PS 37-31 - Community Structures of Benthic Cyanobacteria Across Various Rivers in the United States

Abstract: Benthic cyanobacteria present in streams and rivers are getting more attention due to their toxin production, but our understanding of the various communities of benthic cyanobacteria in the US is largely limited. While Harmful Algal Blooms (HABs) in lakes are usually predominately composed of a singular dominant strain of planktonic cyanobacteria, benthic cyanobacteria are highly diverse and can develop mats on various substrates along riverbeds. Thus, this makes it difficult to identify and characterize benthic cyanobacterial community structures as well as develop assays to detect specific benthic cyanobacteria. The purpose of this study was to use 16S amplicon sequencing to characterize the community structures found in rivers across the United States. These locations were made up of rivers from the northwestern, northeastern, and the midwestern parts of the country. Preliminary results indicated the prevalence of Tychonema and Sericytochromatia cyanobacterial genera across each of the three locations along with various additional potential toxin producing taxa (Microceria, Pseudoanabaena, Phormidium). Non-metric multidimensional scaling (NMDS) showed distinct community structure clustering between benthic and water column samples and among benthic samples from each location implying an overlap in community abundance despite being from different regions. These community results along with other future quantitative analyses can help us better understand the dominance and composition of potential toxic benthic cyanobacteria and aid in the development of universal assays for detecting them across waterbodies in the US. In conclusion, these results highlight the importance of understanding the community diversity of benthic cyanobacteria in the US and the potential human and ecological health risks associated with benthic HABs in lotic water bodies.

Keywords: Benthic cyanobacteria, 16s rRNA gene, community structure, river, stream