河流潜流带生物扰动的生态-水文过程响应机理

Surface water and groundwater are two interconnected components of one single resource and impacts on either of these components in the hyporheic zone, which will inevitably affect the quantity or quality of the other. Determination of invertebrate communities and their effects on ecological and hydrological processes of hyporheic zone is of great importance in integrated management of groundwater and surface water bodies and in maintenance of ecosystem health of a river catchment. As a case study of the Weihe River, stream water and groundwater are inherently connected and water quality is strongly interacted. Therefore, the influence mechanism of invertebrate bioturbations on ecological and hydrological processes in the hyporheic zone of the Weihe River is studied. Firstly, the macroinvertebrate communities and their assemblage change with place and seasons in the hyporheic zone are determined. Then, the effect of typical invertebrate bioturbations on ecological and hydrological processes are estimated and illustrated on the basis of integrated application of trace methods including thermal tracer, fluorescent luminophores tracer, coloured particles tracer and Bromide tracer, as well as techniques including deoxyribonucleic acid (DNA) extraction, polymerase chain reaction (PCR) amplification and Image-Pro Plus, respectively. Secondly, the corresponding change and interaction of hyporheic ecological and hydrological processes and their dynamic mechanism caused by invertebrate bioturbations are analyzed and discussed. Finally, the influence mechanism of invertebrate bioturbtions on ecological and hydrological processes in the hyporheic zone is suggested. This study will be helpful for a deeper understanding of the functions of invertebrate bioturbation and their dynamic mechanism on the development of ecological and hydrological processes in the hyporheic zone. It provides a theoretical approach for determination of the role of organisms in hyporheic processes, and even a scientific reference for controlling water pollution of both surface water and groundwater, and improving ecosystem health conditions of both waterway and catchment of a river basin.

深入研究河流潜流生物群落结构及其对生态-水文过程的作用机理在维持流域生态健康中起着十分重要的作用。本课题以河水与地下水相互作用明显的渭河作为研究区域，以大型无脊椎动物为研究对象，通过调查研究，确定渭河流域潜流带大型无脊椎动物群落结构的时空格局和生态学特征，在此基础上，通过原位试验测试分析与移位实验模拟研究，采用光、热、有色颗粒及溶质等多种示踪剂法，结合水力渗流试验、DNA提取、PCR扩增与图像分析等多种技术手段，进行生物扰动对生态-水文过程要素影响的科学测定，揭示潜流带生物扰动对生态-水文过程的影响效应，分析潜流带生物扰动作用下生态-水文过程演变规律及其驱动与互馈机制，试图解析潜流带生物扰动的生态-水文过程响应机理。本课题的研究，有利于深化潜流带生物扰动对生态-水文过程影响效应及其作用机理的的科学认识，将为河流-地下水系统的科学管理与持续利用，以及河流健康维护与修复提供理论依据。

深入研究河流潜流生物群落结构及其对生态-水文过程的作用机理在维持流域生态健康中起着十分重要的作用。本项目以河水与地下水相互作用明显的渭河作为研究区域，以大型无脊椎动物为研究对象，通过调查研究，发现渭河流域大型无脊椎动物168种，隶属于3门，7纲，18目，59科，主要包括软体动物、环节动物和节肢动物。其中，节肢动物共120种，物种数量最多，占物种总数的88.9%，环节动物次之，软体动物最少。平水期平均生物密度显著大于丰水期；大型无脊椎动物的生物密度在0-20厘米沉积层体现出北洛河>泾河>渭河，溶解氧、pH、水深和流速等是影响大型无脊椎动物群落的最主要因素，从而明确了潜流带生物群落结构的时空格局及其对环境响应机理。同时，基于温度示踪法，对渭河流域潜流带水交换做了测试与分析，研究发现：河流形态、沉积物异质性、河岸植被等对潜流带水交换具有显著影响，进一步解析了潜流带水交换变化机理；并且结合室内模拟实验，分析了大型无脊椎动物种类和生物密度等指标与沉积物渗透性系数、潜流带交换量之间的相关性，发现无脊椎动物如颤蚓的生物扰动会对潜流带水交换造成显著影响，但这种影响也存在一定的临界值；通过生物扰动与重金属以及含氮污染物等的影响实验研究，得出颤蚓扰动对Cr、Cu等重金属量值变化具有显著影响效应，摇蚊幼虫对于沉积物中总氮释放有着明显促进作用等结论。结合生物扰动的生物和动力学机制，解译大型无脊椎动物扰动对潜流带水交换以及对污染物迁移转化的影响效应与作用机理。此外，进一步深入分析生物扰动-水文-水质与水生态相互作用，系统研究潜流带生物扰动对生态-水文过程变化的响应机理，揭示了潜流带生物扰动下水文-生态过程的响应机理。上述研究成果，有利于深化潜流带生物扰动对生态-水文过程影响效应及其作用机理的科学认识，为河流-地下水系统的科学管理与持续利用，河流健康维护与河流生态系统功能修复提供理论依据与技术支撑。