摘要
河流筑坝发电是目前最为显著的人为扰动河流事件,形成的水电水库阻断了河流连续体,改变了其中生源要素的生物地球化学循环过程,但相关的影响机制还不完全清楚。为此,本研究以乌江11座水电水库为研究对象,季节性调查了水库及相应河流的生源要素(CO_(2)、溶解态无机氮DIN、溶解态无机磷DIP和溶解态硅DSi)浓度及相关的理化因子,以了解河流水库化过程中生源要素浓度的变化过程及水动力条件的变化对其生物地球化学循环的影响机制。结果表明,河流区CO_(2)、DIN、DIP和DSi浓度均高于水库区,水库区内各理化因子间的关联度显著高于河流区。研究水库对各种生源要素的同化效率表现出显著的时空差异;其中对CO_(2)和DSi的同化效率最高,季度均值分别为50%和40%。库区中各生源要素的同化效率和分层强度均与水力负荷显著负相关,表明水电水库的水动力条件是调控其生物地球化学循环强度的关键因素;滞留时间较长和较深的水电水库有利于浮游植物同化生源要素和促进其在剖面上的季节性分层。研究将加深对筑坝河流元素生物地球化学循环过程的认识,有助于水电水库管理措施的制定。
Dam construction for hydropower generation represents one of the most prominent human-induced disturbances in rivers.The formation of hydropower reservoirs interrupts river continuity,altering the biogeochemical cycles of nutrient elements within.However,the exact mechanisms underlying these effects remain not entirely understood.To address this knowledge gap,this study focuses on 11 hydropower reservoirs along the Wujiang River.Seasonal surveys were conducted to assess the concentrations of nutrient elements,i.e.carbon dioxide(CO_(2)),dissolved inorganic nitrogen(DIN),dissolved inorganic phosphorus(DIP),and dissolved silicon(DSi)in both the reservoirs and corresponding river sections,alongside relevant physicochemical parameters.The aim was to comprehend the variation in nutrient concentrations during the river-reservoir transition and to elucidate the impact of changes in hydrodynamic conditions on their biogeochemical cycles.Results revealed that CO_(2),DIN,DIP,and DSi concentrations were higher in river sections compared to reservoir areas.Additionally,the correlation between various physicochemical parameters within reservoir areas was notably higher than in river sections.The assimilation efficiency of various nutrient elements exhibited significant spatiotemporal variations within the reservoirs.Specifically,the assimilation efficiency was highest for CO_(2) and DSi,with seasonal averages of 50%and 40%,respectively.The assimilation efficiency and stratification intensity of nutrient elements within reservoirs showed a significant negative correlation with hydraulic load.This indicates that the hydrodynamic conditions of hydropower reservoirs are key factors regulating their biogeochemical cycling intensity.Longer retention time and deeper hydropower reservoirs favor the assimilation of nutrient elements by phytoplankton,promoting seasonal stratification within the water column.This research enhances our understanding of the biogeochemical cycling processes of dammed rivers,and willfacilitate the formulatio
作者
岳馨睿
肖晶
李婉珠
王宝利
YUE Xinrui;XIAO Jing;LI Wanzhu;WANG Baoi(Institute of Surface-Earth Science System,School of Earth Science System,Tianjin University,Tianjin 300072,China)
出处
《地球与环境》
CAS
CSCD
北大核心
2024年第5期596-606,共11页
Earth and Environment
基金
国家自然科学基金重大项目(42293264)
国家科技基础资源调查计划(2021FY101000)。
关键词
生源要素
水电水库
水力负荷
生物地球化学循环
乌江
nutrients
hydroelectric reservoirs
hydraulic load
biogeochemical cycles
Wujiang River
