Formation of benthic cyanobacterial mats (BCMs) in marine environments is occurring frequently, partly driven by nutrient loading and climate change. Reports of BCMs occurring on both Florida coasts have increased, from mangroves to seagrass beds and corals, demonstrating a need to understand the diversity involved in the blooms of BCMs. As part of a continued monitoring of this environmental health threat, benthic proliferations were sampled on the Florida coasts between 2021 and 2022. Cyanobacterial mats were collected, eDNA was extracted, and the 16S rRNA of cyanobacteria were amplified using cyanobacterial specific primers. In addition to amplicon sequencing, isolation, characterization, and genome sequencing of select strains were performed. The homocytous filamentous Dapis, Okeania, Salileptolyngbya, and Sirenicapillaria dominated BCMs on the Gulf Coast of Florida. LC-MS/MS analyses revealed high concentrations of anatoxin-a, dihydroanatoxin-a and BMAA and presence of malyngamide C and cylindrospermopsin, within both the water column and mat material. In addition to known taxa, several novel taxa are currently being described including novel species of Nunduva and Rivularia, as well as novel genera. Results from this study indicate a need to further assess the spatial and temporal aspects of these blooms, in addition to their community structure, influencing factors and the production of toxic and bioactive compounds.

Primary Presenter: David Berthold, University of Florida (dberthold@ufl.edu)

Authors:

David Berthold, University of Florida  (dberthold@ufl.edu)

Forrest Lefler, University of Florida  (flefler@ufl.edu)

Jessica Moretto, University of Florida  (jessica.morettoa@ufl.edu)

Katherine Hubbard, FWC-FWRI  (Katherine.Hubbard@MyFWC.com)

Dail Laughinghouse, University of Florida  (hlaughinghouse@ufl.edu)