河道生态系统特征及其自净化能力研究现状与发展

River ecosystems and their self-purification capability:research status and challenges

河道生态系统包括河道水体和河岸带两大部分,具有净化水体、降低污染物浓度的功能。研究河道生态系统的自净化能力对河道生态系统的健康评价及水环境管理具有重要的意义。目前该领域的研究主要侧重于两个方面:一方面是运用水质模型的方法模拟评价河道水体的自净化能力,另一方面则是研究河岸植被缓冲带对净化水体的作用。系统总结了目前研究的特点与不足,指出了今后应该重视的研究领域,主要包括:(1)应加强研究陆地生态系统空间异质性对河道自净化能力的影响研究;(2)需要系统解剖河道剖面形态结构与空间布局对河道水质自净化能力的影响;(3)重视面向外部复杂环境的参数获取方法的研究;(4)综合河岸生态系统与河道水体生态系统,系统研究非点源污染在陆-水迁移和水体运移中河道生态系统自净化能力的时空变化特征,从而为开展河道生态系统健康评价,河道生态系统管理提供科学的依据。

A river ecosystem comprises stream channels and adjacent riparian zones. It provides some significant ecosystem services through diluting pollution concentrations and purifying stream waters. Therefore, studies on the self-purification capability of a fiver ecosystem are critical for ecosystem health assessment and environmental management. Two major research approaches have been developed to study the fiver ecosystem structure and services, with one focusing on the use of water quality models to assess the self-purification capability of a river ecosystem and the other studying the roles of riparian vegetation buffers in purifying stream waters. Based on extensive literature reviews, we have identified several areas that need further research. Firstly, more research should be carried out to investigate how terrestrial landscape heterogeneity and fiver channel morphodynamics could affect the self-purification capability of a river ecosystem. Secondly, more emphases should be paid upon the methodology development that can enhance environmental parameter extraction for implementing water quality predictive models in complex landscapes. Lastly, a significant area for continuing research is the systematic study on non-point pollutants transporting from land to water and within stream waters and the resultant spatio-temporal characteristics of the self-purification capability of a river ecosystem; such a study can provide useful insights for river ecosystem assessment and management.