Smart tracers and distributed sensor networks for quantifying the metabolic activity in streambed reactivity hotspots

智能示踪剂和分布式传感器网络，用于量化河床反应热点的代谢活动

• 批准号: NE/I016120/1
• 负责人: Stefan Krause
• 金额: $ 6.67万
• 依托单位: Keele University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FI016120%2F1
• 关键词: Smart; tracers; distributed; sensor; networks

There are major concerns amongst regulators and river managers that at locations where rivers are well connected to the surrounding aquifer, the up-welling of contaminated groundwater can represent a severe risk to the surface water quality and the ecological conditions in the river and cause significant economical damage. For assessing the environmental risks associated with the discharge of contaminated groundwater into surface waters, regulators and river managers urgently require detailed information of the natural attenuation potential of groundwater aquifers and aquifer-river interfaces. While the natural attenuation potential in groundwater aquifers is often limited due to a lack organic carbon and microbial activity, the mixing of groundwater and surface water in streambeds can provide higher concentrations of organic carbon and thus, stimulate enhanced metabolic activity and increase natural attenuation. Initial research of the investigator indicated that aquifer-river interfaces of lowland rivers may contain hotspots of metabolic activity in anoxic, high carbon pockets underneath peat and clay structures in the streambed. This project is designed to identify such locations and quantify the metabolic activity of these streambed reactivity hotspots in order to provide regulators and river managers with the knowledge urgently required for assessing the natural attenuation potential of aquifer-river interfaces. This study therefore applies fibre-optic Distributed Temperature Sensing (FO-DTS) to monitor streambed temperature patterns in high detail (0.01 C accuracy, 2 m spatial resolution) along a fibre-optic cable deployed in the streambed. It will identify locations with intensive groundwater up-welling (cold spots) against areas with inhibited groundwater up-welling (warm spots) during summer months when groundwater and surface water temperatures differ by 6 - 10 C. Streambed multi-level mini-piezometers will be installed in identified warm spots, where the delayed up-welling of cold groundwater is expected to indicate potential reactivity hotspots with increased metabolic activity underneath streambed peat structures. For comparison, piezometers will also be installed in identified cold spots caused by intensive groundwater up-welling, indicating high groundwater-surface water connectivity with low residence times and potentially low natural metabolic activity. A smart tracer, combining the reactive (resazurine) and non-reactive (NaCl) compounds will be injected at the bottom (150 cm depth) of the piezometers and breakthrough curves will be analysed at 15 cm intervals along the multi-level piezometers. NaCl breakthrough curves will be used to calculate groundwater up-welling rates and residence times whereas the reduction of resazurine to the strongly fluorescent substance resorufin will be used in a reactive decay simulation to indicate the microbial metabolic activity at the respective depths. Metabolic activity and residence times will be compared to nitrate concentrations, redox-potential, dissolved oxygen and organic carbon content at the piezometers locations to proof that metabolic activity hotspots increase the natural attenuation potential. The result of this project will provide regulators and river basin managers with the urgently required understanding of the natural attenuation potential of streambed reactivity hotspots of enhanced microbial activity. The knowledge provided by this project is of great importance for a range of related scientific disciplines as well as regulators and river basin managers. Thermal conditions are an integral part of the ecosystem health of hydrological systems. The improved understanding of heat flow in streambeds will directly benefit aquatic ecologists and eco-hydrologists while advanced knowledge on metabolic activity hotspots will greatly benefit future research of multi-contaminant reactive transport and biogeochemical cycling at aquifer-river interfaces.

监管机构和河流经理之间存在着主要的担忧，即在河流与周围含水层良好联系的地点，受污染的地下水的上波可能代表地表水质和河流生态状况的严重风险，并造成严重的经济损害。为了评估与将污染的地下水排入地表水域相关的环境风险，监管机构和河流管理人员急需详细的信息，以了解地下水含水层和含水层河流式界面的自然衰减潜力。尽管由于缺乏有机碳和微生物活性，地下水含水层中的自然衰减潜力通常受到限制，但河床中地下水和地表水的混合可以提供更高浓度的有机碳，从而刺激增强的代谢活性并增加自然衰减。研究人员的初步研究表明，低地河流的含水层摩托车界面可能包含在泥炭台下的泥炭和粘土结构下的缺氧，高碳袋中代谢活性的热点。该项目旨在识别此类位置并量化这些流床反应性热点的代谢活性，以便为调节器和河流经理提供迫切需要评估含水层河流接口的自然衰减潜力所需的知识。因此，这项研究沿着纤维电缆部署在流床中的纤维电缆上，应用了纤维形成的分布温度传感（FO-DTS），以高度详细（0.01 c精度，2 m空间分辨率）监测流床温度模式。 It will identify locations with intensive groundwater up-welling (cold spots) against areas with inhibited groundwater up-welling (warm spots) during summer months when groundwater and surface water temperatures differ by 6 - 10 C. Streambed multi-level mini-piezometers will be installed in identified warm spots, where the delayed up-welling of cold groundwater is expected to indicate potential reactivity hotspots with increased metabolic activity underneath streambed peat structures.为了进行比较，在强烈的地下水上沃特引起的鉴定的冷点还将安装压力计，表明地下水面水连通性高，停留时间较低，自然代谢活性可能低。将在压电仪的底部（150 cm深度）注入一个智能示踪剂，将反应性（蒸发）和非反应性（NaCl）化合物组合在一起，并将在沿多层打压缩机沿15 cm的间隔分析。 NaCl突破性曲线将用于计算地下水上下沃特速率和停留时间，而将炼油碱降低到强荧光物质中，将用于反应性衰减模拟中，以指示各自深度的微生物代谢活性。将代谢活性和停留时间与硝酸盐浓度，氧化还原电势，溶解的氧气和有机碳含量在压电仪位置进行比较，以证明代谢活性热点会增加自然衰减潜力。该项目的结果将为监管机构和河流经理提供迫切需要了解增强微生物活性的流床反应性热点的自然衰减潜力。对于一系列相关的科学学科以及监管机构和河流经理，该项目提供的知识非常重要。热条件是水文系统生态系统健康不可或缺的一部分。对流床的热流的提高理解将直接使水生生态学家和生态流行病学家受益，而对代谢活动热点的先进知识将极大地使对含水层摩托车界面的多抗药性反应性运输和生物地球化学循环的未来研究有利。

项目成果

The method controls the story - Sampling method impacts on the detection of pore-water nitrogen concentrations in streambeds.

该方法控制了故事 - 采样方法对河床孔隙水氮浓度检测的影响。

• DOI: 10.1016/j.scitotenv.2019.136075
• 发表时间: 2020
• 期刊: The Science of the total environment
• 作者: Comer-Warner S

Is the Hyporheic Zone Relevant beyond the Scientific Community?

• DOI: 10.3390/w11112230
• 发表时间: 2019-11-01
• 期刊: WATER
• 影响因子: 3.4
• 作者: Lewandowski, Joerg;Arnon, Shai;Wu, Liwen
• 通讯作者: Wu, Liwen

Instream wood increases riverbed temperature variability in a lowland sandy stream

河内木材增加了低地沙质河流的河床温度变化

• DOI: 10.1002/rra.3698
• 发表时间: 2020
• 期刊: River Research and Applications
• 影响因子: 2.2
• 作者: Klaar M

Identification of floodplain and riverbed sediment heterogeneity in a meandering UK lowland stream by ground penetrating radar

利用探地雷达识别英国蜿蜒低地溪流中的漫滩和河床沉积物异质性

• DOI: 10.1016/j.jappgeo.2019.103863
• 发表时间: 2019
• 期刊: Journal of Applied Geophysics
• 影响因子: 2
• 作者: Dara R