Delineation,Inspection And Application Of Ecological Province In Eastern China Seas Based On The Dynamic Clustering Method

In order to understand the environmental conditions and the change process of the Eastern China Seas,so as to effectively guide the control and utilization of the environmental ecology,this paper uses Oceanographic Data Integrated Tool(ODIT,Registration NO: 2016SR380531)with independent intellectual property rights to screen a large number of valid data from the database of 28 voyages in the past 30 years,about 52 thousand chlorophyll concentration data.Referring to the large data clustering partitioning method and applying the K-mean method,the following datas are clustering analyzed,including the sea surface temperature(SST),in situ sea surface chlorophyll concentration(Chl),water depth(Dep),longitude(Lon)and latitude(Lat)of the Eastern China Seas.The appropriate cluster number has screened and validated by comparing the biogeochemical parameter statistical results and the ratios between largest group size and the smallest group size(Smax/Smin)of each cluster results.The results show: when the partition number(cluster number)is 6,the differentiation degree of each clustering geochemical parameters of the subdivision is slightly higher than that of partition number 5,and it has higher regional heterogeneity;but when the cluster number is not less than 6,the newly added partition feature is mainly the relatively independent small scale frontal surface;when the cluster number is less than 6,the scale of each habitat reflected is more similar,especially,the uniformity of each partition is the best when the cluster number is 5.Compared with the consistency between the sea area distribution and the corresponding water mass distribution,spatial similarity between the two is found better,that is,the partition of clustering 5 can clearly indicate the distribution scale of the Bohai Sea-Yellow Sea mixed water mass,the Yellow Sea(mixed)water mass,Changjiang diluted water,the denatured water in the shelf of the East China sea and Kuroshio Current.In order to explore the differences of primary productivity structure in cluster 5 of each partition,the paper establishes the relationship module of each partitions between the chlorophyll concentration different size-fractionated chlorophyll and total chlorophyll.The results showed that there was a significant linear correlation(R2 > 0.6)between the chlorophyll value of the Net-Chl,Nano-Chl and the total chlorophyll.The correlation between the estimated chlorophyll concentration and in situ chlorophyll concentration was analyzed,which found that the estimated values of Net-Chl,Nano-Chl and Pico-Chl were in good agreement with the measured values(0.88 and 0.47 for R2 in winter,0.86 and 0.57 for R2 in summer respectively).The chlorophyll concentration equation was used to estimate chlorophyll concentration in Eastern China seas,and the results showed that in Eastern China Seas,the contribution of Net-,Nano-and Pico-phytoplankton to total chlorophyll is relatively consistent in most of the winter sea areas,and the entire Eastern China Seas is dominated by Nano-phytoplankton;The Eastern China seas in summer,the Net-phytoplankton dominated in coastal and estuarine areas,while the Pico-phytoplankton dominated in the open sea,and the contribution of Nano-phytoplankton to total chlorophyll is similar in the whole Eastern China seas.The relationship between the size structure of phytoplankton and fishery resources was also analyzed.The results showed that partitions of Net-Chl with high values and higher contribution rates was conform with the distribution of the main feeding ground,spawning ground and nursering ground in the Eastern China Seas,which showed that the distribution of Net-Chl was more important to marine fishery resources,and had potential indicative role for fishing grounds.Based on the dynamic biogeochemical zoning theory put forward by predecessors,a new method for the ecological regionalization of the Eastern China Seas,and a relatively reasonable number of regionalization and ecological characteristics of each region are put forward in this paper.The research results can be used to master the dynamic changes of the Eastern China Seas by using remote sensing data,providing reference for monitoring and regulation of water environment,and providing basic data for marine fishery resources assessment.