Evaluation And Prediction Of Ecological Health In Tianjin Coastal Waters

The offshore area of Tianjin is located at the bottom of the Bohai Bay.The level of marine ecological health is the basis for supporting the marine economic development around the Bohai Sea.With the rapid development of marine economy in Tianjin,the increase of human activities in coastal areas,the continuous discharge of land-based pollutants into the sea,and the increase of offshore protection by sea related management departments,it is urgent to grasp the trend of marine ecosystem health level in Tianjin coastal waters.From the perspective of ecosystem health,this study introduces the concept of marine ecosystem health and the methods and application progress of evaluating marine ecosystem health.Combined with the ecosystem characteristics of Tianjin coastal waters,this study is based on the Ecosystem Investigation and monitoring data and relevant historical data of Tianjin coastal waters from 2008 to 2017,Through the evaluation of the ecological health status of the index data and the analysis of the time series of the index factors,a grey model in line with the Tianjin coastal waters is constructed to predict the ecological indicators,so as to evaluate the restoration of the Tianjin coastal ecosystem,in order to provide theoretical support for the scientific development of marine ecological protection and sustainable utilization of the Tianjin coastal waters,It provides a new exploration for the prediction method of marine ecological health level.The main results are as follows:1.Based on the "pressure-state-response(PSR)" framework model,the evaluation index system is constructed.A total of 22 indexes are selected to form the pressure layer,state layer and response layer.The weight is determined by analytic hierarchy process,and the integrated health index(IHI)is used to evaluate and analyze the ecological health status of Tianjin coastal waters from 2008 to 2017.The results show that the comprehensive health index in 2014 is the largest,the corresponding ecosystem is at the sub-health level,and the other years are at the health level.2.Based on the annual average data of Ecosystem Investigation and monitoring in Tianjin coastal waters from 2008 to 2017,a grey prediction model is constructed with a three-year cycle.The GM(1,1)model was tested.The test results showed that the posterior error test results of inorganic nitrogen(water quality),active phosphate(water quality),zooplankton diversity index and zooplankton species did not meet the requirements.Therefore,the residual error of the model was corrected.The results show that the accuracy grade of GM(1,1)model after residual correction is excellent,indicating that the final model has a good simulation effect on the index value.3.The research shows that according to the grey prediction model and integrated health index(IHI),the results of ecological health index in 2020 and 2023 are 1.101 and 1.150 respectively,ranging from 0.8 to 1.2,indicating that the marine ecosystem in Tianjin coastal waters will be at a healthy level in 2020 and 2023.The research shows that the ecological health evaluation results based on the "pressure-state-response(PSR)" framework model are basically consistent with the previous research results,indicating that the model can be applied;Through the test of GM(1,1)model and the analysis of the development trend of ecological health,it shows that the established grey model can be used for the prediction of indicators.Based on the prediction results of ecological health,the marine ecosystem in Tianjin coastal waters will be at a healthy level in 2020 and 2023.