Characterization of the Cyanobacterial Harmful Algal Bloom Community in Hamilton Harbour, Lake Ontario

Little is known about the interspecific relationships between Cyanobacteria and heterotrophic microorganisms throughout Cyanobacterial harmful algal bloom (CyanoHAB) development mainly since most aquatic microorganisms are non-culturable in the laboratory. The culture-independent technique Terminal Restriction Length Polymorphism (T-RFLP) was used for fingerprinting of microbial community DNA collected from Hamilton Harbour water throughout the summers of 2014 and 2015. 454-tag encoded pyrosequencing and shotgun sequencing revealed the dominant prokaryotes and eukaryotes throughout each summer. Actinobacteria was the dominant bacterial phylum in June while Cyanobacteria and Proteobacteria were co-dominant from August-September. Shotgun data also revealed the microbial functional potentials. Cyanobacterial dominance was associated with a higher potential for nitrate/nitrite assimilation and nitrogen fixation in the late-summer. These results provide the first metagenomic characterization of the total CyanoHAB community in Hamilton Harbour. Correlations to physico-chemical parameters further provide insights for future management into which factors could be shaping the bacterial community throughout the summer.M.Sc