洪湖地下水排泄及其携带营养盐通量量化的方法学研究  

A methodological study on the quantification of lacustrine groundwater discharge and nutrient fluxes to Honghu Lake

作　　者：韩鹏 甘义群 杜尧 孙晓梁 徐睿 吴婧 HAN Peng;GAN Yiqun;DU Yao;SUN Xiaoliang;XU Rui;WU Jing(School of Environmental Studies,China University of Geosciences(Wuhan),Wuhan 430078,China;Seventh Geological Team of Hubei Geological Bureau,Yichang Hubei 443111,China)

机构地区：[1]中国地质大学(武汉)环境学院,武汉430078 [2]湖北省地质局第七地质大队,湖北宜昌443111

出　　处：《地质科技通报》2025年第1期285-297,共13页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金联合基金重点项目(U21A2026)。

摘　　要：地下水在湖泊水量与营养盐均衡中的重要性日益受到关注,地下水向湖泊排泄水量与营养盐的时空变异性是当前研究的热点与难点。洪湖是长江中游的大型淡水湖泊,具有重要的调蓄功能和生态功能,但地下水在洪湖水循环与营养盐循环中的作用尚未受到关注。以洪湖为研究对象,在完整水文年内开展了2次(3月和9月)样品采集,通过电导率、氢氧同位素、^(222)Rn,对洪湖地区湖泊地下水排泄(LGD)进行了多手段示踪,利用^(222)Rn质量平衡模型量化了不同期次的LGD速率及其携带氮磷的输入通量,并对量化结果进行了敏感性分析。结果显示:(1)^(222)Rn、电导率(EC)和氢氧同位素共同指示了湖泊地下水排泄的存在;(2)洪湖整体的湖泊地下水排泄速率在3月和9月分别为(33.32±18.78)mm/d和(10.97±6.76)mm/d,由于异常年份的极端干旱导致的洪湖区域地下水位的下降使得9月的地下水排泄速率小于3月。(3)地下水排泄对湖泊总氮的输入通量3月为(90.75±64.06)mg/(m^(2)·d),9月为(30.09±21.75)mg/(m^(2)·d),分别占洪湖外源输入的54.72%和12.70%;总磷输入通量3月为(6.85±4.76)mg/(m^(2)·d),9月为(3.51±2.48)mg/(m^(2)·d),分别占洪湖外源输入的52.49%和10.40%。(4)风速、湖水^(222)Rn活度和地下水^(222)Rn活度是量化结果的敏感参数。本研究为洪湖地下水排泄及其携带营养盐输入通量的量化提供了一种新的研究方法,为洪湖及长江中游区域的湖泊水资源管理与水生态保护提供了重要的理论基础,并对其他同类型湖泊与地下水相互作用研究提供了参考。[Objective]The importance of groundwater in maintaining the balance of water volume and nutrient salts in lakes has garnered increasing attention.Understanding the spatiotemporal variability of groundwater discharge and associated nutrient fluxes into lakes is currently a hot and difficult research topic.Honghu Lake,a large freshwater lake located in the middle reaches of the Yangtze River,plays a crucial role in regional regulatory and ecological functions.However,the contribution of groundwater to the water cycle and nutrient dynamics of Honghu Lake has not been adequately explored.[Methods]This study focuses on Honghu Lake,collecting samples during two periods(March and September)throughout a hydrological year.By utilizing multiple tracers including electrical conductivity(EC),hydrogen and oxygen isotopes,and ^(222)Rn,the lake bottom groundwater discharge.(LGD)in the Honghu Lake area was explored.A ^(222)Rn mass balance model was applied to quantify the LGD rate and the input fluxes of nitrogen and phosphorus carried by LGD during different periods.Additionally,a sensitivity analysis of the quantitative results was conducted.[Results]The results show that(1)the combined use of ^(222)Rn,EC,and hydrogen and oxygen isotopes confirms the presence of groundwater discharge from the lake bed;(2)the overall groundwater discharge rates at the bottom of Honghu Lake were(33.32±18.78)mm/d in March and(10.97±6.76)mm/d in September.Owing to the decrease in groundwater level in the Honghu Lake area resulting from extreme drought in abnormal years,the groundwater discharge rate in September was lower than that in March;(3)The nitrogen input carried by groundwater discharge to the lake was(90.75±64.06)mg/(m^(2)·d)in March and(30.09±21.75)mg/(m^(2)·d)in September,accounting for 54.72%and 12.70%of the external nitrogen input to Honghu Lake,respectively.The phosphorus input flux from groundwater was(6.85±4.76)mg/(m^(2)·d)in March and(3.51±2.48)mg/(m^(2)·d)in September,accounting for 52.49%and 10.40%of the external input

关 键 词：湖泊 地下水排泄 营养盐通量 ^(222)Rn 氮 磷 洪湖 

分 类 号：P641.11[天文地球—地质矿产勘探]