Phaeocystis globosaBloom Monitoring: Based onP. globosaInduced Seawater Viscosity Modification Adjacent to a Nuclear Power Plant in Qinzhou Bay, China

The mucus produced by the outbreak ofPhaeocystis globosain the adjacent waters of the Fangchenggang Nuclear Power Plant (FCGNPP) in China has blocked the entrance of the cooling water filtration system of the FCGNPP, and posed a threat to the safe operation of the FCGNPP. At present, there is no related research on whether the changes in seawater viscosity could be used as a new method for monitoring and providing early warning ofP. globosatide. During a complete red tide cycle, the temporal and spatial changes in the hydrological conditions (temperature, salinity, dissolved oxygen), chlorophyll-a(Chl-a), composition and abundance of phytoplankton, number and size ofP. globosecolonies, concentration of transparent exopolymer particles (TEP) and the seawater viscosity were measured in this study. The results indicate that there was an extremely significant negative correlation between the physical seawater viscosity eta(T,S)and temperature, and the correlation coefficient reached -0.998. The biological seawater viscosity eta(Bio)was positively correlated with the number ofP. globosacolonies, and the correlation coefficients is 0.747. Because the increase in phytoplankton abundance, especially during the outbreak ofP. globosaand a large amount of mucus produced by the colonies could significantly increase seawater viscosity, we suggest that biological factors were the main reasons for the increase in seawater viscosity. The eta(Bio)was completely consistent with the occurrence process ofP. globosabloom and could be used as a valuable index forP. globosabloom monitoring.