Since 2002, blooms of Alexandrium catenella sensu Fraga et al. (2015) and paralytic shellfish toxicity events have occurred almost yearly in Osaka Bay, Japan. To better understand the triggers for reoccurring A. catenella blooms in Osaka Bay, phytoplankton community was monitored during the spring seasons of 2012–2015. Monitoring was performed using massively parallel sequencing (MPS)-based technique on amplicon sequences of the 18S rRNA gene. Dense blooms of A. catenella occurred every year except in 2012, however, there was no significant correlation with the environmental parameters investigated. Plankton community diversity decreased before and middle of the A. catenella blooms, suggesting that the decline in diversity could be an indicator for the bloom occurrence. The yearly abundance pattern of A. catenella cells obtained by morphology-based counting coincided with the relative sequence abundances, which supports the effectiveness of MPS-based phytoplankton monitoring.
KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We thank Dr. Kyoko Yarimizu, National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, for critical reading of the manuscript and encouragement during this study. A. Kondo and R. Kubota are thanked for their help with the molecular work. This work was supported by a Grant-in-Aid (Marine Metagenomics for Monitoring the Coastal Microbiota) by the Ministry of Agriculture, Forestry, and Fisheries of Japan; a Grant-in-Aid for Scientiﬁc Research (Kiban-B) by the Japan Society for the Promotion of Science (Grant number:25292130); and a Grant-in-Aid by the Japanese Society for the Promotion of Science Fellows (Grant number: 02523180 and PE18028). [CG]