河流潜流带水交换作用对氮迁移转化过程的影响  

Study on the influence of water exchange in river hyporheic zone on nitrogen migration and transformation process

作　　者：彭闯 干牧凡 车景璐 张妍 时鹏 PENG Chuang;GAN Mufan;CHE Jinglu;ZHANG Yan;SHI Peng(College of Urban and Environmental Science,Northwest University,Xi′an 710127,China;State Key Laboratory of Eco-hydraulics in Northwest Arid Region,Xi′an,University of Technology,Xi′an 710048,China)

机构地区：[1]西北大学城市与环境学院,西安710127 [2]西安理工大学西北旱区生态水利国家重点实验室,西安710048

出　　处：《生态学报》2024年第23期10794-10806,共13页Acta Ecologica Sinica

基　　金：国家自然科学基金面上项目(42273056)。

摘　　要：氮在地球生物化学循环中扮演着重要角色,河流潜流带是河水与地下水相互作用及污染物迁移的关键通道,水交换作用是驱动潜流带中物质发生生物化学作用的重要动力,正确认识河流潜流带不同水交换作用对氮迁移转化过程的影响机制对维持河流生态系统健康和全球水安全至关重要。采集渭河潜流带原状沉积物,通过室内模拟实验,研究不同水交换作用模式下潜流带中氮的迁移转化过程。结果表明:由于河流潜流带中不同的水交换作用导致水流形态和溶解氧(DO)浓度的差异,进而影响氧化还原电位(Eh)和微生物群落结构等因素的不同,从而影响河流潜流带中氮素的迁移和转化过程。在地表水补给地下水过程中,NO_(3)^(-)-N和NO_(2)^(-)-N的含量沿着水分运移的方向增加,NH+4-N的含量则沿着水分运移的方向减少,在地下水补给地表水过程中也表现出相同趋势,这表明河流潜流带水交换作用过程中NO_(3)^(-)-N发生了迁移。反硝化作用和异化还原成铵作用(DNRA)是河流潜流带水交换作用下NO_(3)^(-)-N转化的主要途径,地下水补给地表水过程中主要微生物类型是变形菌门,反硝化作用强于地表水补给地下水过程;地表水补给地下水过程中主要微生物类型是厚壁菌门,DNRA作用更强烈。地表水补给地下水过程和地下水补给地表水过程中河流潜流带沉积物对NO_(3)^(-)-N的总截留率分别为97.7%和98.2%,其中,在地表水补给地下水模式下,0—15、15—30、30—45 cm和45—60 cm沉积层对NO_(3)^(-)-N的截留率分别为34.8%、24.5%、23.5%和14.9%,而在地下水补给地表水模式下,0—15、15—30、30—45 cm和45—60 cm沉积层对NO_(3)^(-)-N的截留率分别为21.6%、24.3%、25.0%和27.3%,两种模式呈现相反的变化趋势,但都在沉积物—水界面对NO_(3)^(-)-N的截留率最高。因此,河流潜流带水交换作用对氮迁移转化过程有显著影响,本研究对�The importance of nitrogen within the Earth′s biochemical cycle cannot be overstated.It is a vital component in numerous ecological processes,particularly crucial within river ecosystems.The hyporheic zone is the key channel for the interaction between river water and groundwater,and the migration of pollutants.There is frequent water exchange between river water and groundwater,driving the migration and transformation of substances as well as biochemical cycling in the hyporheic zone.The correct understand of the mechanism of the influence of different water exchanges on nitrogen migration and transformation processes is crucial to maintaining the health of river ecosystems and global water security.This study collected hyporheic sediments from the Weihe River Basin and conducted simulation experiments to investigate nitrogen migration and transformation processes within the hyporheic zone under various water exchange modes.The findings indicated that different water exchanges in the hyporheic zone of rivers led to differences in water flow morphology and dissolved oxygen(DO)concentration,which in turn affected factors such as Oxidation-reduction potential(Eh)and microbial community structure,thereby affecting the migration and transformation process of nitrogen in the hyporheic zone of rivers.During the process of surface water recharging groundwater,there was a noticeable increase in NO_(3)^(-)-N and NO_(2)^(-)-N content along the water migration path,while NH+4-N content decreased.Similarly,this trend persisted when groundwater replenished surface water,suggesting NO_(3)^(-)-N migration during water exchange in the river′s undercurrent zone.Denitrification and dissimilatory reduction to ammonium(DNRA)emerged as the primary pathways for NO_(3)^(-)-N conversion during this exchange in the underflow zone of rivers.Proteobacteria dominated during the process of groundwater recharge to surface water,favoring denitrification over surface water recharge.Conversely,Firmicutes prevailed during the process of groun

关 键 词：河流潜流带 水交换作用 氮迁移转化 微生物群落 

分 类 号：X143[环境科学与工程—环境科学]