Vertical Hyporheic Exchange and Nitrogen Transport and Transformation in Prairie Meandering Rivers
-
摘要: 潜流带是地表水与地下水之间发生水分和物质交换的关键区域，研究河流潜流带氮素转化对于改善河流水质，维持水生态系统稳定具有重要意义.为探究半干旱区草原曲流河潜流带内的氮素迁移转化过程，以锡林河弯曲河段为研究对象，结合水动力学和水化学法，分析了潜流带内的垂向潜流交换模式及氮素转化特征.结果表明：非降雨时期垂向潜流交换以微弱的上升流为主，平均水力梯度为-0.023.降雨和上游来水可能导致交换方向逆转，出现下降流，平均水力梯度为0.086.垂向潜流交换速率随深度增加而递减，河床表面以下20、50和100 cm处的平均交换速率分别为0.102、0.041和0.017 m·d-1，100 cm是垂向交换的下边界.潜流带中可能存在氨化、硝化、反硝化及异化还原反应，50 cm是热点反应深度，出现生物地球化学梯度的逆转.草原曲流河的垂向潜流带是NO3-的汇，且对NO3-的去除作用存在空间差异，深层沉积物的去除作用强于浅层.上升流和下降流条件下的NO3-平均去除率分别为34%和28%.曲流河段顶点处相对于入流及出流处，其垂向交换较弱，而氮素浓度较低，可能是曲流驱动下生物地球化学反应发生的热点位置.Abstract: The hyporheic zone is a critical interface between surface water and groundwater where water and materials exchange actively. The study of nitrogen transport and transformation in the hyporheic zone of rivers is of great significance for improving river water quality and maintaining the stability of water ecosystems. To investigate the nitrogen transport and transformation processes in the hyporheic zone of prairie meandering rivers in the semi-arid region, a meandering reach of the Xilin River was taken as the research object, and the vertical hyporheic exchange patterns and nitrogen transformation characteristics in the hyporheic zone were analyzed by combining the hydrodynamic and hydrochemical methods. The results show that the vertical hyporheic exchange is dominated by a weak upwelling flow with an average hydraulic gradient of -0.023 during the non-rainfall period. Rainfall and upland water can lead to a reversal of the exchange direction and an appearance of downwelling flow with an average hydraulic gradient of 0.086. The vertical hyporheic exchange rate decreases with depth, with the average exchange rate at 20, 50 and 100 cm below the surface of river bed is 0.102, 0.041 and 0.017 m·d-1, respectively, the depth of 100 cm is the lower boundary of vertical exchange. Ammonification, nitrification, denitrification and dissimilatory reduction reactions are likely to occur in the hyporheic zone, with the depth of 50 cm being the hot spot where the reversal of biogeochemical gradients occurs. The vertical hyporheiczone of prairie meandering rivers is a sink for nitrate. The removal effect on nitrate indicates spatial differences with stronger removal rate in deep sediments than in shallow ones. The average removal rate of nitrate were 34% and 28% under upwelling and downwelling conditions, respectively.Compared with the inflow and outflow points, the vertical exchange at the apex of the meandering reach is relatively weak, and the nitrogen concentration is low. The apex may be the hot spot of biogeochemical reactions in the hyporheic zones driven by meanders.
-
Key words:
- meandering river /
- hyporheic exchange /
- nitrogen transformation /
- nitrogen sink /
- riverbed /
- groundwater /
- hydrogeology
-
图 1 研究区概况（a）及监测井布设（b）
Fig. 1. Overview of the study area (a) and the layout of monitoring wells (b)
图 2 监测期内河水流量（a）及垂向水力梯度随时间的变化(b~f)
Fig. 2. Changes of surface water discharge (a) and vertical hydraulic gradient during monitoring periods (b-f)
图 3 水化学指标浓度在河水及潜流带内的垂向分布
Fig. 3. Vertical distribution of concentrations of hydrochemistry indicators within the river and hyporheic zone
图 4 上升流和下降流条件下硝酸盐的产生和消耗
Fig. 4. Nitrate production and consumption under upwelling and downwelling conditions
图 5 曲流河段不同点位的垂向水力梯度及氮素浓度的垂向分布
Fig. 5. Vertical distributions of hydraulic gradients and nitrogen concentrations at different positions in the meandering reach
图 6 锡林河垂向潜流交换及其氮素迁移转化的概念示意图
Fig. 6. Conceptual schematic diagram of vertical hyporheic exchange and nitrogen transport and transformation in the Xilin River
表 1 水化学参数在河水及潜流带中不同深度孔隙水中的平均值及标准偏差
Table 1. Mean concentrations and standard deviations of hydrochemical parameters in river water and in pore water at different depths in the hyporheic zone
水化学指标 T
(℃)EC
(µs·cm-1)SAL Cl-
(mg·L-1)DON
(mg·L-1)NH4+
(mg·L-1)NO3-
(mg·L-1)NO2-
(mg·L-1)DO
(mg·L-1)DOC
(mg·L-1)pH 河水 21.8±2.71 341.71±35.68 0.10±0.00 7.61±0.74 3.29±2.22 1.95±1.87 3.57±2.05 0.42±0.43 7.74±0.36 19.43±7.47 8.149±0.24 孔隙水 20 cm 19.37±2.70 396.00±32.15 0.10±0.00 13.24±3.95 2.77±1.18 1.52±1.14 3.85±2.32 0.50±0.45 3.24±1.59 18.06±4.83 7.629±0.42 50 cm 18.08±4.00 408.29±36.44 0.10±0.02 12.35±3.36 3.03±2.29 1.25±1.11 3.97±2.49 0.35±0.30 0.96±0.79 18.75±7.87 7.701±0.10 100 cm 19.13±3.90 367.00±14.40 0.10±0.00 9.42±0.96 2.79±1.75 1.32±0.88 3.06±2.34 0.31±0.22 0.94±0.62 13.64±7.72 7.697±0.15 注：表中所列数值为5组监测管，7次分批取样所获得的共112个样品的实测浓度的平均值及标准偏差. 
下载: 导出CSV
-
Boano, F., Demaria, A., Revelli, R., et al., 2010. Biogeochemical Zonation Due to Intrameander Hyporheic Flow. Water Resources Research, 46(2): 1-13. https://doi.org/10.1029/2008wr007583 Briggs, M. A., Lautz, L. K., Hare, D. K., 2014. Residence Time Control on Hot Moments of Net Nitrate Production and Uptake in the Hyporheic Zone. Hydrological Processes, 28(11): 3741-3751. https://doi.org/10.1002/hyp.9921 Byrne, P., Zhang, H., Ullah, S., et al., 2015. Diffusive Equilibrium in Thin Films Provides Evidence of Suppression of Hyporheic Exchange and Large-Scale Nitrate Transformation in a Groundwater-Fed River. Hydrological Processes, 29(6): 1385-1396. https://doi.org/10.1002/hyp.10269 Cardenas, M. B., 2008. The Effect of River Bend Morphology on Flow and Timescales of Surface Water-Groundwater Exchange across Pointbars. Journal of Hydrology, 362(1-2): 134-141. https://doi.org/10.1016/j.jhydrol.2008.08.018 Du, Y., Ma, T., Deng, Y. M., et al., 2017. Hydro-Biogeochemistry of Hyporheic Zone: Principles, Methods and Ecological Significance. Earth Science, 42(5): 661-673 (in Chinese with English abstract). Dudley-Southern, M., Binley, A., 2015. Temporal Responses of Groundwater-Surface Water Exchange to Successive Storm Events. Water Resources Research, 51(2): 1112-1126. https://doi.org/10.1002/2014wr016623 Dwivedi, D., Arora, B., Steefel, C. I., et al., 2018. Hot Spots and Hot Moments of Nitrogen in a Riparian Corridor. Water Resources Research, 54(1): 205-222. https://doi.org/10.1002/2017wr022346 Gomez-Velez, J. D., Wilson, J. L., Cardenas, M. B., et al., 2017. Flow and Residence Times of Dynamic River Bank Storage and Sinuosity-Driven Hyporheic Exchange. Water Resources Research, 53(10): 8572-8595. https://doi.org/10.1002/2017wr021362 Harvey, J. W., Böhlke, J. K., Voytek, M. A., et al., 2013. Hyporheic Zone Denitrification: Controls on Effective Reaction Depth and Contribution to Whole-Stream Mass Balance. Water Resources Research, 49(10): 6298-6316. https://doi.org/10.1002/wrcr.20492 Heathwaite, A. L., Heppell, C., Binley, A., et al., 2021. Spatial and Temporal Dynamics of Nitrogen Exchange in an Upwelling Reach of a Groundwater‐Fed River and Potential Response to Perturbations Changing Rainfall Patterns Under UK Climate Change Scenarios. Hydrological Processes, 35(4): e14135. https://doi.org//10.1002/hyp.14135 Heppell, C., Louise Heathwaite, A., Binley, A., et al., 2014. Interpreting Spatial Patterns in Redox and Coupled Water-Nitrogen Fluxes in the Streambed of a Gaining River Reach. Biogeochemistry, 117(2-3): 491-509. https://doi.org/10.1007/s10533-013-9895-4 Krause, S., Tecklenburg, C., Munz, M., et al., 2013. Streambed Nitrogen Cycling beyond the Hyporheic Zone: Flow Controls on Horizontal Patterns and Depth Distribution of Nitrate and Dissolved Oxygen in the Upwelling Groundwater of a Lowland River. Journal of Geophysical Research: Biogeosciences, 118(1): 54-67. https://doi.org/10.1029/2012jg002122 Kunz, J. V., Annable, M. D., Rao, S., et al., 2017. Hyporheic Passive Flux Meters Reveal Inverse Vertical Zonation and High Seasonality of Nitrogen Processing in an Anthropogenically Modified Stream (Holtemme, Germany). Water Resources Research, 53(12): 10155-10172. https://doi.org/10.1002/2017wr020709 Lansdown, K., Trimmer, M., Heppell, C. M., et al., 2012. Characterization of the Key Pathways of Dissimilatory Nitrate Reduction and Their Response to Complex Organic Substrates in Hyporheic Sediments. Limnology and Oceanography, 57(2): 387-400. https://doi.org/10.4319/lo.2012.57.2.0387 Li, A. G., Bernal, S., Kohler, B., et al., 2021. Residence Time in Hyporheic Bioactive Layers Explains Nitrate Uptake in Streams. Water Resources Research, 57(2): 1-16. https://doi.org/10.1029/2020wr027646 Li, G., Han, Z. W., Shen, C. H., et al., 2019. Distribution Characteristics and Causes of Nitrate in Waters of Typical Small Karst Catchment: A Case of the Houzhai River Catchment. Earth Science, 44(9): 2899-2908 (in Chinese with English abstract). Li, Y., Zhang, W. W., Yuan, J. H., et al., 2016. Research Advances in Flow Patterns and Nitrogen Transformation in Hyporheic Zones. Journal of Hohai University (Natural Sciences), 44(1): 1-7 (in Chinese with English abstract). doi: 10.3876/j.issn.1000-1980.2016.01.001 Li, Y. L., Sun, W., Yang, Z. R., 2017. Identification of Nitrate Sources and Transformation Processes in Midstream Areas: A Case in the Taizi River Basin. Environmental Science, 38(12): 5039-5046 (in Chinese with English abstract). Liu, Y. Y., Liu, C. X., Nelson, W. C., et al., 2017. Effect of Water Chemistry and Hydrodynamics on Nitrogen Transformation Activity and Microbial Community Functional Potential in Hyporheic Zone Sediment Columns. Environmental Science & Technology, 51(9): 4877-4886. https://doi.org/10.1021/acs.est.6b05018 Liu, S. N., Chui, T. F. M., 2018. Impacts of Different Rainfall Patterns on Hyporheic Zone under Transient Conditions. Journal of Hydrology, 561: 598-608. https://doi.org/10.1016/j.jhydrol.2018.04.019 Ma, P., Li, X. Y., Wang, H. X., et al., 2014. Denitrification and Its Role in Cycling and Removal of Nitrogen in River. Journal of Agro-Environment Science, 33(4): 623-633 (in Chinese with English abstract). Naranjo, R. C., Niswonger, R. G., Davis, C. J., 2015. Mixing Effects on Nitrogen and Oxygen Concentrations and the Relationship to Mean Residence Time in a Hyporheic Zone of a Riffle-Pool Sequence. Water Resources Research, 51(9): 7202-7217. https://doi.org/10.1002/2014wr016593 Ping, X., Xian, Y., Jin, M. G., 2018. Influence of Bioclogging on Nitrogen Cycling in a Hyporheic Zone with an Undulate River-Bed. Earth Science, 43(S1): 171-180 (in Chinese with English abstract). Ren, M. M., Huang, F., Hu, X. N., et al., 2020. Characteristics and Sources of Dissolved Inorganic Carbon and Nitrate in Lijiang River Basin. Earth Science, 45(5)1830-1843(in Chinese with English abstract). Shuai, P., Cardenas, M. B., Knappett, P. S. K., et al., 2017. Denitrification in the Banks of Fluctuating Rivers: The Effects of River Stage Amplitude, Sediment Hydraulic Conductivity and Dispersivity, and Ambient Groundwater Flow. Water Resources Research, 53(9): 7951-7967. https://doi.org/10.1002/2017wr020610 Song, J. X., Zhang, G. T., Wang, W. Z., et al., 2017. Variability in the Vertical Hyporheic Water Exchange Affected by Hydraulic Conductivity and River Morphology at a Natural Confluent Meander Bend. Hydrological Processes, 31(19): 3407-3420. https://doi.org/10.1002/hyp.11265 Su, X. S., Shi, Y. K., Dong, W. H., et al., 2019. Review on Biogeochemical Characteristics of Hyporheic Zone. Journal of Earth Sciences and Environment, 41(3): 337-351 (in Chinese with English abstract). Wu, G. D., Zhang, X., Lu, C. P., 2019. Spatial-Temporal Variability in Hyporheic Zone and Hyporheic Exchange. Yangtze River, 50(10): 100-107 (in Chinese with English abstract). doi: 10.11988/ckyyb.20190903 Xia, X. H., Liu, T., Yang, Z., et al., 2013. Dissolved Organic Nitrogen Transformation in River Water: Effects of Suspended Sediment and Organic Nitrogen Concentration. Journal of Hydrology, 484: 96-104. https://doi.org/10.1016/j.jhydrol.2013.01.012 Xu, H. S., Zhao, T. Q., Meng, H. Q., et al., 2011. Relationship between Groundwater Quality Index of Physics and Chemistry in Riparian Zone and Water Quality in River. Environmental Science, 32(3): 632-640 (in Chinese with English abstract). Yan, Y. Q., 2018. Nitrogen Migration and Transformation Law and Its Key Process Influencing Factors in Jinghe Subsurface Flow Zone (Dissertation). Northwest A & F University, Yangling(in Chinese with English abstract). Yan, Y. N., Ma, T., Zhang, J. W., et al., 2017. Experiment on Migration and Transformation of Nitrate under Interaction of Groundwater and Surface Water. Earth Science, 42(5): 783-792 (in Chinese with English abstract). Yan, Z. L., Liu, R. Y., Yan, Z. H., et al., 2021. Study on the Variation of Ammonia Nitrogen in Seawater Pond Aquaculture Water. Rural Scientific Experiment, (11): 123-125(in Chinese with English abstract). Yang, L., 2018. Analysis of Hydrochemical and Isotopic Characteristics of Different Water Bodies in Xilin River Basin (Dissertation). Inner Mongolia Agricultural University, Hohhot (in Chinese with English abstract). Zhang, C. X., 2016. Applicatin of Slug Testing Based on Hvorslev Mode. Railway Investigation and Surveying, 42(2): 16-20(in Chinese with English abstract). Zhang, H. T., Zhang, D. L., Hong, M., et al., 2014. Experimental Study on Effect of Carbon Sources on Nitrogen Migration in Hyporheic Zone. Yangtze River, 45(14): 22-26 (in Chinese with English abstract). Zhang, L., Zhu, Z. Y., Wang, H. M., et al., 2020. Analysis of Hydrological Drought Evolution Characteristics and Influencing Factors in Xilin River Basin. Journal of Soil and Water Conservation, 34(4): 178-184, 192 (in Chinese with English abstract). Zhou, Y. J., Liu, T. X., Duan, L. M., et al., 2020. Estimation of Evapotranspiration and Its Spatiotemporal Characteristics in the Upper Reaches of the Xilin River Basin. Arid Zone Research, 37(4): 974-984 (in Chinese with English abstract). 杜尧, 马腾, 邓娅敏, 等, 2017. 潜流带水文-生物地球化学: 原理、方法及其生态意义. 地球科学, 42(5): 661-673. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX201705001.htm 李耕, 韩志伟, 申春华, 等, 2019. 典型岩溶小流域水体中硝酸盐分布特征及成因: 以普定后寨河流域为例. 地球科学, 44(9): 2899-2908. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX201909008.htm 李艳利, 孙伟, 杨梓睿, 2017. 太子河流域中游地区河流硝酸盐来源及迁移转化过程. 环境科学, 38(12): 5039-5046. https://www.cnki.com.cn/Article/CJFDTOTAL-HJKZ201712018.htm 李勇, 张维维, 袁佳慧, 等, 2016. 潜流带水流特性及氮素运移转化研究进展. 河海大学学报(自然科学版), 44(1): 1-7. https://www.cnki.com.cn/Article/CJFDTOTAL-HHDX201601001.htm 马培, 李新艳, 王华新, 等, 2014. 河流反硝化过程及其在河流氮循环与氮去除中的作用. 农业环境科学学报, 33(4): 623-633. https://www.cnki.com.cn/Article/CJFDTOTAL-NHBH201404003.htm 平雪, 鲜阳, 靳孟贵, 2018. 河床起伏条件下生物堵塞对潜流带氮素迁移转化的影响. 地球科学, 43(增刊1): 171-180. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX2018S1017.htm 任梦梦, 黄芬, 胡晓农, 等, 2020. 漓江流域碳氮同位素组成特征及其来源初探. 地球科学, 45(5): 1830-1843. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX202005025.htm 苏小四, 师亚坤, 董维红, 等, 2019. 潜流带生物地球化学特征研究进展. 地球科学与环境学报, 41(3): 337-351. https://www.cnki.com.cn/Article/CJFDTOTAL-XAGX201903009.htm 吴光东, 张潇, 鲁程鹏, 2019. 河流潜流带和潜流交换时空变异特征研究综述. 人民长江, 50(10): 100-107. https://www.cnki.com.cn/Article/CJFDTOTAL-RIVE201910018.htm 徐华山, 赵同谦, 孟红旗, 等, 2011. 河岸带地下水理化指标变化及与洪水的响应关系研究. 环境科学, 32(3): 632-640. https://www.cnki.com.cn/Article/CJFDTOTAL-HJKZ201103004.htm 闫雅妮, 马腾, 张俊文, 等, 2017. 地下水与地表水相互作用下硝态氮的迁移转化实验. 地球科学, 42(5): 783-792. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX201705013.htm 闫玉琴, 2018. 泾河潜流带氮迁移转化规律及其关键过程影响因素(硕士学位论文). 杨凌: 西北农林科技大学. 严正凛, 刘瑞义, 严志洪, 等, 2021. 海水池塘养殖水体中氨氮的变化规律研究. 农村科学实验, (11): 123-125. https://www.cnki.com.cn/Article/CJFDTOTAL-HBYU201008005.htm 杨璐, 2018. 锡林河流域不同水体的水化学和同位素特征分析(硕士学位论文). 呼和浩特: 内蒙古农业大学. 张昌新, 2016. 基于Hvorslev模型的微水试验应用. 铁道勘察, 42(2): 16-20. https://www.cnki.com.cn/Article/CJFDTOTAL-TLHC201602007.htm 张海涛, 张迪龙, 洪梅, 等, 2014. 碳源对潜流带中氮素迁移转化影响的实验研究. 人民长江, 45(14): 22-26. https://www.cnki.com.cn/Article/CJFDTOTAL-RIVE201414008.htm 张璐, 朱仲元, 王慧敏, 等, 2020. 锡林河流域水文干旱演变特征及影响因素分析. 水土保持学报, 34(4): 178-184, 192. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQS202004027.htm 周亚军, 刘廷玺, 段利民, 等, 2020. 锡林河流域上游蒸散发估算及其时空特征. 干旱区研究, 37(4): 974-984. https://www.cnki.com.cn/Article/CJFDTOTAL-GHQJ202004018.htm -
点击查看大图
图(6) / 表(1)
计量
- 文章访问数: 371
- HTML全文浏览量: 398
- PDF下载量: 35
- 被引次数: 0
