Spatial and Temporal Resolution of Cyanobacterial Bloom Chemistry Reveals an Open-Ocean as a Talented Producer of Specialized Metabolites.

While the ecological role that sp. play in nitrogen fixation has been widely studied, little information is available on potential specialized metabolites that are associated with blooms and standing stock colonies. While a collection of biological material from a bloom event from North Padre Island, Texas, in 2014 indicated that this species was a prolific producer of chlorinated specialized metabolites, additional spatial and temporal resolution was needed. We have completed these metabolite comparison studies, detailed in the current report, utilizing LC-MS/MS-based molecular networking to visualize and annotate the specialized metabolite composition of these blooms and colonies in the Gulf of Mexico (GoM) and other waters. Our results showed that blooms and colonies found in the GoM have a remarkably consistent specialized metabolome. Additionally, we isolated and characterized one new macrocyclic compound from , trichothilone A (), which was also detected in three independent cultures of . Genome mining identified genes predicted to synthesize certain functional groups in the metabolites. These results provoke intriguing questions of how these specialized metabolites affect ecophysiology, symbioses with marine invertebrates, and niche development in the global oligotrophic ocean.