Harmful Algal Blooms in Cayuga Lake, Ny : From Microbiome Analysis to Edna Monitoring

The global increase in harmful algal blooms (HABs) has become a growing concern over the years, and New York State (NYS) is no exception. The Finger Lakes region in NYS has been identified as a hotspot for HABs, with Cayuga Lake having the highest number of blooms reported. The Cayuga Lake HABs Monitoring Program has been tracking cHABs (dominant bloom taxa, chlorophyll A, and microcystin levels) since 2018. Analysis of data from 2018-2020 revealed that the genus Microcystis and Dolichospermum dominated cHABs in Cayuga Lake, with a strong correlation between microcystin and chlorophyll A concentrations when Microcystis was present. However, limited research has been conducted on the microbiome of HABs in this region. In this study, the microbiome of HABs in the Cayuga Lake was surveyed and compared with non-HAB baseline samples. Using 16S rDNA community analysis, common bloom-forming cyanobacteria, including Dolichospermum, Planktothrix, Microcystis, Cylindrospermopsis, Nodularia, and Trichodesmium, were identified, with Microcystis being the dominant taxa in high toxin blooms. Further, this study evaluated the ability of Microcystis mcyA qPCR to detect elevated levels of potential toxigenic Microcystis in water samples using both benchtop and handheld qPCR devices. The results showed good performance of the qPCR assay as a screening for high toxin versus low/no toxin blooms, with low specificity attributed to sub-toxic samples that tested positive. Additionally, the handheld qPCR device holds potential for in-field rapid (<1 hour) screenings for high toxin blooms. This study provides insights into the microbiome of HABs in the Cayuga Lake and offers a potential tool for rapid screening of high toxin blooms