Metagenomic characterization of the cyanobacterial harmful algal blooms in Lake Okeechobee

HCNSO Guy Harvey Oceanographic Center Nova Southeastern University

Lake Okeechobee (Lake O), a large shallow lake in south Florida, is an important resource. It is used for recreation and fishing, while also serving as flood protection for central and south Florida and a water supply to surrounding municipalities. While deemed “naturally” eutrophic, nutrient input due to human activity has increased substantially which has led to the reoccurrence of cyanobacterial harmful algal blooms (cyanoHABs) in the lake and surrounding tributaries that lead to the Gulf of Mexico and Atlantic Ocean. CyanoHABs have detrimental ecological impacts, while also being a public risk primarily due to the compounds that many of the dominating cyanobacterial species in blooms produce that are toxic to human and animals. We employed the use of high throughput sequencing to examine the microbial community dynamics in Lake O in order to develop a better biological understanding of the system. A temporal and spatial survey of Lake Okeechobee was performed by the collection of monthly water samples from 21 stations for DNA extraction. Seventy-four samples were chosen from April through September for metagenomic (“total environment, beyond a single genome”) sequencing, which captured the identities of the algal community and all associated microorganisms before, during and after algal bloom season. Metagenomes also allowed for characterization of the functional potential of the community and revealed potential for nutrient utilization, algal toxin production and degradation, and allelopathic interaction pathways. In combination with more traditional techniques, like microscopy, cell counts and water quality monitoring, these data will provide a holistic view of the potential biological processes occurring in Lake Okeechobee and associated waterways.