Temporal shifts of cyanobacterial communities at different sites of Nakdong River in Korea
The blooms of cyanobacteria by eutrophication or climate changes and the investigation of cyanobacterial community changes in freshwater environments are critical for the management of drinking water. We investigated the cyanobacterial communities from May to October, 2012 along six sites at Nakdong River in South Korea using high-throughput sequencing techniques and compared them with various geochemical factors at sampling sites. Diverse genera (total of 175 genera) within cyanobacteria were detected and the changes of their compositions were analyzed in this study. Genus of Prochlorococcus was predominated in May samples and especially site 1 (upstream of river), while the relative abundance of Microcystis and Anabaena were increased with warming water temperature. The relationship between cyanobacterial community and environmental factors were analyzed by Cannonical Correlation Analysis (CCA), and the correlation of harmful cyanobacteria and significant chemical factors were analyzed by Non-metric Multi-Dimensional Scaling (NMDS) ordination. The correlated environmental factors with relative abundance of Microcystis were same as those of Aphanizomenon, and the correlated factors with Anabaena were various. Various environmental factors were influenced to the changes of cyanobacterial communities in river. The obtained results in this study could be helpful to manage freshwater environment and maintain the quality of drinking water.