1
|
Liang W, Luo X, Liu Y, Jiao JJ, Lu M, Yan Z, Kuang X. Disentangling external loadings, hydrodynamics and biogeochemical controls on the fate of nitrate in a coastal embayment. JOURNAL OF HAZARDOUS MATERIALS 2024; 478:135465. [PMID: 39163729 DOI: 10.1016/j.jhazmat.2024.135465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 07/27/2024] [Accepted: 08/07/2024] [Indexed: 08/22/2024]
Abstract
Nitrogen, as an essential nutrient, largely contributes to the coastal eutrophication. However, the accurate depiction and evaluation of how external loadings, hydrodynamics, and biogeochemical reactions mediate the occurrence, transport, and transformation of nitrate (NO3-) within coastal embayment still pose ongoing challenges to date. In this study, we took advantage of dual isotopes of NO3- to track external NO3- loadings, radium and dual isotopes of H2O to characterize the influences of hydrodynamic on NO3- transport, δ18O-NO3- and δ18O-H2O along with microbial analysis to explore major NO3- biogeochemical reactions in Tolo Harbour, Hong Kong. The multiple isotopic evidence showed that NO3- in surface harbour water was predominantly contributed by precipitation in wet season and its impact was strengthened by stratification. In dry season, NO3- in the surface harbour water became largely influenced by benthic input and biogeochemical reactions due to intensified vertical mixing. Based on NO3- mass balance model, biogeochemical reaction, especially nitrification, was found to be the major process to secure the closure of NO3- budget and increase NO3- inventory from wet to dry season. Hydrodynamics redistributed the external NO3- loadings and mediated nitrogen biogeochemical reactions, both of which further synergistically regulated the fate of NO3- in the embayment.
Collapse
Affiliation(s)
- Wenzhao Liang
- Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China.
| | - Xin Luo
- Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) China.
| | - Yi Liu
- Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; Earth, Ocean and Atmospheric Sciences (EOAS) Thrust, Function Hub, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou, China.
| | - Jiu Jimmy Jiao
- Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) China.
| | - Meiqing Lu
- Archaeal Biology Center, Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China.
| | - Zhenwei Yan
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China.
| | - Xingxing Kuang
- School of Environmental Science and Engineering, Southern University of Science and Technology, 518055 Shenzhen, China.
| |
Collapse
|
2
|
Cheng KH, Jiao JJ, Lee JHW, Luo X. Synergistic controls of water column stability and groundwater phosphate on coastal algal blooms. WATER RESEARCH 2024; 255:121467. [PMID: 38508041 DOI: 10.1016/j.watres.2024.121467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 03/06/2024] [Accepted: 03/12/2024] [Indexed: 03/22/2024]
Abstract
Algal blooms have been identified as one major threat to coastal safety and marine ecosystem functioning, but the dominant mechanism regulating the formation of algal blooms remains controversial, ranging from physical control (via water column stability), the chemical control (via coastal nutrients) to joint control. Here we leveraged the unique data collected in the Hong Kong water over the annual cycle and past three decades, including direct observations of algal blooms and coastal nutrients and process model output of water column stability, and evaluated the differential competing hypotheses in regulating algal blooms. Our results demonstrate that the joint mechanism rather than the single mechanism effectively predicts all algal blooms. Meanwhile, we observed that the adequate nutrients (phosphate, PO43-) significantly originate from coastal groundwater. The production and fluctuation of PO43- in beach aquifers are primarily governed by groundwater temperature, leading to a sustained and sufficient supply of PO43- in a low groundwater temperature environment. Furthermore, along with submarine groundwater discharge (SGD), the ongoing release of PO43- in groundwater enters coastal waters and serves as sufficient nourishment for promoting algal blooms in coastal areas. These results highlight the importance of both physical and chemical mechanisms, as well as SGD, in regulating coastal algal blooms. These findings have practical implications for the prevention of coastal algal blooms and provide insights into mariculture, water security, and the sustainability of coastal ecosystems.
Collapse
Affiliation(s)
- K H Cheng
- Department of Earth Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China; School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Jiu Jimmy Jiao
- Department of Earth Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
| | - Joseph H W Lee
- Macau Environmental Research Institute, Macau University of Science and Technology, Taipa, Macao, China
| | - Xin Luo
- Department of Earth Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
| |
Collapse
|
3
|
Nakajima T, Kuragano M, Yamada M, Sugimoto R. Comparing nearshore and embayment scale assessments of submarine groundwater discharge: Significance of offshore groundwater discharge as a nutrient pathway. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168068. [PMID: 37914127 DOI: 10.1016/j.scitotenv.2023.168068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/07/2023] [Accepted: 10/21/2023] [Indexed: 11/03/2023]
Abstract
Submarine groundwater discharge (SGD) can influence biogeochemical cycles in coastal seas by delivering nutrients from the seafloor. Comparison between the nearshore and embayment scale assessments of SGD against river water discharge would be crucial for understanding biogeochemical impacts on the coastal seas because the discharge pattern (non-point or point pathway) is different. Here, we quantified SGD contribution to rivers in nutrient budgets at two scales within a coastal embayment (Obama Bay, Japan) by mass balance models of radon and radium isotopes. We then compared the SGD contribution between the two scales by the meta-analysis for regional data sets conducted in nearshore and embayment scales. The estimated SGD rates in the nearshore and embayment scales in the bay were 7.8 cm d-1 and 20.0 cm d-1, indicating that offshore SGD was more significant than nearshore. The ratios of nutrient fluxes derived from SGD to rivers (SGD:River) in the nearshore scale were 1.7 for dissolved inorganic nitrogen (DIN), 3.0 for phosphorus (DIP), and 0.5 for silica (DSi), while those in the embayment scale increased to 10.4 for DIN, 18.5 for DIP, and 3.9 for DSi. This result indicates that SGD-derived nutrients become more important at larger spatial scales. Meta-analysis revealed that the difference in the contribution of SGD to rivers was affected by the seafloor size and there was no significant difference in SGD rates between nearshore and embayment scale studies. However, our regional study shows the site-specific pattern that SGD rates in the embayment scale were higher than those in the nearshore scale. Overall, we clarified that SGD can be a crucial nutrient pathway for coastal embayments regardless of the spatial scales and contribute to coastal nutrient biogeochemistry in more offshore areas.
Collapse
Affiliation(s)
- Toshimi Nakajima
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, Fukui, Japan.
| | - Mao Kuragano
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, Fukui, Japan.
| | - Makoto Yamada
- Faculty of Economics, Ryukoku University, Kyoto, Japan.
| | - Ryo Sugimoto
- Faculty of Marine Biosciences and Technology, Fukui Prefectural University, Fukui, Japan.
| |
Collapse
|
4
|
Liang W, Liu T, Wang Y, Jiao JJ, Gan J, He D. Spatiotemporal-aware machine learning approaches for dissolved oxygen prediction in coastal waters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167138. [PMID: 37734612 DOI: 10.1016/j.scitotenv.2023.167138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 09/09/2023] [Accepted: 09/14/2023] [Indexed: 09/23/2023]
Abstract
Coastal waters face increasing threats from hypoxia, which can have severe consequences for marine life and fisheries. This study aims to develop a machine learning approach for hypoxia monitoring by investigating the effectiveness of four tree-based models, considering spatiotemporal effects in model prediction, and adopting the SHapley Additive exPlanations (SHAP) approach for model interpretability, using the long-term climate and marine monitoring dataset in Tolo Harbour (Zone 1) and Mirs Bay (Zone 2), Hong Kong. The LightBoost model was found to be the most effective for predicting dissolved oxygen (DO) concentrations using spatiotemporal datasets. Considering spatiotemporal effects improved the model's bottom DO prediction performance (R2 increase 0.30 in Zone1 and 0.68 in Zone 2), although the contributions from temporal and spatial factors varied depending on the complexity of physical and chemical processes. This study focused not only on error estimates but also on model interpretation. Using SHAP, we propose that hypoxia is largely influenced by hydrodynamics, but anthropogenic activities can increase the bias of systems, exacerbating chemical reactions and impacting DO levels. Additionally, the high relative importance of silicate (Zone 1:0.11 and Zone 2: 0.19) in the model suggests that terrestrial sources, particularly submarine groundwater discharge, are important factors influencing coastal hypoxia. This is the first machine learning effort to consider spatiotemporal effects in four dimensions to predict DO concentrations, and we believe it contributes to the development of a forecasting tool for alarming hypoxia, combining real-time data and machine learning models in the near future.
Collapse
Affiliation(s)
- Wenzhao Liang
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China; Department of Earth Sciences, The University of Hong Kong, Hong Kong, China
| | - Tongcun Liu
- School of Mathematics and Computer Science, Zhejiang A&F University, Hangzhou 311300, China
| | - Yuntao Wang
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
| | - Jiu Jimmy Jiao
- Department of Earth Sciences, The University of Hong Kong, Hong Kong, China
| | - Jianping Gan
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Ding He
- Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China; State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China.
| |
Collapse
|
5
|
Luo M, Zhang Y, Xiao K, Wang X, Zhang X, Li G, Li H. Effect of submarine groundwater discharge on nutrient distribution and eutrophication in Liaodong Bay, China. WATER RESEARCH 2023; 247:120732. [PMID: 37948905 DOI: 10.1016/j.watres.2023.120732] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/31/2023] [Accepted: 10/10/2023] [Indexed: 11/12/2023]
Abstract
Driven by the anthropogenic activities associated with coastal settlements, eutrophication has become a global issue. Submarine groundwater discharge (SGD) is a significant continuous pathway for transporting nutrients from land to coastal waters, but its influence on eutrophication in Liaodong Bay (LDB) has received limited attention. In this study, radium isotopes and nutrient data from coastal waters were analyzed to evaluate the SGD flux and its implications for potential eutrophication in LDB. We found that the mean concentrations of dissolved inorganic nitrogen (DIN), phosphorous (DIP), and silicate (DSi) in groundwater were higher than those of seawater and river water. Based on 223Ra and 228Ra mass balance models, the SGD fluxes were estimated to be (0.53-2.03) × 109 m3/d, of which the fresh SGD accounted for 4 %-15 %. SGD is a vital invisible source of nutrients, contributing more than 79 % of the total inputs of DIN, DIP, and DSi into LDB. With high DIN/DIP ratios (average=85.8) and large nutrient inputs, SGD may significantly drive the phosphorus limitation and eutrophication in LDB. This study shows that SGD-derived nutrient fluxes should be considered in the assessment of water eutrophication for the formulation of future environmental management protocols in coastal systems.
Collapse
Affiliation(s)
- Manhua Luo
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yan Zhang
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China.
| | - Kai Xiao
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xuejing Wang
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Xiaolang Zhang
- Department of Geosciences, Florida Atlantic University, Boca Raton, FL 33431, United States
| | - Gang Li
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Hailong Li
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China.
| |
Collapse
|
6
|
Chen YL, Zhao LS, Zhou A, Shen SL. Evaluation of environmental impact of red tide around Pearl River Estuary, Guangdong, China. MARINE ENVIRONMENTAL RESEARCH 2023; 185:105892. [PMID: 36689845 DOI: 10.1016/j.marenvres.2023.105892] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 06/17/2023]
Abstract
This paper presents a case study of red tide hazards around the Pearl River Estuary (PRE). Red tide hazards, meteorological data, and seawater monitoring data were collected from 1996 to 2020 at different locations around the PRE to investigate the internal and external factors influencing the occurrence of red tides. The enhancement of the assessment of estuarine trophic status (ASSETS) method enables us to evaluate the effects of meteorological factors and seawater eutrophication status on the red tide risk level. Using ASSETS, we established a framework for red tide risk assessment of the Pearl River Estuary. We analysed the external and internal factors causing the red tide based on meteorological data and seawater monitoring data in the PRE. The results show that the temperature was higher than the annual monthly average temperature of 1.265 °C, and east and north winds at velocities of 3-4 m/s could result in the formation of red tides. However, precipitation inhibits the formation of the red tide in PRE.
Collapse
Affiliation(s)
- Yu-Lin Chen
- Department of Civil Engineering, School of Naval Architecture, Ocean, and Civil Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Lin-Shuang Zhao
- MOE Key Laboratory of Intelligent Manufacturing Technology, Department of Civil and Environmental Engineering, College of Engineering, Shantou University, Shantou, Guangdong, 515063, China.
| | - Annan Zhou
- Discipline of Civil and Infrastructure Engineering, School of Engineering, Royal Melbourne Institute of Technology, Victoria, 3001, Australia
| | - Shui-Long Shen
- MOE Key Laboratory of Intelligent Manufacturing Technology, Department of Civil and Environmental Engineering, College of Engineering, Shantou University, Shantou, Guangdong, 515063, China.
| |
Collapse
|
7
|
Choi Y, Yang K, Lee MY, Youn SH, Son M, Park SR, Kim TH. Factors controlling massive green tide blooms on the coasts of Jeju Island, Korea. MARINE POLLUTION BULLETIN 2023; 186:114446. [PMID: 36502775 DOI: 10.1016/j.marpolbul.2022.114446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/12/2022] [Accepted: 11/25/2022] [Indexed: 06/17/2023]
Abstract
To determine the driving mechanisms between submarine groundwater discharge (SGD) and massive blooms of the green alga Ulva, we examined the magnitude of SGD and SGD-derived nutrient fluxes from November 2019 to July 2020 in Ihotewoo (north) and Bangdu (east) bays, Jeju Island, Korea. The variability of SGD flux at both the sites, where the hydraulic gradient is low, closely followed the daily variability of the tidal range, indicating that SGD flux is primarily driven by tidal pumping. Although the average annual SGD-driven nutrient fluxes were 24-37 % lower in Bangdu Bay than in Ihotewoo Bay, massive Ulva blooms only occurred in Bangdu Bay. A longer residence time (poor water exchange) and continuous SGD input with high dissolved inorganic nitrogen play a significant role in the growth and extentsion of Ulva blooms.
Collapse
Affiliation(s)
- Yujeong Choi
- Research Institute for Basic Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Kyungsun Yang
- Department of Earth Systems and Environmental Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Min Young Lee
- Department of Earth Systems and Environmental Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Suk Hyun Youn
- Oceanic Climate and Ecology Research Division, National Institute of Fisheries Science, Busan 46083, Republic of Korea
| | - Moonho Son
- Oceanic Climate and Ecology Research Division, National Institute of Fisheries Science, Busan 46083, Republic of Korea
| | - Sang Rul Park
- Department of Marine Life Sciences, Jeju National University, Jeju 63243, Republic of Korea
| | - Tae-Hoon Kim
- Department of Earth Systems and Environmental Sciences, Chonnam National University, Gwangju 61186, Republic of Korea.
| |
Collapse
|
8
|
Schubert M, Scholten J, Kreuzburg M, Petermann E, de Paiva ML, Köhler D, Liebetrau V, Rapaglia J, Schlüter M. Radon ( 222Rn) as tracer for submarine groundwater discharge investigation-limitations of the approach at shallow wind-exposed coastal settings. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:798. [PMID: 36114873 PMCID: PMC9482587 DOI: 10.1007/s10661-022-10462-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
Mapping radon (222Rn) distribution patterns in the coastal sea is a widely applied method for localizing and quantifying submarine groundwater discharge (SGD). While the literature reports a wide range of successful case studies, methodical problems that might occur in shallow wind-exposed coastal settings are generally neglected. This paper evaluates causes and effects that resulted in a failure of the radon approach at a distinct shallow wind-exposed location in the Baltic Sea. Based on a simple radon mass balance model, we discuss the effect of both wind speed and wind direction as causal for this failure. We show that at coastal settings, which are dominated by gentle submarine slopes and shallow waters, both parameters have severe impact on coastal radon distribution patterns, thus impeding their use for SGD investigation. In such cases, the radon approach needs necessarily to allow for the impact of wind speed and wind direction not only during but also prior to the field campaign.
Collapse
Affiliation(s)
- Michael Schubert
- Department Catchment Hydrology, Helmholtz Centre for Environmental Research GmbH - UFZ, Permoserstr. 15, Leipzig, 04318, Germany.
| | - Jan Scholten
- Coastal Geology and Sedimentology, Kiel University, Kiel, Germany
| | | | - Eric Petermann
- Federal Office for Radiation Protection (BfS), Berlin, Germany
| | | | - Dennis Köhler
- Alfred-Wegener Institute, Helmholtz Centre for Polar and Ocean Research, Bremen, Germany
| | | | - John Rapaglia
- Department of Biology, Sacred Heart University, Fairfield, CT, United States
| | - Michael Schlüter
- Alfred-Wegener Institute, Helmholtz Centre for Polar and Ocean Research, Bremen, Germany
| |
Collapse
|
9
|
Goyetche T, Luquot L, Carrera J, Martínez-Pérez L, Folch A. Identification and quantification of chemical reactions in a coastal aquifer to assess submarine groundwater discharge composition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155978. [PMID: 35588800 DOI: 10.1016/j.scitotenv.2022.155978] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
In coastal aquifers, two opposite but complementary processes occur: Seawater intrusion (SWI), which may salinize heavily exploited aquifers, and Submarine groundwater discharge (SGD) which transports oligo-elements to the sea. Aquifers are expected to be chemically reactive, both because they provide abundant surfaces to catalyze reactions and the mixing of very different Fresh Water (FW) and Sea Water (SW) promote numerous reactions. Characterizing and quantifying these reactions is essential to assess the quality and composition of both aquifer water, and SGD. Indeed, sampling SGD is difficult, so its composition is usually uncertain. We propose a reactive end-member mixing analysis (rEMMA) methodology based on principal component analysis (PCA) to (i) identify the sources of water and possible reactions occurring in the aquifer and (ii) quantify mixing ratios and the extent of chemical reactions. We applied rEMMA to the Argentona coastal aquifer located North of Barcelona that contains fluvial sediments of granitic origin and overlies weathered granite. The identification of end members (FW and SW) and the spatial distribution of their mixing ratios illustrate the application procedure. The extent of reactions and their spatial distribution allow us to distinguish reactions that occur as a result of mixing from those caused by sediment disequilibrium, which are relevant to recirculated saltwater SGD. The most important reaction is cation exchange, especially between Ca and Na, which promotes other reactions such as Gypsum and Fluorite precipitation. Iron and Manganese are mobilized in the SW portion but oxidized and precipitated in the mixing zone, so that Fe (up to 15 μEq/L) and Mn (up to 10 μEq/L) discharge is restricted to SW SGD. Nitrate is reduced in the mixing zone. The actual reaction amounts are site-specific, but the processes are not, which leads us to conjecture the importance of these reactions to understand the SGD discharge elsewhere.
Collapse
Affiliation(s)
- Tybaud Goyetche
- Institute of Environmental Assessment and Water Research (IDAEA), CSIC, Jordi Girona 18, 08034 Barcelona, Spain; Associated Unit: Hydrogeology group (UPC-CSIC), Spain; Department of Civil and Environment Engineering, Universitat Politècnica de Catalunya (UPC), Jordi Girona 1-3, 08034 Barcelona, Spain.
| | - Linda Luquot
- Géoscience Montpellier, Université de Montpellier, CNRS, Montpellier, France
| | - Jesus Carrera
- Institute of Environmental Assessment and Water Research (IDAEA), CSIC, Jordi Girona 18, 08034 Barcelona, Spain; Associated Unit: Hydrogeology group (UPC-CSIC), Spain
| | - Laura Martínez-Pérez
- Institute of Environmental Assessment and Water Research (IDAEA), CSIC, Jordi Girona 18, 08034 Barcelona, Spain; Associated Unit: Hydrogeology group (UPC-CSIC), Spain; Department of Civil and Environment Engineering, Universitat Politècnica de Catalunya (UPC), Jordi Girona 1-3, 08034 Barcelona, Spain
| | - Albert Folch
- Associated Unit: Hydrogeology group (UPC-CSIC), Spain; Department of Civil and Environment Engineering, Universitat Politècnica de Catalunya (UPC), Jordi Girona 1-3, 08034 Barcelona, Spain
| |
Collapse
|
10
|
Shi X, Luo X, Jiao JJ, Zuo J. Dominance of evaporation on lacustrine groundwater discharge to regulate lake nutrient state and algal blooms. WATER RESEARCH 2022; 219:118620. [PMID: 35598468 DOI: 10.1016/j.watres.2022.118620] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 05/07/2022] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
As global threats to freshwater lakes, eutrophication and harmful algal blooms (HABs) are governed by various biogeochemical, climatological and anthropogenic processes. Groundwater is key to join these processes in regulating HABs, but the underlying mechanisms remain unclear. Here, we leveraged basin-wide field data of Lake Taihu (China's largest eutrophic lake) and global archives, and demonstrate the dominance of evaporation on lacustrine groundwater discharge (LGD) in shallow lakes. We extrapolated decadal LGD and the derived nutrient loadings and found that HABs promptly consume ubiquitous groundwater borne nutrients, leading lake water N: P ratios 2-3 months time lagged behind LGD N: P ratios. We conclude that evaporation dominated LGD is an unraveled but crucial regulator of nutrient states and HABs in shallow lakes, which advocates synergistical studies from both climatological and hydrogeological perspective when restoring lake ecosystems.
Collapse
Affiliation(s)
- Xiaoyan Shi
- Department of Earth Sciences, The University of Hong Kong, Hong Kong; The University of Hong Kong, Zhejiang Institution of Research and Innovation (ZIRI), Hangzhou, China
| | - Xin Luo
- Department of Earth Sciences, The University of Hong Kong, Hong Kong; The University of Hong Kong, Zhejiang Institution of Research and Innovation (ZIRI), Hangzhou, China
| | - Jiu Jimmy Jiao
- Department of Earth Sciences, The University of Hong Kong, Hong Kong; The University of Hong Kong, Zhejiang Institution of Research and Innovation (ZIRI), Hangzhou, China.
| | - Jinchao Zuo
- The University of Hong Kong, Zhejiang Institution of Research and Innovation (ZIRI), Hangzhou, China; The University of Hong Kong, Shenzhen Institution of Research and Innovation (SIRI), Shenzhen, China
| |
Collapse
|
11
|
Cheng KH, Luo X, Jiao JJ, Yu S. Delineating E. coli occurrence and transport in the sandy beach groundwater system by radon-222. JOURNAL OF HAZARDOUS MATERIALS 2022; 431:128618. [PMID: 35278964 DOI: 10.1016/j.jhazmat.2022.128618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/24/2022] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Fecal pollution poses a global threat to environmental safety and ecosystem, but the mechanism of microbial transport and occurrence in the beach groundwater system is still poorly explored. Here, we leveraged one-year field data of Escherichia coli (E. coli) and radon-222 (222Rn) and found that E. coli occurrence and transport in the sandy beach groundwater system can be delineated by 222Rn. The underlying mechanism behind this phenomenon is due to similar half-lives of 222Rn and E. coli in the sandy beach groundwater system. Thus, the unique relationship between 222Rn and E. coli can provide additional critical context to the microbial water quality assessments and ecosystem resilience. Also, the beach aquifer in this study is found to be a vital compartment for E. coli removal. The net E. coli removal/production capacity is identified to be highly impacted by submarine groundwater discharge. Finally, a conceptual model is constructed for a better understanding of the occurrences and characteristics of E. coli and 222Rn at multiple spatial scales. These findings are constructive to mitigate the hazardous influences of microbe on water quality, especially in recreational sandy beaches and mariculture zones.
Collapse
Affiliation(s)
- K H Cheng
- Department of Earth Sciences, The University of Hong Kong, Hong Kong, China
| | - Xin Luo
- Department of Earth Sciences, The University of Hong Kong, Hong Kong, China.
| | - Jiu Jimmy Jiao
- Department of Earth Sciences, The University of Hong Kong, Hong Kong, China
| | - Shengchao Yu
- Department of Earth Sciences, The University of Hong Kong, Hong Kong, China
| |
Collapse
|
12
|
Han D, Currell MJ. Review of drivers and threats to coastal groundwater quality in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150913. [PMID: 34653454 DOI: 10.1016/j.scitotenv.2021.150913] [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] [Received: 07/15/2021] [Revised: 09/22/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
With rapid socio-economic development, China's coastal areas are among the fastest growing and most economically dynamic regions in the world. Under the influence of climate change and human activities, protecting the quality of coastal groundwater has emerged as one of the key environmental and resource management issues for these areas. This paper reviews (for the first time) groundwater quality data for the coastal basins of China, where over 600 million people live, focussing on key inorganic indicators/pollutants; groundwater salinity, nitrate, fluoride, and arsenic. These pollutants present major water quality issues and are also valuable as indicators of wider processes and influences impacting coastal groundwater quality - e.g. saltwater intrusion, agricultural pollution and release of geo-genic contaminants. We discuss the major drivers causing water quality problems in different regions and assess future trajectories and challenges for controlling changes in coastal groundwater quality in China. Multiple processes, including modern and palaeo seawater/brine migration, groundwater pumping for agricultural irrigation, pollution from agrochemical application, rapid development of aquaculture, urban growth, and water transfer projects, may all be responsible (to different degrees) for changes observed in coastal groundwater quality, and associated long-term health and ecological effects. We discuss implications for sustainable coastal aquifer management in China, arguing that groundwater monitoring and contamination control measures require urgent improvement. The evolution and treatment of coastal groundwater quality problems in China will serve as an important warning and example for other countries facing similar pressures, due to climate change, coastal development, and intensification of anthropogenic activity in coming decades.
Collapse
Affiliation(s)
- Dongmei Han
- Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | | |
Collapse
|
13
|
Liu X, Zhang C, Geng R, Lv X. Are oil spills enhancing outbreaks of red tides in the Chinese coastal waters from 1973 to 2017? ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:56473-56479. [PMID: 34057633 DOI: 10.1007/s11356-021-14549-3] [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: 01/13/2021] [Accepted: 05/19/2021] [Indexed: 06/12/2023]
Abstract
Between 1973 and 2017, evidences of red tide outbreaks and oil spill accidents in the Chinese coastal waters were collected. Statistical analysis and multiple regression models were used to determine the relationship between the red tide and the oil spill. Major findings reveal that (1) the frequency of red tides positively correlates to the number of oil spills and the volume of oil spilled as well; (2) the higher percentage of small spills (< 7 tonnes) are more likely to enhance the outbreaks of red tides; (3) both EI Niño and storm events do not show any relationship with red tides; and (4) more severe oil spill with penalty recorded implies a higher possibility to trigger the red tide afterwards. Therefore, oil spill contingency management focusing on small oil spills and mitigating their spill effect by physical measures could be of benefit to decrease the frequency of red tides significantly. For example, it is suggested to carry out physical combat instead of chemical dispersants to remove the spilled small oil in the shallow coastal areas for reducing the outbreak risk of red tides after the oil spill.
Collapse
Affiliation(s)
- Xin Liu
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, People's Republic of China.
- Centre for Ocean Mega-Research of Science, Chinese Academy of Sciences, Yantai, 264003, People's Republic of China.
| | - Chunchang Zhang
- Shanghai Maritime University, Shanghai, 201306, People's Republic of China
| | - Ruiying Geng
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xin Lv
- Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| |
Collapse
|
14
|
Peng T, Zhu Z, Du J, Liu J. Effects of nutrient-rich submarine groundwater discharge on marine aquaculture: A case in Lianjiang, East China Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 786:147388. [PMID: 33984696 DOI: 10.1016/j.scitotenv.2021.147388] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 04/08/2021] [Accepted: 04/23/2021] [Indexed: 06/12/2023]
Abstract
Submarine groundwater discharge (SGD) and associated nutrient have long been received insufficient attention in the aquaculture areas of Lianjiang, East China Sea. In this study, we used 224Ra mass balance model to evaluate the importance of SGD in the aquaculture areas of Lianjiang in different seasons. The results showed that SGD fluxes were 0.14 ± 0.070 m3 m-2 d-1 in July and 0.077 ± 0.040 m3 m-2 d-1 in October 2019, which corresponded to approximately 22% and 32% of the river discharge, respectively. Nevertheless, the dissolved inorganic nitrogen (DIN) and phosphorus (DIP) fluxes contributed by SGD over total nutrient inputs were approximately 58% and 73%, respectively in July, 11% and 33%, respectively in October 2019. The ratio of DIN to DIP in seawater was slightly higher than that derived from SGD in July and significantly lower than that derived from the river and SGD in October, which was prone to profound modulated by shellfish (e.g., clam Ruditapes philippinarum and Sinonovacula constricta) and nori (e.g., Pyropia haitanensis) that selectively acquire nitrogen and phosphorous, suggesting that SGD could affect the nutrient structure and aquaculture activities in Lianjiang. Moreover, the new primary production via SGD yielded (2.47 ± 1.32) × 103 mg C m-2 d-1 in July and (3.52 ± 1.76) × 102 mg C m-2 d-1 in October 2019, which were approximately 8-25% and 10-31% of the production in the entire study area. These meaningful discoveries indicated that SGD and associated nutrient are the predominant regulator of nutrient and aquaculture structure under significant seasonal differences.
Collapse
Affiliation(s)
- Tong Peng
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Zhuoyi Zhu
- School of Oceanography, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Jinzhou Du
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Jianan Liu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China.
| |
Collapse
|
15
|
Wang X, Chen X, Liu J, Zhang F, Li L, Du J. Radon traced seasonal variations of water mixing and accompanying nutrient and carbon transport in the Yellow-Bohai Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 784:147161. [PMID: 33905925 DOI: 10.1016/j.scitotenv.2021.147161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 04/09/2021] [Accepted: 04/11/2021] [Indexed: 06/12/2023]
Abstract
Radon (222Rn) is a natural radioactive tracer widely utilized to evaluate water exchange and mixing processes; however, minimal studies have investigated the 222Rn distribution in the Yellow-Bohai Sea (YBS) and its behavior is poorly understood. In this study, the seasonal distribution of 222Rn in the YBS was investigated. The results found that the 222Rn distribution in surface waters is significantly affected by rivers, while 222Rn activity in bottom waters is highly affected by submarine groundwater discharge. The eddy diffusivity and advection velocities of the YBS were obtained utilizing an improved 1D steady-state 222Rn diffusion-advection model. The average horizontal eddy diffusivities in the wet (August 2015) and dry (November 2014) seasons were 4.54 × 108 and 2.28 × 108 cm2 s-1 in dry season, respectively and the average vertical eddy diffusivity was 4.99 cm2 s-1. The dissolved inorganic nutrient (N, P, and Si) and dissolved inorganic carbon flux outputs from vertical eddy diffusion were determined to be 4.85, 0.29, 3.59, and 61.6 mmol m-2 d-1, respectively. These results demonstrate that eddy diffusion tracing in coastal ocean is conducive to interpreting water mixing processes and can be utilized to understand offshore nutrient and carbon transport better.
Collapse
Affiliation(s)
- Xiaoxiong Wang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Xiaogang Chen
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China; Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China.
| | - Jianan Liu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Fenfen Zhang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China.
| | - Linwei Li
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| | - Jinzhou Du
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China; Institute of Eco-Chongming (IEC), Shanghai 202162, China
| |
Collapse
|
16
|
Liu J, Yu X, Chen X, Du J, Zhang F. Utility of radium quartet for evaluating porewater-derived carbon to a saltmarsh nearshore water: Implications for blue carbon export. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 764:144238. [PMID: 33385654 DOI: 10.1016/j.scitotenv.2020.144238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/23/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Saltmarshes are global hotspots of carbon sequestration and storage and are known as effective blue carbon ecosystems. However, the role of porewater exchange in saltmarshes as a source of carbon to the nearshore waters is still poorly constrained. Herein, we examined the radium quartet, dissolved inorganic (DIC) and organic (DOC) carbon in the porewater and nearshore surface water of Chongming Dongtan saltmarsh, China. Multiple methods based on the radium quartet were applied to estimate the porewater exchange, including the three-endmember model, mass balance model and time series observation. All methods revealed that the porewater exchange rate in Chongming Dongtan saltmarsh equaled 3.37 ± 1.23 cm d-1. The porewater-derived DIC and DOC fluxes were then estimated to be (1.51 ± 0.64) × 107 and (9.97 ± 6.96) × 105 mol d-1, respectively, which correspondingly made up 64.6% and 35.6%, of the total inputs into the Chongming Dongtan saltmarsh nearshore water. Considering the intertidal area covered by saltmarsh vegetation, carbon export through the porewater exchange was 3.87 ± 1.55 g C m-2 d-1, and was 1.2-fold greater than the carbon burial rate, accounting for approximately 29% of carbon outwelling in Chongming Dongtan saltmarsh. This study highlights the significance of porewater exchange for evaluating carbon sequestration capacity, and suggests that porewater exchange should not be overlooked in blue carbon assessments of saltmarshes.
Collapse
Affiliation(s)
- Jianan Liu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Xueqing Yu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Xiaogang Chen
- Key Laboratory of Coastal Environment and Resources Research of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China; Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Jinzhou Du
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China; Institute of Eco-Chongming (IEC), Shanghai 202162, China.
| | - Fenfen Zhang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| |
Collapse
|
17
|
Wang X, Zhang Y, Luo M, Xiao K, Wang Q, Tian Y, Qiu W, Xiong Y, Zheng C, Li H. Radium and nitrogen isotopes tracing fluxes and sources of submarine groundwater discharge driven nitrate in an urbanized coastal area. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 763:144616. [PMID: 33385844 DOI: 10.1016/j.scitotenv.2020.144616] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/03/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
The quantitative evaluations of nutrients delivered by submarine groundwater discharge (SGD) have been widely conducted worldwide, but sources of nutrients in the discharged submarine groundwater remain unclear. Identifying these sources of nutrients is essential to the protection and management of marine ecological environments. This study aims to evaluate the magnitudes of SGD and the associated nitrate in the Guangdong-Hongkong-Macao Greater Bay Area (GHM Greater Bay Area), China, and identify the sources of SGD-driven nitrate in this region using radioactive radium (Ra) isotopes (223Ra, 224Ra, and 228Ra) and stable nitrogen (N) and oxygen (O) isotope composition of nitrate (δ15N-NO3- and δ18O-NO3-). The results of the Ra mixing model show that the estimated SGD and the associated nitrate fluxes into the Greater Bay Area are (9.15 ± 1.26) × 108 m3/d and (3.77 ± 0.52) × 107 mol/d, respectively, both of which are comparable to the contributions from the Pearl River. Combing NO3- dual isotopic signatures of sampled coastal groundwater and five kinds of potential nitrate sources, we found that ammonium (NH4+) fertilizer and natural soil N are the two main sources of nitrate in discharged submarine groundwater and rivers. No anthropogenic inputs from manure or sewage waste were identified. This study provides significant insights into the establishment of effective management strategies for controlling SGD-nutrients into the bay and protecting the marine ecological environment.
Collapse
Affiliation(s)
- Xuejing Wang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Yan Zhang
- MOE Key Laboratory of Groundwater Circulation & Environment Evolution and School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| | - Manhua Luo
- MOE Key Laboratory of Groundwater Circulation & Environment Evolution and School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| | - Kai Xiao
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Qianqian Wang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yong Tian
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenhui Qiu
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Ying Xiong
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Chunmiao Zheng
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Hailong Li
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; MOE Key Laboratory of Groundwater Circulation & Environment Evolution and School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China.
| |
Collapse
|
18
|
Douglas AR, Murgulet D, Montagna PA. Hydroclimatic variability drives submarine groundwater discharge and nutrient fluxes in an anthropogenically disturbed, semi-arid estuary. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142574. [PMID: 33069908 DOI: 10.1016/j.scitotenv.2020.142574] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/03/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
Nutrient budgets in semi-arid estuaries, with ephemeral freshwater inflows and limited nutrient sources, are likely incomplete if contributions from submarine groundwater discharge (SGD) are not included. Here, the relative importance of saline/recirculated SGD-derived nutrient fluxes spatiotemporal variability to the overall nutrient budget is quantified for Nueces Bay, Texas, U.S.A., across hydroclimatic conditions ranging from drought to normal, to flood. On average, 67% of the variance in water quality is due to temporal differences while 16% is explained by spatial differences. Principal component analysis (PCA) reveals three principal components: freshwater inflow (PC1 28.8%), saline/recirculated SGD and recycled nitrogen (PC2 15.6%), and total SGD and "new" nitrogen (PC3 11.2%). Total SGD porewater fluxes ranged from 29.9-690.3 mmol∙m-2d-1 for ammonium, 0.21-18.7 mmol∙m-2d-1 for nitrite+nitrate, 3.1-51.3 mmol∙m-2d-1 for phosphate, 57.1-719.7 mmol∙m-2d-1 for silicate, and 95.9-36,838.5 mmol∙m-2d-1 for dissolved organic carbon. Total and saline/recirculated SGD fluxes were on average 150-26,000 and 5.8-466 times, respectively, greater than surface runoff fluxes across all seasons. Nitrogen (N) enrichment in porewater occurs near the agricultural fields because of soil N flushing and percolation to groundwater, which facilitates N-rich groundwater fluxes. There were substantial "new" N inputs from terrestrial groundwater following precipitation while saline/recirculated SGD of recycled N accounts for only <4% of total SGD inputs. The "new" N inputs occur in the river and river mouth during flooding, and near the north shore where topography and hydraulic gradients are steeper during drought. Thus, while significant inputs of N may be associated with atmospheric deposition, or remineralization in the porewater, groundwater is the highest contributor to the nutrient budget in Nueces Bay. This result implies that nutrient management strategies should focus on land-use practices to reduce N contamination of shallow groundwater and subsequent contamination of estuaries.
Collapse
Affiliation(s)
- Audrey R Douglas
- Center for Water Supply Studies, Texas A&M University-Corpus Christi, Corpus Christi, TX 78412, USA.
| | - Dorina Murgulet
- Center for Water Supply Studies, Texas A&M University-Corpus Christi, Corpus Christi, TX 78412, USA.
| | - Paul A Montagna
- Harte Research Institute for Gulf of Mexico Studies, Texas A&M University-Corpus Christi, Corpus Christi, TX 78412, USA
| |
Collapse
|
19
|
Chen X, Ye Q, Sanders CJ, Du J, Zhang J. Bacterial-derived nutrient and carbon source-sink behaviors in a sandy beach subterranean estuary. MARINE POLLUTION BULLETIN 2020; 160:111570. [PMID: 32861939 DOI: 10.1016/j.marpolbul.2020.111570] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/01/2020] [Accepted: 08/11/2020] [Indexed: 06/11/2023]
Abstract
Microbial communities in subterranean estuaries play important roles in the biogeochemical cycle. However, the microorganisms associated with biogeochemical behaviors in subterranean estuaries have received little attention. Here, the bacterial communities were compared between the fresh and saline groundwater in a subterranean estuary. Correlation analysis between bacterial groups and salinity indicated that different species represented different groundwater types. The key bacterial groups found along the subterranean estuaries have been shown to influence organic pollutant degradation and nitrate utilization. These species may be potential candidates for the in situ bioremediation of subterranean estuaries that are contaminated with pollutants. The utilization of nitrate and organic pollutants by bacteria in subterranean estuaries serves as a nitrate sink and inorganic carbon source. Our results show the role of bacteria in remediating pollutants through submarine groundwater discharge (SGD) to the coastal ocean, and specific species may be helpful in selecting reasonable groundwater end-members and reducing SGD uncertainties.
Collapse
Affiliation(s)
- Xiaogang Chen
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China; School of Engineering, Westlake University, Hangzhou 310024, China
| | - Qi Ye
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China.
| | - Christian J Sanders
- National Marine Science Centre, Southern Cross University, Coffs Harbour, NSW 2450, Australia
| | - Jinzhou Du
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China; Institute of Eco-Chongming (IEC), Shanghai 202162, China
| | - Jing Zhang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| |
Collapse
|
20
|
Wang X, Li H, Zhang Y, Zheng C, Gao M. Investigation of submarine groundwater discharge and associated nutrient inputs into Laizhou Bay (China) using radium quartet. MARINE POLLUTION BULLETIN 2020; 157:111359. [PMID: 32658708 DOI: 10.1016/j.marpolbul.2020.111359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/03/2020] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
Radium is widely used to estimate flushing time, submarine groundwater discharge (SGD), and submarine fresh groundwater discharge (SFGD), however there are important sources of uncertainty in current methods. Here an improved method is proposed, incorporating all radium quartet information to estimate flushing time, SFGD, SGD, and associated nutrient fluxes during wet and dry seasons in Laizhou Bay, China. Both SGD and SFGD in dry season are comparable to that in wet season, likely due to higher groundwater hydraulic gradients resulting from higher groundwater table and lower mean sea level in dry season. Estimated dry and wet season SFGD are of the same order of magnitude as the annually-averaged Yellow River discharge, highlighting SFGD's importance to the bay environment. Nutrient inputs into Laizhou Bay were estimated for the wet season, suggesting that SGD-derived nutrients are indeed important and significant for coastal environments compared to local river discharge estimates.
Collapse
Affiliation(s)
- Xuejing Wang
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Hailong Li
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences-Beijing, Beijing 100083, China; School of Water Resources and Environment, China University of Geosciences-Beijing, Beijing 100083, China.
| | - Yan Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences-Beijing, Beijing 100083, China; School of Water Resources and Environment, China University of Geosciences-Beijing, Beijing 100083, China
| | - Chunmiao Zheng
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Maosheng Gao
- Qingdao Institute of Marine Geology, Qingdao 266071, China
| |
Collapse
|
21
|
Cheng KH, Luo X, Jiao JJ. Two-decade variations of fresh submarine groundwater discharge to Tolo Harbour and their ecological significance by coupled remote sensing and radon-222 model. WATER RESEARCH 2020; 178:115866. [PMID: 32380295 DOI: 10.1016/j.watres.2020.115866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 04/20/2020] [Accepted: 04/22/2020] [Indexed: 06/11/2023]
Abstract
Although submarine groundwater discharge (SGD) comprises an insignificant proportion of the global hydrologic cycle, it contributes significantly to chemical fluxes into the coastal waters due to concentrated constituents in coastal groundwater. Large nutrient loadings derived from SGD can lead to a series of environmental and ecological problems such as algal blooms, resulting in water discoloration, severe dissolved oxygen depletion, and eventually beach closures and massive fish kills. Previous studies have demonstrated the relationship between algal blooms and SGD obtained from direct measurement with seepage meters or from geo-tracer (i.e., radon and radium) based models; these traditional methods are time-consuming, laborious and point monitoring, and can hardly achieve a high spatiotemporal resolution SGD estimation, which is vital in revealing the effects of SGD to algal blooms over a long period. Alternatively, remote sensing methods for high spatiotemporal resolution SGD localization and quantification are applicable and effective. The temperature difference or anomaly between groundwater and coastal water extracted from satellite thermal images can be used as the indicator to localize and detect SGD especially its fresh component (or fresh SGD). In this study, multi-year (2005, 2011 and 2018) radon samples in Tolo Harbour were used to train regression models between in-situ radon (Rn) activity and the temperature anomaly by Landsat satellite thermal images. The models were used to estimate two-decade variations of fresh SGD in Tolo Harbour. The synergistic analysis between the time series of fresh SGD derived from regression models and high spatiotemporal resolution ecological metrics (chlorophyll-a, algal cell counts, and E.coli) leads to the findings that the increase of the fresh SGD associated with high nutrient concentrations is witnessed 10-20 days before the observations of algal bloom events. This study makes the first attempt to demonstrate the strong relation between the SGD and algal blooms over a vicennial span, and also provides a cost effective and robust technique to estimate SGD on a bay scale.
Collapse
Affiliation(s)
- K H Cheng
- Department of Earth Science, The University of Hong Kong, Hong Kong, China
| | - Xin Luo
- Department of Earth Science, The University of Hong Kong, Hong Kong, China
| | - Jiu Jimmy Jiao
- Department of Earth Science, The University of Hong Kong, Hong Kong, China.
| |
Collapse
|
22
|
Erostate M, Huneau F, Garel E, Ghiotti S, Vystavna Y, Garrido M, Pasqualini V. Groundwater dependent ecosystems in coastal Mediterranean regions: Characterization, challenges and management for their protection. WATER RESEARCH 2020; 172:115461. [PMID: 31951946 DOI: 10.1016/j.watres.2019.115461] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/24/2019] [Accepted: 12/30/2019] [Indexed: 06/10/2023]
Abstract
Coastal lagoons deliver a wide range of valuable ecosystem goods and services. These ecosystems, that are often maintained by direct or indirect groundwater supplies, are collectively known as groundwater dependent ecosystems (GDEs). The importance of groundwater supplies is greatly exacerbated in coastal Mediterranean regions where the lack of surface water and the over-development of anthropogenic activities critically threaten the sustainability of coastal GDEs and associated ecosystem services. Yet, coastal GDEs do not benefit from a legal or managerial recognition to take into account their specificity. Particular attention should be paid to the characterization of environmental and ecological water requirements. The hydrogeological knowledge about the management and behavior of coastal aquifers and GDEs must be strengthened. These investigations must be supplemented by a stronger assessment of potential contaminations to develop local land-uses and human activities according to the groundwater vulnerability. The quantitative management of water resources must also be better supervised and/or more constrained in order to ensure the water needs necessary to maintain coastal GDEs. The transdisciplinary approach between hydrogeology, hydrology, social sciences and law is essential to fully understand the socio-economic and environmental complexity of coastal GDEs. Priority must now be given to the development of an appropriate definition of coastal GDEs, based on a consensus between scientists and lawyers. It is a necessary first step to develop and implement specific protective legislation and to define an appropriate management scale. The investment and collaboration of local water users, stakeholders and decision-makers need to be strengthened through actions to favor exchanges and discussions. All water resources in the coastal areas should be managed collectively and strategically, in order to maximize use efficiency, reduce water use conflicts and avoid over-exploitation. It is important to continue to raise public awareness of coastal aquifers at the regional level and to integrate their specificities into coastal zone management strategies and plans. In the global context of unprecedented anthropogenic pressures, hydro-food crises and climate change, environmental protection and preservation of coastal GDEs represents a major challenge for the sustainable socio-economic and environmental development of Mediterranean coastal zones.
Collapse
Affiliation(s)
- M Erostate
- Université de Corse Pascal Paoli, Faculté des Sciences et Techniques, Département d'Hydrogéologie, Campus Grimaldi, BP 52, F-20250, Corte, France; CNRS, UMR 6134, SPE, F-20250, Corte, France.
| | - F Huneau
- Université de Corse Pascal Paoli, Faculté des Sciences et Techniques, Département d'Hydrogéologie, Campus Grimaldi, BP 52, F-20250, Corte, France; CNRS, UMR 6134, SPE, F-20250, Corte, France
| | - E Garel
- Université de Corse Pascal Paoli, Faculté des Sciences et Techniques, Département d'Hydrogéologie, Campus Grimaldi, BP 52, F-20250, Corte, France; CNRS, UMR 6134, SPE, F-20250, Corte, France
| | - S Ghiotti
- CNRS, Laboratoire Art-Dev UMR 5281, Université Paul Valéry Montpellier 3, Route de Mende, 34190 Montpellier cedex 5, France
| | - Y Vystavna
- Institute of Hydrobiology, Biology Centre of the Academy of Sciences of the Czech Republic, Na Sádkách 7, 37005, České Budějovice, Czech Republic
| | - M Garrido
- Office de l'Environnement de la Corse, 14 Avenue Jean Nicoli, 20250, Corte, France
| | | |
Collapse
|
23
|
Liang W, Liu Y, Jiao JJ, Luo X. The dynamics of dissolved inorganic nitrogen species mediated by fresh submarine groundwater discharge and their impact on phytoplankton community structure. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 703:134897. [PMID: 31731157 DOI: 10.1016/j.scitotenv.2019.134897] [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: 06/17/2019] [Revised: 10/07/2019] [Accepted: 10/07/2019] [Indexed: 06/10/2023]
Abstract
Submarine groundwater discharge (SGD)-driven nutrient inputs have long been speculated to sustain the high frequency of red tide occurrence in Tolo Harbour, Hong Kong, for its larger flux and higher nutrient loadings than river discharge. Based on analysis of high resolution time series biogeochemical and climatological data from 2000 to 2015, fresh SGD-derived dissolved inorganic nitrogen (DIN) is found to be a significant regulator of the annual cycle of phytoplankton community structure in the harbour. In the wet season, fresh SGD supplies nutrients with NH4+:NO3- ratio < 1 to the seawater, meanwhile creates an intensive vertical stratification environment. As a result, diatom which is a NO3- specialist, is prone to be the major group in the harbour. Fresh SGD delivers a same orders of magnitude of DIN as river and precipitation, but it is more important to phytoplankton community structure dynamics because fresh groundwater has smaller NH4+:NO3- ratio that significantly changes the ratio in the harbour. In the dry season, with the decline of fresh SGD and the ease of stratification, vertical mixing uplifts the nutrient (NH4+:NO3- ratio > 1) released from the bottom sediment leading to a NH4+ dominant environment in water column. Dinoflagellate and other groups then become dominant species of phytoplankton in the harbour. Fresh SGD has a major influence on the NH4+:NO3- ratio in the seawater compared to tide-driven SGD, even though the latter contributes a larger proportion SGD. Tide-driven SGD also produces NH4+ and NO3-, but NH4+:NO3- ratio are mainly subject to the beach environment (bare/mangrove beach), which does not change much seasonally, thus dominant DIN species do not change significantly throughout a year. In a conclusion, fresh SGD plays the most important role among all the endmembers in regulating the DIN composition in Tolo Harbour and its fluctuation mediates the phytoplankton community structure.
Collapse
Affiliation(s)
- Wenzhao Liang
- Department of Earth Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China; Shenzhen Research Institute, The University of Hong Kong, Shenzhen, China.
| | - Yi Liu
- Department of Earth Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China; Shenzhen Research Institute, The University of Hong Kong, Shenzhen, China; Department of Civil and Environmental Engineering, Western University, London, Ontario, Canada.
| | - Jiu Jimmy Jiao
- Department of Earth Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China; Shenzhen Research Institute, The University of Hong Kong, Shenzhen, China.
| | - Xin Luo
- Department of Earth Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China; Shenzhen Research Institute, The University of Hong Kong, Shenzhen, China.
| |
Collapse
|
24
|
Wang Q, Li H, Zhang Y, Wang X, Xiao K, Zhang X, Huang Y, Dan SF. Submarine groundwater discharge and its implication for nutrient budgets in the western Bohai Bay, China. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 212:106132. [PMID: 31885366 DOI: 10.1016/j.jenvrad.2019.106132] [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: 09/21/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 06/10/2023]
Abstract
Submarine groundwater discharge (SGD) supplies substantial quantities of nutrients from land to oceans. However, SGD and associated nutrient fluxes have long been ignored in Bohai Bay, which is subjected to the serious environmental problem. Here, we investigated the concentrations of radon (222Rn) and nutrients in groundwater and surface water in the western Bohai Bay during May 2017. The flushing time in the bay was estimated to be 38.8-58.3 days based on tidal prism model. The SGD flux was estimated to be 7.3 ± 4.8 cm d-1 based on 222Rn mass balance model. The SGD associated nutrient fluxes were estimated to be (6.3 ± 4.1) × 107 mol d-1 for dissolved inorganic nitrogen (DIN), (1.2 ± 0.8) × 106 mol d-1 for dissolved inorganic phosphorus (DIP) and (7.5 ± 4.9) × 107 mol d-1 for dissolved inorganic silicon (DSi). By establishing nutrient budgets, we found that SGD was a major source, contributing 80.8% of all source for DIN, 90.7% of all source for DIP and 78.4% of all source for DSi into the western Bohai Bay. This study shows that SGD associated nutrient fluxes may have significant impact on nutrient budgets in the western Bohai Bay.
Collapse
Affiliation(s)
- Qianqian Wang
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution and School of Water Resources and Environment, China University of Geosciences-Beijing, Beijing, 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences-Beijing, Beijing, 100083, China
| | - Hailong Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences-Beijing, Beijing, 100083, China; Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control and School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
| | - Yan Zhang
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution and School of Water Resources and Environment, China University of Geosciences-Beijing, Beijing, 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences-Beijing, Beijing, 100083, China
| | - Xuejing Wang
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control and School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Kai Xiao
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control and School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xiaolang Zhang
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control and School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Yimeng Huang
- Sichuan Provincial Earthquake Bureau, Chengdu, 610041, China
| | - Solomon Felix Dan
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education/Institute for Advanced Ocean Study, Ocean University of China, Qingdao, 266100, China
| |
Collapse
|
25
|
Xiao K, Li G, Li H, Zhang Y, Wang X, Hu W, Zhang C. Combining hydrological investigations and radium isotopes to understand the environmental effect of groundwater discharge to a typical urbanized estuary in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 695:133872. [PMID: 31422322 DOI: 10.1016/j.scitotenv.2019.133872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/08/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Pollution of urbanized rivers with excess nutrients due to groundwater discharge is an increasing environmental concern worldwide. Dan'ao river, a typical urbanized river in the Guangdong-Hong Kong-Macao Greater Bay Area, is experiencing heavy water pollution. However, the groundwater-derived nutrient loads had not yet been thoroughly quantified. In order to quantify the contribution of groundwater-derived nutrient inputs, we combined the methods of hydrological investigations and radium isotopes. Groundwater and river water samples were collected from the river upstream to the estuary for the analyses of radium quartets and nutrients including DIN, DIP and DSi. The results showed that the radium activities in both surface water and groundwater decreased from the estuary to the upstream. The groundwater discharge rate was estimated by the radium mass balance model using short-lived radium isotopes (223Ra and 224Ra). The estimated groundwater discharge rate ranged from 1.99 × 105 to 6.67 × 105 m3 d-1, comparable to the upstream river discharge rate of 4.23 × 105 m3 d-1. The groundwater-derived nutrient fluxes were 165.66-554.98 mmol m-2 d-1 for DIN, 2.47-8.26 mmol m-2 d-1 for DIP and 63.73-213.49 mmol m-2 d-1 for DSi, respectively. They contributed 19%~44% DIN, 16%~39% DIP, and 31%~60% DSi of all the nutrient inputs into the Dan'ao River, respectively. In addition, the nutrient inputs by groundwater discharge has an average DIN:DIP ratio of as high as 190, which is able to potentially affect the riverine and marine nutrient structures. These findings may provide useful information for designing control strategies for reducing massive nutrient inputs to Dan'ao River in the future.
Collapse
Affiliation(s)
- Kai Xiao
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, PR China
| | - Gang Li
- China Institute of Geo-Environment Monitoring, Beijing 100081, PR China; Hebei Key Laboratory of Geological Resources and Environment Monitoring and Protection,Shijiazhuang 050021, PR China
| | - Hailong Li
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, PR China.
| | - Yan Zhang
- School of Water Resources and Environmental Science, China University of Geosciences, Beijing 100083, PR China
| | - Xuejing Wang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, PR China
| | - Wenli Hu
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, PR China
| | - Chengcheng Zhang
- Northwest Institute of Nuclear Technology, Xian 710024, PR China
| |
Collapse
|
26
|
Wang Q, Li H, Zhang Y, Wang X, Zhang C, Xiao K, Qu W. Evaluations of submarine groundwater discharge and associated heavy metal fluxes in Bohai Bay, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 695:133873. [PMID: 31422319 DOI: 10.1016/j.scitotenv.2019.133873] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 08/09/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Submarine groundwater discharge (SGD) has been recognized as an important source of dissolved heavy metals to the coastal ocean. Bohai Bay, the second largest bay of Bohai Sea in China, is subjected to serious environmental problems. However, SGD and SGD-derived heavy metal fluxes in the bay are seldom reported. In this study, we present mass balance models considering the radium losses caused by recirculated seawater to estimate water age, SGD and SGD-derived heavy metal fluxes in Bohai Bay during May 2017. The water age is estimated to be 56.7-85.0 days based on tidal prism model. By combining water and salt mass balance models, submarine fresh groundwater discharge (SFGD) is estimated to be (3.5-9.3) × 107 m3 d-1. The SGD flux estimated by the radium mass balance models is (3.2-7.7) × 108 m3 d-1, an order of magnitude larger than the discharge of the Yellow River during the sampling period. SGD-derived heavy metal fluxes were estimated to be (0.2-6.0) × 107 mol d-1 for Fe, (1.2-2.7) × 107 mol d-1 for Mn, (3.0-8.2) × 105 mol d-1 for Zn, (2.7-7.4) × 104 mol d-1 for Cr and (0.6-1.8) × 103 mol d-1 for Cd, which are significantly higher than those from local rivers. This study reveals that SGD is a significant source of heavy metals (Mn, Zn and Fe) into Bohai Bay, which may have important influences on the metal budgets and ecological environments in coastal areas.
Collapse
Affiliation(s)
- Qianqian Wang
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution and School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing 100083, China
| | - Hailong Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing 100083, China; Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control and School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Yan Zhang
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution and School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing 100083, China.
| | - Xuejing Wang
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control and School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | | | - Kai Xiao
- Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control and School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenjing Qu
- School of Water Resources and Environment, Hebei GEO University, Shijiazhuang 050031, China
| |
Collapse
|
27
|
Maguire TJ, Fulweiler RW. Urban groundwater dissolved silica concentrations are elevated due to vertical composition of historic land-filling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 684:89-95. [PMID: 31150879 DOI: 10.1016/j.scitotenv.2019.05.272] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/16/2019] [Accepted: 05/18/2019] [Indexed: 06/09/2023]
Abstract
Human influences on global silicon (Si) cycling include land-use change, deforestation, and wastewater discharge. Here we quantified the effect of urban expansion and historic land fill on dissolved silica (DSi) concentrations in urban groundwater in a northern temperate city. We hypothesized that historical land use, fill material, and urban infrastructure buried below cities create a unique anthropogenic geology which acts as a DSi source. We found that concentrations of DSi in urban groundwater are significantly higher than those from non-urban environments. We also found that historic land-use variables out-perform traditional topographic variables predicting urban DSi concentrations. We show that higher groundwater DSi concentrations result in increased subterranean groundwater discharge (SGD) fluxes, thereby altering coastal receiving water DSi availability. Further, we demonstrate that accounting for urban SGD DSi fluxes globally, could increase DSi SGD export by 20%. Together these results call for a re-evaluation of anthropogenic impacts on the global Si cycle.
Collapse
Affiliation(s)
- Timothy J Maguire
- Biology Department, Boston University, 5 Cummington Mall, Boston, MA 02215, United States of America.
| | - Robinson W Fulweiler
- Biology Department, Boston University, 5 Cummington Mall, Boston, MA 02215, United States of America; Earth and Environment Department, Boston University, 685 Commonwealth Avenue, Boston, MA 02215, United States of America
| |
Collapse
|
28
|
Bacterial and Archaeal Assemblages from Two Size Fractions in Submarine Groundwater Near an Industrial Zone. WATER 2019. [DOI: 10.3390/w11061261] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Nutrients and organic pollutants transported by submarine groundwater discharge (SGD) play a significant role in controlling water quality, and can lead to the concerned deleterious effects on marine ecosystems. Subterranean estuaries are complicated habitats of diverse microbial communities that mediate different biogeochemical processes. However, there is less information on how microorganisms mediate biogeochemical cycles in the submarine groundwater system. In this study, we investigated the changes in bacterial and archaeal assemblages from two size fractions (0.2–0.45 μm and >0.45 μm) in the submarine groundwater of Qinzhou Bay, China. Phylogenetic analysis showed that Bathyarchaeota was dominant in archaeal communities in the >0.45 μm size fraction, but was seldom in the 0.2–0.45 μm fraction. The co-occurrence of sequences belonging to Bathyarchaeota and Methanosaeta was found in the >0.45 μm size fraction. Since a gene encoding acetate kinase of Bathyarchaeota is involved in acetate production, and acetate is also a necessary growth factor for Methanosaeta, the acetate produced by Bathyarchaeota can provide food or energy sources for Methanosaeta in this very >0.45 μm size fraction. The most abundant bacterial sequences in the >0.45 μm size fraction was closely related to biomineral iron-oxidizing Gallionella spp., whereas the dominant bacterial sequences in the 0.2–0.45 μm fraction were affiliated with Limnohabitans spp., which can utilize dissolved organic matter as an important source of growth substrates. Notably, approximately 10% of the bacterial sequences in both of the two size fractions belonged to Novosphingobium spp., which plays an important role in the degradation of pollutants, especially aromatic compounds. Furthermore, the predictive functional profiling also revealed that the pathways involved in the degradation of aromatic compounds by both bacteria and archaea were identified. The presence of nutrients or pollutants in our study site provides different substrates for the growth of the specific microbial groups; in turn, these microbes may help to deplete pollutants to the ocean through submarine groundwater. We suggest that these specific microbial groups could be potential candidates for effective in situ bioremediation of groundwater ecosystems.
Collapse
|
29
|
Liu Y, Not C, Jiao JJ, Liang W, Lu M. Tidal induced dynamics and geochemical reactions of trace metals (Fe, Mn, and Sr) in the salinity transition zone of an intertidal aquifer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 664:1133-1149. [PMID: 30901786 DOI: 10.1016/j.scitotenv.2019.01.374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/16/2019] [Accepted: 01/16/2019] [Indexed: 06/09/2023]
Abstract
Biogeochemical reactions in an intertidal aquifer influences the submarine groundwater discharge (SGD) associated trace metal flux to the ocean. Tidal fluctuation greatly affects the physical mixing, and biogeochemical transformation of trace metals in the intertidal aquifer. This study presents the dynamics of trace metals (Fe, Mn, and Sr) and the production of Fe2+ in the salinity transition zone is discovered. The variations of Fe2+ are led by the shifts of both physical mixing and biogeochemical reaction during tidal fluctuation. The transformation from amorphous Fe(OH)3 to FeS is the main reason for the enrichment of Fe2+ in the zone with a salinity of 0.5-10. Mn behaves much less active than Fe in the intertidal aquifer due to the very limited Mn in the solid phase and the major driving force of Mn2+ variation is the physical mixing rather than geochemical reaction. Sr2+ behaves conservatively and shows a synchronous with salinity in the salinity transition zone. This study found that Fe2+ precipitates in a form not limited to Fe (hydro)oxides and the FeS minerals is the most possible form of precipitation in reduced aquifers. In that case, only a small part of Fe2+ discharges to the sea associated with SGD, but Mn2+ has a comparatively conservative property during the transport in the intertidal aquifer and majority of the Mn2+ originated from fresh groundwater will discharge with SGD in this study. The biogeochemical transformation pathways of Fe and Mn observed in this study provides insights into the cycles of Fe and Mn in an intertidal aquifer, which is of significance to accurately estimate the SGD derived Fe and Mn fluxes to the ocean.
Collapse
Affiliation(s)
- Yi Liu
- Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; Shenzhen Research Institute, The University of Hong Kong, Shenzhen, China.
| | - Christelle Not
- Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; The Swire Institute for Marine Science, The University of Hong Kong, Cap d'Aguilar, Hong Kong, China
| | - Jiu Jimmy Jiao
- Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; Shenzhen Research Institute, The University of Hong Kong, Shenzhen, China.
| | - Wenzhao Liang
- Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; Shenzhen Research Institute, The University of Hong Kong, Shenzhen, China
| | - Meiqing Lu
- Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| |
Collapse
|
30
|
Luo X, Jiao JJ, Moore WS, Cherry JA, Wang Y, Liu K. Significant chemical fluxes from natural terrestrial groundwater rival anthropogenic and fluvial input in a large-river deltaic estuary. WATER RESEARCH 2018; 144:603-615. [PMID: 30096687 DOI: 10.1016/j.watres.2018.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 06/12/2018] [Accepted: 07/03/2018] [Indexed: 06/08/2023]
Abstract
The shores of the Pearl River estuary are home to 35 million people. Their wastes are discharged into the large river delta-front estuary (LDE), one of the most highly polluted systems in the world. Here we construct a radium reactive transport model to estimate the terrestrial groundwater discharge (TGD) into the highly urbanized Pearl River LDE. We find the TGD comprises only approximately 0.9% in term of water discharge compared to the river discharge. The TGD in the Pearl River LDE delivers significant chemical fluxes to the coast, which are comparable to the fluvial loadings from Pearl River and other world major rivers. Of particular importance is the flux of ammonium because of its considerable role in Pearl River estuary eutrophication and hypoxia. Unlike the ammonium in many other aquifers, the ammonium in the Pearl River aquifer system is natural and originated from organic matter remineralization by sulfate reduction in the extremely reducing environment. The TGD derived NH4+ is as much as 5% of the upstream Pearl River fluvial loading and 42% of the anthropogenic inputs. This high groundwater NH4+ flux may greatly intensify the eutrophication, shift the trophic states, and lead to alarming hypoxia within the affected ecosystems in the Pearl River LDE. The large TGD derived chemical fluxes will lead to deterioration of water and will potentially affect human health.
Collapse
Affiliation(s)
- Xin Luo
- Department of Earth Sciences, The University of Hong Kong, PR China; The University of Hong Kong, Shenzhen Research Institute (SRI), Shenzhen, PR China; The University of Hong Kong-Zhejiang Institute of Research and Innovation (HKU-ZIRI), Hangzhou, PR China
| | - Jiu Jimmy Jiao
- Department of Earth Sciences, The University of Hong Kong, PR China; The University of Hong Kong, Shenzhen Research Institute (SRI), Shenzhen, PR China; The University of Hong Kong-Zhejiang Institute of Research and Innovation (HKU-ZIRI), Hangzhou, PR China.
| | - Willard S Moore
- Department of Earth and Ocean Sciences, University of South Carolina, Columbia, 29208, SC, USA
| | - John A Cherry
- School of Engineering, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Ya Wang
- School of Earth Science and Geological Engineering, Sun Yat-sen University Guangzhou, 510275, PR China
| | - Kun Liu
- China Institute of Geo-Environment Monitoring, China Geological Survey, PR China
| |
Collapse
|
31
|
Zhang Y, Li H, Wang X, Wang C, Xiao K, Qu W. Submarine groundwater discharge and chemical behavior of tracers in Laizhou Bay, China. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2018; 189:182-190. [PMID: 29679819 DOI: 10.1016/j.jenvrad.2018.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/24/2017] [Accepted: 04/03/2018] [Indexed: 06/08/2023]
Abstract
Naturally occurring radon (222Rn) and radium isotopes are widely used to trace water mixing and submarine groundwater discharge (SGD) in the coastal zones. However, their activities in groundwater are variable both spatially and temporally. Here, time series sampling of 222Rn and radium was conducted to investigate their behavior in intertidal groundwater of Laizhou Bay, China. The result shows that groundwater redox conditions have an important impact on the behavior of tracers. The activities of tracers will decrease under oxidizing conditions and increase under reducing conditions. Radon and radium mass balance models were used to evaluate the flushing time and SGD based on spatial surveys in Laizhou Bay. The flushing time is estimated to be 32.9-55.3 d with coupled models, which agrees well with the result of tidal prism model. The trace-derived SGD in the whole bay ranges from 6.1 × 108 to 9.0 × 108 m3/d and the re-circulated seawater (RSGD) ranges from 5.5 × 108 to 8.5 × 108 m3/d. The average SGD and RSGD fluxes are 22.8 and 21.1 times greater than the Yellow River discharge in April 2014, respectively. The study provides a better understanding of the dynamics of coastal groundwater and behavior of tracers in a well-studied bay system.
Collapse
Affiliation(s)
- Yan Zhang
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution and School of Water Resources and Environment, China University of Geosciences-Beijing, Beijing 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences-Beijing, Beijing 100083, China
| | - Hailong Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences-Beijing, Beijing 100083, China; School of Environmental Science and Engineering and Shenzhen Key Laboratory of Soil and Groundwater Pollution Control, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Xuejing Wang
- School of Environmental Science and Engineering and Shenzhen Key Laboratory of Soil and Groundwater Pollution Control, Southern University of Science and Technology, Shenzhen 518055, China
| | - Chaoyue Wang
- School of Water Resources & Environment, Hebei GEO University, Shijiazhuang 050031, China
| | - Kai Xiao
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution and School of Water Resources and Environment, China University of Geosciences-Beijing, Beijing 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences-Beijing, Beijing 100083, China
| | - Wenjing Qu
- MOE Key Laboratory of Groundwater Circulation and Environment Evolution and School of Water Resources and Environment, China University of Geosciences-Beijing, Beijing 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences-Beijing, Beijing 100083, China
| |
Collapse
|
32
|
Prakash R, Srinivasamoorthy K, Gopinath S, Saravanan K, Vinnarasi F, Ponnumani G, Chidambaram S, Anandhan P. Radon isotope assessment of submarine groundwater discharge (SGD) in Coleroon River Estuary, Tamil Nadu, India. J Radioanal Nucl Chem 2018. [DOI: 10.1007/s10967-018-5877-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
33
|
Luo X, Kwok KL, Liu Y, Jiao J. A Permanent Multilevel Monitoring and Sampling System in the Coastal Groundwater Mixing Zones. GROUND WATER 2017; 55:577-587. [PMID: 28297744 DOI: 10.1111/gwat.12510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/17/2017] [Accepted: 02/21/2017] [Indexed: 06/06/2023]
Abstract
To study the spatial and temporal variability of water dynamics and chemical reactions within the coastal groundwater mixing zones (CGMZs), high-resolution periodical and spatial groundwater sampling within CGMZs is needed. However, current samplers and sampling systems may require heavy driving machines to install. There is also possible contamination from the metal materials for current samplers and sampling systems. Here, a permanent multilevel sampling system is designed to sample coastal groundwater within CGMZs. This cost-effective system consists of metal-free materials and can be installed easily. The system is tested in Po Sam Pai and Tingkok, Tolo Harbor and Hong Kong. Major ions, nutrients, stable isotopes and radium and radon isotopes were analyzed and the data provided scientific information to study the fresh-saltwater interface fluctuations, and temporal variations and spatial heterogeneity of geochemical processes occurred within CGMZs. The reliable spatial and temporal data from the sampling system demonstrate that the system functions well and can provide scientific data for coastal aquifer studies.
Collapse
Affiliation(s)
- Xin Luo
- Department of Earth Sciences, The University of Hong Kong, Hong Kong, China
- Shenzhen Research Institute (SRI), The University of Hong Kong, Shenzhen, China
| | - King Lun Kwok
- Department of Earth Sciences, The University of Hong Kong, Hong Kong, China
- Shenzhen Research Institute (SRI), The University of Hong Kong, Shenzhen, China
| | - Yi Liu
- Department of Earth Sciences, The University of Hong Kong, Hong Kong, China
- Shenzhen Research Institute (SRI), The University of Hong Kong, Shenzhen, China
| | - Jimmy Jiao
- Shenzhen Research Institute (SRI), The University of Hong Kong, Shenzhen, China
| |
Collapse
|