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Jiang H, Liu W, Li Y, Zhang J, Xu Z. Multiple Isotopes Reveal a Hydrology Dominated Control on the Nitrogen Cycling in the Nujiang River Basin, the Last Undammed Large River Basin on the Tibetan Plateau. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:4610-4619. [PMID: 35294176 DOI: 10.1021/acs.est.1c07102] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The Tibetan Plateau is sensitive to climate change, but the feedbacks of nitrogen (N) cycling to climate conditions on this plateau are not well-understood, especially under varying degrees of anthropogenic disturbances. The Nujiang River Basin, the last undammed large river basin on the Tibetan Plateau, provides an opportunity to reveal the feedbacks at a broad river basin scale. The isotopic compositions revealed that the conservative mixing of multiple sources controlled the nitrate (NO3-) loadings during the low-flow season, while biological removal processes (assimilation and denitrification) occurred in the high-flow season. During the high-flow season, soil sources, sewage, and atmospheric precipitation contributed 76.3%, 15.6%, and 8.1% to the riverine NO3-. In the low-flow season, the contribution of soil sources decreased while that of sewage increased. The relationship between d-excess and δ15N-NO3- suggests that the hydrological conditions largely controlled the N cycling dynamics in the basin, causing the high spatiotemporal heterogeneity of the riverine NO3- sources and transformation mechanisms. During the high-flow season, the precipitation and evaporation patterns controlled the in-soil processes and soil leaching. In contrast, in-stream nitrification became more evident during the low-flow season, which was related to the long water residence time. This study illustrates hydrology dominated control on N cycling over a large basin scale, which has implications for understanding the N cycling dynamics in the Tibetan Plateau.
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Affiliation(s)
- Hao Jiang
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenjing Liu
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuanchuan Li
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiangyi Zhang
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhifang Xu
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Clifford HM, Potocki M, Koch I, Sherpa T, Handley M, Korotkikh E, Introne D, Kaspari S, Miner K, Matthews T, Perry B, Guy H, Gajurel A, Singh PK, Elvin S, Elmore AC, Tait A, Mayewski PA. A case study using 2019 pre-monsoon snow and stream chemistry in the Khumbu region, Nepal. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 789:148006. [PMID: 34082206 DOI: 10.1016/j.scitotenv.2021.148006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 05/11/2021] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
This case study provides a framework for future monitoring and evidence for human source pollution in the Khumbu region, Nepal. We analyzed the chemical composition (major ions, major/trace elements, black carbon, and stable water isotopes) of pre-monsoon stream water (4300-5250 m) and snow (5200-6665 m) samples collected from Mt. Everest, Mt. Lobuche, and the Imja Valley during the 2019 pre-monsoon season, in addition to a shallow ice core recovered from the Khumbu Glacier (5300 m). In agreement with previous work, pre-monsoon aerosol deposition is dominated by dust originating from western sources and less frequently by transport from southerly air mass sources as demonstrated by evidence of one of the strongest recorded pre-monsoon events emanating from the Bay of Bengal, Cyclone Fani. Elevated concentrations of human-sourced metals (e.g., Pb, Bi, As) are found in surface snow and stream chemistry collected in the Khumbu region. As the most comprehensive case study of environmental chemistry in the Khumbu region, this research offers sufficient evidence for increased monitoring in this watershed and surrounding areas.
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Affiliation(s)
- Heather M Clifford
- Climate Change Institute, University of Maine, ME, USA; School of Earth and Climate Sciences, University of Maine, ME, USA.
| | - Mariusz Potocki
- Climate Change Institute, University of Maine, ME, USA; School of Earth and Climate Sciences, University of Maine, ME, USA
| | - Inka Koch
- International Centre for Integrated Mountain Development, Lalitpur, Nepal; Department of Geosciences, University of Tübingen, Tübingen, Germany
| | - Tenzing Sherpa
- International Centre for Integrated Mountain Development, Lalitpur, Nepal
| | - Mike Handley
- Climate Change Institute, University of Maine, ME, USA
| | | | | | - Susan Kaspari
- Department of Geological Sciences, Central Washington University, WA, USA
| | | | - Tom Matthews
- Department of Geography and Environment, Loughborough University, Loughborough, UK
| | - Baker Perry
- Department of Geography and Planning, Appalachian State University, NC, USA
| | - Heather Guy
- School of Earth and Environment, University of Leeds, UK
| | - Ananta Gajurel
- Central Department of Geology, Tribhuvan University, Kathmandu, Nepal
| | - Praveen Kumar Singh
- International Centre for Integrated Mountain Development, Lalitpur, Nepal; CoEDMM, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
| | - Sandra Elvin
- National Geographic Society, 1145 17th St. NW, Washington, DC, USA
| | - Aurora C Elmore
- National Geographic Society, 1145 17th St. NW, Washington, DC, USA
| | - Alex Tait
- National Geographic Society, 1145 17th St. NW, Washington, DC, USA
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Rotiroti M, Bonomi T, Sacchi E, McArthur JM, Stefania GA, Zanotti C, Taviani S, Patelli M, Nava V, Soler V, Fumagalli L, Leoni B. The effects of irrigation on groundwater quality and quantity in a human-modified hydro-system: The Oglio River basin, Po Plain, northern Italy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 672:342-356. [PMID: 30959301 DOI: 10.1016/j.scitotenv.2019.03.427] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 03/26/2019] [Accepted: 03/26/2019] [Indexed: 06/09/2023]
Abstract
For several hundred years, farming in the Po Plain of Italy (46,000 km2, 20 million inhabitants) has been supported by intensive surface irrigation with lake and river water. Despite the longevity of irrigation, its effects on the quality and quantity of groundwater is poorly known and so is investigated here through seasonal measurements of hydraulic heads and water quality in groundwaters, rivers, lake, springs and rainwaters. In the north of the study region, an unconfined coarse-grained alluvial aquifer, infiltration of surface irrigation water, sourced from the Oglio River and low in NO3, contributes much to aquifer recharge (up to 88%, as evidenced by a δ2H-Cl/Br mixing model) and has positive effects on groundwater quality by diluting high concentrations of NO3 (decrease by 17% between June and September). This recharge also helps to maintain numerous local springs that form important local micro-environments. Any increase in water-use efficiency in irrigation will reduce this recharge, imperil the spring environments, and lessen the dilution of NO3 leading to increasing NO3 concentrations in groundwater. These findings can be extended by analogy to the entire Po Plain region and other surface-water-irrigated systems worldwide where inefficient irrigation methods are used and similar hydrogeological features occur.
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Affiliation(s)
- Marco Rotiroti
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, Milan, Italy.
| | - Tullia Bonomi
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, Milan, Italy
| | - Elisa Sacchi
- Department of Earth and Environmental Sciences, University of Pavia, Via Ferrata 1, Pavia, Italy
| | - John M McArthur
- Department of Earth Sciences, University College London, Gower Street, London, United Kingdom
| | - Gennaro A Stefania
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, Milan, Italy
| | - Chiara Zanotti
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, Milan, Italy
| | - Sara Taviani
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, Milan, Italy
| | - Martina Patelli
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, Milan, Italy
| | - Veronica Nava
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, Milan, Italy
| | - Valentina Soler
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, Milan, Italy
| | - Letizia Fumagalli
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, Milan, Italy
| | - Barbara Leoni
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, Milan, Italy
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Colombo N, Gruber S, Martin M, Malandrino M, Magnani A, Godone D, Freppaz M, Fratianni S, Salerno F. Rainfall as primary driver of discharge and solute export from rock glaciers: The Col d'Olen Rock Glacier in the NW Italian Alps. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 639:316-330. [PMID: 29791884 DOI: 10.1016/j.scitotenv.2018.05.098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 06/08/2023]
Abstract
Three hypotheses exist to explain how meteorological variables drive the amount and concentration of solute-enriched water from rock glaciers: (1) Warm periods cause increased subsurface ice melt, which releases solutes; (2) rain periods and the melt of long-lasting snow enhance dilution of rock-glacier outflows; and (3) percolation of rain through rock glaciers facilitates the export of solutes, causing an opposite effect as that described in hypothesis (2). This lack of detailed understanding likely exists because suitable studies of meteorological variables, hydrologic processes and chemical characteristics of water bodies downstream from rock glaciers are unavailable. In this study, a rock-glacier pond in the North-Western Italian Alps was studied on a weekly basis for the ice-free seasons 2014 and 2015 by observing the meteorological variables (air temperature, snowmelt, rainfall) assumed to drive the export of solute-enriched waters from the rock glacier and the hydrochemical response of the pond (water temperature as a proxy of rock-glacier discharge, stable water isotopes, major ions and selected trace elements). An intra-seasonal pattern of increasing solute export associated with higher rock-glacier discharge was found. Specifically, rainfall, after the winter snowpack depletion and prolonged periods of atmospheric temperature above 0 °C, was found to be the primary driver of solute export from the rock glacier during the ice-free season. This occurs likely through the flushing of isotopically- and geochemically-enriched icemelt, causing concomitant increases in the rock-glacier discharge and the solute export (SO42-, Mg2+, Ca2+, Ni, Mn, Co). Moreover, flushing of microbially-active sediments can cause increases in NO3- export.
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Affiliation(s)
- Nicola Colombo
- University of Turin, Department of Earth Sciences, Via Valperga Caluso, 35, 10125 Turin, Italy; Carleton University, Department of Geography and Environmental Studies, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada.
| | - Stephan Gruber
- Carleton University, Department of Geography and Environmental Studies, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - Maria Martin
- University of Turin, Department of Agricultural, Forest and Food Sciences, Largo Paolo Braccini, 2, 10095 Grugliasco, Italy
| | - Mery Malandrino
- University of Turin, Department of Chemistry, Via Pietro Giuria, 5, 10125 Turin, Italy
| | - Andrea Magnani
- University of Turin, Department of Agricultural, Forest and Food Sciences, Largo Paolo Braccini, 2, 10095 Grugliasco, Italy
| | - Danilo Godone
- CNR-IRPI (National Research Council - Research Institute for Geo-Hydrological Protection), Strada delle Cacce, 73, 10135 Turin, Italy
| | - Michele Freppaz
- University of Turin, Department of Agricultural, Forest and Food Sciences, Largo Paolo Braccini, 2, 10095 Grugliasco, Italy
| | - Simona Fratianni
- University of Turin, Department of Earth Sciences, Via Valperga Caluso, 35, 10125 Turin, Italy
| | - Franco Salerno
- CNR-IRSA (National Research Council - Water Research Institute), Via del Mulino, 19, 20047 Brugherio, Italy
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Salerno F, Rogora M, Balestrini R, Lami A, Tartari GA, Thakuri S, Godone D, Freppaz M, Tartari G. Glacier Melting Increases the Solute Concentrations of Himalayan Glacial Lakes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:9150-60. [PMID: 27466701 DOI: 10.1021/acs.est.6b02735] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Over the past two decades, we observed a substantial rise in ionic content that was mainly determined by the sulfate concentration at 20 remote high elevation lakes located in central southern Himalaya. At LCN9, which was monitored on an annual basis for the last 20 years, the sulfate concentrations increased over 4-fold. Among the main causes, we exclude a change in the composition of wet atmospheric deposition, as well as a possible influence of decrease in seasonal snow cover duration, which could have exposed larger basin surfaces to alteration processes. Glacier retreat likely was the main factor responsible for the observed increase of sulfate concentrations. We attribute this chemical changes mainly to the sulfide oxidation processes that occur in subglacial environments. Moreover, we observe that the weakened monsoon of the past two decades has only partially contributed to the lakes enrichment through runoff waters that are more concentrated in solutes or lowering the water table, resulting in more rock exposed to air and enhanced mineral oxidation.
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Affiliation(s)
- Franco Salerno
- CNR-Water Research Institute (IRSA), Via del Mulino 19, Brugherio (MB) 20861, Italy
- Ev-K2-CNR Committee, Via San Bernardino, 145, Bergamo 24126, Italy
| | - Michela Rogora
- CNR-Institute of Ecosystem Study (ISE), Largo Tonolli 50, Verbania Pallanza (VB) 28922, Italy
| | - Raffaella Balestrini
- CNR-Water Research Institute (IRSA), Via del Mulino 19, Brugherio (MB) 20861, Italy
| | - Andrea Lami
- CNR-Institute of Ecosystem Study (ISE), Largo Tonolli 50, Verbania Pallanza (VB) 28922, Italy
- Ev-K2-CNR Committee, Via San Bernardino, 145, Bergamo 24126, Italy
| | - Gabriele A Tartari
- CNR-Institute of Ecosystem Study (ISE), Largo Tonolli 50, Verbania Pallanza (VB) 28922, Italy
| | - Sudeep Thakuri
- CNR-Water Research Institute (IRSA), Via del Mulino 19, Brugherio (MB) 20861, Italy
| | - Danilo Godone
- CNR IRPI-Geohazard Monitoring Group, Strada delle Cacce, 73, 10135 Torino, Italy
| | - Michele Freppaz
- Università di Torino , DISAFA and NatRisk, Largo Paolo Braccini 2, 10095, Grugliasco (TO), Italy
| | - Gianni Tartari
- CNR-Water Research Institute (IRSA), Via del Mulino 19, Brugherio (MB) 20861, Italy
- Ev-K2-CNR Committee, Via San Bernardino, 145, Bergamo 24126, Italy
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