基于熵权TOPSIS模型的厦门湾海洋环境质量20年时空变化评估

Spatiotemporal changes assessment in marine environmental quality of Xiamen Bay over the past 20 years based on the Entropy-Weighted TOPSIS model

良好的海湾环境质量对沿岸生态系统和可持续发展具有重要意义,厦门湾在2000-2020年期间开展了大量综合整治和生态修复工作,但尚未有研究系统揭示海洋环境质量在20年间的变化。本研究基于熵权TOPSIS模型,选取溶解氧、无机氮和活性磷酸盐3个海水水质指标及有机碳和硫化物2个沉积物指标,评估了厦门湾2000、2010、2020年3个时间节点的海洋环境质量及其时空变化。评估结果显示,所有指标的评估值在2000-2020年间均出现了上升,上升幅度为1.2%~11.8%,整体上看水质指标的改善幅度大于沉积物指标,其中沉积物的有机碳指标改善幅度最小;绝大部分指标的标准偏差随时间推移减小,提示海洋环境质量更趋稳定。在时间趋势上,海洋环境质量综合指数整体持续上升,环境质量得到改善的海域面积占比45.42%,仅有14.67%的海域环境质量略有下降,主要集中在九龙江口;在空间分布上,3个时期的综合指数均呈现出西低东高的趋势,表明东部的海洋环境质量长期优于西部。斯皮尔曼相关性分析结果显示,厦门湾海洋环境质量变化的主导因子为无机氮、活性磷酸盐和硫化物。本研究为了解厦门湾海洋环境质量的时空变化提供了重要参考,研究结果可作为该地区海洋生态环境管理和保护的科学依据。

The quality of estuarine environments is of paramount importance to coastal ecosystems and sustainable development.Xiamen Bay has undertaken extensive comprehensive restoration and ecological rehabilitation efforts in 2000-2020,however no studies have systematically revealed the changes in marine environmental quality over these twenty years.Used time-series data from time nodes of 2000,2010 and 2020,5 indexes,dissolved oxygen,inorganic nitrogen,and reactive phosphates in the seawater,organic carbon and sulfides in the sediments were selected as indexes to assess the spatiotemporal changes of the marine environmental quality based on the entropy-weighted TOPSIS model.Results indicate that all indexes increased at rates of 1.2%to 11.8%from 2000 to 2020,overall,the improvement in water quality indexes was greater than that of sediments,of which the organic carbon index showed the least improvement.The standard deviations of most indexes decreased with time,suggesting a trend of more stable marine environmental quality.The comprehensive marine environmental quality index exhibited an increasing trend with time with 45.42%of the areas showing improved environmental quality,while only 14.67%areas went slight declining mostly concentrated in Jiulong River Estuary.Spatially,the comprehensive index in all three time nodes showed lower in the west and higher in the east,indicating that the eastern part of Xiamen Bay had consistently better marine environmental quality than the western part.Spearman correlation analysis indicates that the dominant driving factors changing the marine environmental quality of Xiamen Bay water are inorganic nitrogen,active phosphate and sulfides.This study provides valuable insights into the spatiotemporal changes of marine environmental quality and offers a scientific basis for marine ecological environment management and protection in Xiamen.