基于PSR模型和层次分析法的渤海湾天津近岸海域富营养化评价

Eutrophication evaluation of Tianjin coastal waters in Bohai Bay based on PSR model and analytic hierarchy process

随着近几年经济快速发展,人们对海洋资源开发和利用的程度不断加大,导致人类活动对海洋生态系统产生了一些负面效应,其中近岸海域日益严重的富营养化问题显得尤为突出,因此,开展近岸海域水体的富营养化评价就显得尤为重要。本文在参考国内外第二代富营养化模型的基础上,筛选出具有代表性的11项指标,构建基于PSR模型的天津近岸海域富营养化评价指标体系。采用层次分析法确定各项指标的权重值,按照评价标准对指标进行分类赋分,最后采用综合指数法对2015—2017年的天津近岸海域富营养化水平进行评价,并运用EI法和NQI法对富营养化评价结果进行验证。本文将富营养化状态分为四个等级,以60分为富营养化分界线,评价结果显示近三年(2015—2017)渤海湾天津近岸生态监控区海域水体处于富营养化状态(富营养化评价得分分别为58.3分、53.0分、57.7分,均低于60分),与EI法和NQI法评价结果一致。说明近年来人类行为已对渤海湾天津近岸海域生态系统产生负面影响,本次评价结果显示近三年天津近岸海域水体富营养化程度较高。

With the rapid economic development, the increasing level of human exploitation and utilization of marine resources has led to some negative effects on marine ecosystems in recent years. The growing eutrophication problem in coastal waters is particularly prominent. Therefore, it is particularly important to carry out eutrophication assessment of water bodies in coastal waters. Based on the reference of the second generation eutrophication model at home and abroad, this paper screens 11 representative indicators and constructs the eutrophication evaluation index system of Tianjin coastal waters based on the PSR model. The analytic hierarchy process is used to determine the weight value of each index, and the index is classified according to the evaluation criteria. Finally, the comprehensive index method is used to evaluate the eutrophication level of Tianjin coastal waters from 2015 to 2017. The results of eutrophication evaluation were verified by EI method and NQI method. In this paper, the eutrophication state is divided into four grades, and the eutrophication boundary is determined by the score of 60. The evaluation results show that in the past three years(2015—2017), the water body in the coastal ecological monitoring area of the Bohai Bay is in eutrophication.(The eutrophication evaluation scores were 58.3, 53.0, and 57.7, respectively, in each year all lower than 60), which was consistent with the EI and NQI evaluation results. This indicates that human behavior has had a negative impact on the offshore ecosystem of the Bohai Bay in recent years. The results of this evaluation show that the eutrophication of Tianjin’s coastal waters is relatively high in the past three years.