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Phosphorus dynamics in groundwater-fed rivers

地下水供给河流中的磷动态

基本信息

批准号：
NE/G001707/1
负责人：
Ann Louise Heathwaite
金额：
$ 73.83万
依托单位：
Lancaster University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2008
资助国家：
英国
起止时间：
2008 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FG001707%2F1
关键词：
Phosphorus dynamics groundwater fed rivers

项目摘要

Reducing diffuse nutrient pollution is a prime focus of measures to improve the environmental status of UK rivers. In groundwater-fed rivers, processes operating in the hyporheic zone (HZ) and its interchange with surface waters (SW) are key drivers of the ecological health of the river. The HZ is the subsurface region beneath, or adjacent to, a SW body where mixing occurs with groundwater (GW). This zone is hydrologically, geochemically and microbiologically complex. Large redox-driven concentration gradients exist across the sediment-water interface. The resulting potential for complete consumption of dissolved oxygen in hyporheic flowpaths 10-100 cm into the streambed creates areas where anaerobic microorganisms dominate microbial activity, which in turn control the bioavailability of redox-sensitive elements such as nitrogen (N) and, indirectly, phosphorus (P). The retention/release of P through interaction between HZ flows and in-river (SW) processes may be particularly important because elevated P concentrations have been linked to increased rates of plant growth, changes in species composition and proliferation of planktonic and epiphytic and epibenthic algae in rivers. Such rivers often fail to meet the standards of the EU Water Framework Directive necessitating the introduction of expensive mitigation measures. These measures can only succeed if we understand the processes controlling the ecological health of the river. This project seeks to unravel these controls in relation to P dynamics in groundwater-fed rivers.The focus in on understanding of the temporal variation in nutrient processes in groundwater-fed rivers.

减少弥漫性营养污染是改善英国河流环境状况措施的主要焦点。在地下水河流中，在潜流带（HZ）运行的过程及其与地表水（SW）的交换是河流生态健康的关键驱动因素。HZ是在SW体之下或附近与地下水混合的地下区域（GW）。该带具有水文、地球化学和微生物的复合性。在沉积物-水界面上存在较大的氧化还原驱动浓度梯度。在10-100厘米深的低渗流道中，溶解氧完全消耗的可能性产生了厌氧微生物主导微生物活动的区域，这反过来又控制了氧化还原敏感元素(如氮（N)和间接的磷(P)）的生物利用度。由于磷浓度的升高与植物生长速度的加快、物种组成的变化以及河流中浮游、附生和底栖藻类的增殖有关，因此，通过HZ流和河内（SW）过程之间的相互作用，磷的保留/释放可能特别重要。这些河流往往达不到欧盟《水框架指令》的标准，因此需要采取昂贵的缓解措施。只有了解控制河流生态健康的过程，这些措施才能成功。该项目旨在揭示这些控制与地下水河流中的P动力学有关。重点是了解地下水河流中养分过程的时间变化。