effects of known and novel molecules produced in cyanoHABs in this region. This dataset consists of the metagenome assembled genomes (MAGs) associated with this publication by Hart et al.. Uploads of these data to NCBI are in progress.