Relationship Between Red Tide Organisms And Environmental Factors And Potential Ecological Risk Assessment Of Red Tide Disaster In Haitan Strait Of Fujian

HAB is a common phenomenon about ecological environment anomaly in coastal waters.The relationship between red tide organisms and environmental factors and the potential ecological risk assess of red tide disasters in Haitan Strait were explored.Based on data of ecological and hydrological survey in Haitan Strait,the methods of Pearson correlation and CCA,and the theory of red tide disaster risk assessment,the relationship between red tide organisms and environmental factors was studied,the index system of red tide disaster assessment in Haitan Strait was constructed by using the method of AHP,and the weight was assigned by entropy method and coefficient of variation method.The scientific and credible assessment model was established,and the thematic maps of ecological risk disaster of Haitan Strait were obtained.This paper systematically answered three scientific questions:the species composition and spatial distribution characteristics of phytoplankton and red tide organisms in Haitan Strait,the relationship between red tide organisms and environmental factors,and the potential ecological risk of red tide disasters in Haitan Strait.One the one hand,a total of 102 species belonging to 4 classes and 52 genera were identified.49 species of red tide organisms were identified.Organisms of the widely distributed species with wide temperature and wide salt were mainly ecological group.And diatoms were absolute dominant in species number.However,the season of the most number of species was in summer.For cell density,the cell density of dinoflagellates was dominant in spring and that of diatoms in the other three seasons.For dominant species,the dominant species in spring were mainly Ceratium tripos and Noctiluca scintillans,while Skeletonema costatum was mainly the dominant species in the other three.Skeletonema costatum and Chaetoceros curvisetus were common dominant species and red tide organisms in Haitan Strait.T,S,p H,DO,TN,PO₄-P and E were found significantly related to red tide organisms by Pearson correlation.In addition,the ordination of the main environmental factors(S>T>p H>E>DO>TN>PO₄-P)was obtained by CCA analysis.On the other hand,the evaluation index system of the potential ecological risk of the red tide disaster was established,and then combination weighting method was used to endow indexes with weight.Thus,the potential ecological risk model of the red tide disaster was constructed,and the ecological risk zoning results of the red tide disaster in Haitan Strait were obtained.The results showed that the medium-high risk areas were mainly distributed in the north of the strait in spring.And the southern part of the strait was mainly at low risk.In summer,most of sea areas of the strait belonged to low-risk,while the high risk areas existed in the south of strait.In autumn,the risk levels were mainly low and medium,and the medium risk areas were mainly distributed in the northwest and southeast of the strait.In winter,high risk areas and highest risk areas were concentrated in the northwest or northeast part of the Haitan Strait.In addition,it was shown that the temporal and spatial characteristics of hazard of disaster-inducing factors had a good correlation with the distribution of red tide events for many years.Innovation points of this paper:The first innovation point is that the weighting method of ecological risk assessment index for red tide disasters was optimized.The combined weighting method of entropy weight method and coefficient of variation method was applied to the ecological risk assessment system of red tide disaster.The second innovation point is that the biological list of red tide was established,then found out the main environmental factors affecting the biological changes of red tide in Haitan Strait,and the index system and model of the potential ecological risk of red tide disaster in Haitan Strait were constructed,what's more,the ecological risk assessment of the red tide disaster in Haitan Strait was conducted for the first time.