Studies On Early Warning Threshold Of Marine Resources And Environment Carrying Capacity Based On Ocean Health

The ocean is our country's blue territory,and it is an important strategic space for the development of marine economy,the construction of a powerful ocean country and the implementation of the strategic deployment of marine ecological civilization.With the reform and opening up and the continuous development of economy,the marine environment has been seriously polluted and the ocean health has been damaged.Monitoring and early warning of carrying capacity of marine resources and environment is an important management means to optimize marine protection and development of marine spatial pattern,and also an important component of monitoring and early warning of carrying capacity of marine resources and environment in China.In order to comprehensively promote the construction of ecological civilization system,ensure the level of ocean health and follow the concept of sustainable development,it is necessary to strengthen the research on relevant theories,technical methods and pilot sea areas of marine resources and environmental carrying capacity,and form a scientific and effective early warning mechanism system,which is the basis and guarantee of promoting the construction of long-term early warning mechanism of marine resources and environmental carrying capacity.Based on the above situation,this paper discussed the methods and cases of early warning.There are four main methods of early warning: single early warning,state early warning,process early warning and target early warning.According to the analysis of several early warning cases,it could be seen that the establishment of early warning model can not be separated from the determination of early warning baseline value,that is,the determination of threshold.Threshold has been widely used in various aspects.The ecological threshold was studied in this paper.The types of ecological thresholds are mainly divided into two types: ecological thresholds and ecologicalthresholds.There are three methods to determine the ecological threshold: field observation,statistical analysis and model simulation.Among them,the Gauss model method is included in the model simulation method.This method was an important theoretical basis for this study.Yueqing Bay is one of the most important bays in China.Taking Yueqing Bay as an example to study the sea area has practical significance.It is hoped that the study of Yueqing Bay will provide some reference value for the early warning threshold of marine resources and environmental carrying capacity.Three research cases in Yueqing Bay were selected in this paper,which were studies on the ecological threshold of phytoplankton to the environmental gradient of salinity in the Yueqing Bay,studies on the ecological thresholds of Labidocera euchaeta to the gradient of salinity in the Yueqing Bay and the marine water quality criteria of N&P and application in Yueqing Bay.The first two cases were studied from the biological point of view in Yueqing Bay.The biomass of phytoplankton and Daphnia acuminata in Yueqing Bay were selected as biological indicators,and salinity was regarded as an environmental factor.The ecological thresholds of phytoplankton and Daphnia acuminata under salinity gradient were obtained by curve fitting using Gauss model method.The optimum threshold point(u)could be obtained by the method of Gauss model.At the same time,the optimum ecological threshold interval([u-t,u+t])and ecological threshold interval([u-2t,u+2t])could be obtained.And u is the value of the environmental gradient when the biological index reaches the maximum value,t is a tolerance of the environmental gradient value.The early warning was divided into four levels:the value of environmental factors in the range of optimum ecological threshold intervals was blue warning;The value of environmental factors in the range of ecological threshold intervals and beyond the range of optimum ecological threshold intervals was yellow warning;the value of environmental factors beyond the range of ecological threshold intervals and not reaching the death line was orange warning;the value of environmental factors outside the death line was red warning.For example,in the case of ecological threshold of phytoplankton under salinity gradient in Yueqing Bay,the corresponding results of ecological threshold and early warning level were that the early warning level was blue when salinity value was within [25.24,27.00];yellow when salinity value was outside [25.24,27.00] and within [24.36,27.88];orange whensalinity value was less than 24.36 or more than 27.88 and did not reach the death line;and red when salinity value was outside the death line.Another case was the determination of water quality factors in Yueqing Bay and the classification of water quality grades.Threshold values were obtained in all three cases,although the methods used were different.Then,different methods were used to classify the early warning level,which was based on the established Gauss model and existing standards.However,in this study,we mainly discussed the method to determine the early warning threshold of resource carrying capacity based on Gauss model,and took phytoplankton(cell density)and zooplankton(Labidocera euchaeta)as examples to carry out the application of specific cases in Yueqing Bay,hoping to apply the Gauss model method to the key content of the early warning threshold of the carrying capacity of marine resources and environment,including the determination of the threshold and the division of the early warning level.In theory,this paper divided the early warning level of carrying capacity of resources and environment into four levels according to the early warning threshold,and taked Yueqing Bay as an example for concrete application.Although the authority of this method needed to be further studied.Through monitoring and early warning of the carrying capacity of marine resources and environment,the real-time assessment of ocean health could be realized,so that problems could be found and solved in time,which could play a good guiding role in marine ecological restoration and ensure the sustainable development of marine ecosystems.