| Abstract: | Using the SAS software, the data of environmental factors vs. red tide biomass were analysed during the process of Skeletonema costatum red tide which broke out in the Changjiang Estuary on June 9～15, 1990. The results of the multivariate statistical analysis show that the environmental factors are similar in their developing and maintenance periods and that the values of environmental factors begin to be restored to normal levels during the disappearing period.The results obtained from using the methods of correlation, variable cluster and main component analyses are basically identical. The important factors contributing to the occurrence of this red tide are atmospherical pressure, water temperature, salinity, pH, No3-, -N, Po43--P and Fe, among which,salinity, Fe and PO43--P are the leading factors which have triggered the occurrence of the red tide as determined by the step-by-step regression analysis. Meanwhile, the linear discrimination functions have been established for the red tide. The environmental factor data of another occurring process of Skeletonema costatum red tide in the Changjiang Estuary have been chosen for red tide discrimination with satisfactory results. |
