1
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Zheng Y, Zhan L, Ji Q, Ma X. Seasonal isotopic and isotopomeric signatures of nitrous oxide produced microbially in a eutrophic estuary. MARINE POLLUTION BULLETIN 2024; 204:116528. [PMID: 38833950 DOI: 10.1016/j.marpolbul.2024.116528] [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: 04/24/2024] [Revised: 05/27/2024] [Accepted: 05/27/2024] [Indexed: 06/06/2024]
Abstract
Anthropogenic input of excess nutrients stimulates massive nitrous oxide (N2O) production in estuaries with distinct seasonal variations. Here, nitrogen isotopic and isotopomeric signatures were utilized to investigate the seasonal dynamics of N2O production and nitrification at the middle reach of the eutrophic Pearl River Estuary in the south of China. Elevated N2O production primarily via ammonia oxidation (> 1 nM-N d-1) occurred from April to November, along with increased temperature and decreased dissolved oxygen concentration. This consistently oxygenated water column showed active denitrification, contributing 20-40 % to N2O production. The water column microbial N2O production generally constituted a minor fraction (10-15 %) of the estuarine water-air interface efflux, suggesting that upstream transport and tidal dilution regulated the dissolved N2O inventory in the middle reach of the estuary. Nitrification (up to 3000 nM-N d-1) played a critical role in bioavailable nitrogen conversion and N2O production, albeit with N2O yields below 0.05 %.
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Affiliation(s)
- Yijie Zheng
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, China
| | - Liyang Zhan
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Qixing Ji
- Earth, Ocean and Atmospheric Sciences Thrust, the Hong Kong University of Science and Technology (Guangzhou), Guangzhou, China.
| | - Xiao Ma
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai, China.
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2
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Jiang C, Wu J, Ye J, Hong Y. High throughput amplicon analysis reveals potential novel ammonia oxidizing prokaryotes in the eutrophic Jiaozhou Bay. MARINE POLLUTION BULLETIN 2024; 200:116046. [PMID: 38246016 DOI: 10.1016/j.marpolbul.2024.116046] [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: 10/16/2023] [Revised: 12/07/2023] [Accepted: 01/11/2024] [Indexed: 01/23/2024]
Abstract
Ammonia-oxidizing prokaryotes (AOPs) are the major contributors of ammonia oxidization with widely distribution. Here we investigated the phylogenetic diversity, community composition, and regulating factors of AOPs in Jiaozhou Bay (JZB) with high-throughput sequencing of amoA gene. Phylogenetic analysis showed most of the OTUs could not be clustered with any known AOPs, indicating there might exist putative novel AOPs. With new developed protocols for AOP community analysis, we confirmed that only 3 OTUs of ammonia-oxidizing archaea (AOA) could be affiliated to known Nitrosopumilaceae and Nitrososphaera, and the other OTUs were identified as novel AOA based on the threshold. All abstained OTUs of ammonia-oxidizing bacteria (AOB) were identified as novel clusters based on the threshold. Further analysis showed the novel AOPs had different distribution characteristics related to environmental factors. The high abundance and widespread distribution of these novel AOPs indicated that they played an important role in ammonia conversion in eutrophic JZB.
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Affiliation(s)
- Cuihong Jiang
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China
| | - Jiapeng Wu
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China.
| | - Jiaqi Ye
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China
| | - Yiguo Hong
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China.
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3
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Liu S, Gao Q, Wu J, Xie Y, Yang Q, Wang R, Cui Y. The concentration of CH 4, N 2O and CO 2 in the Pearl River estuary increased significantly due to the sediment particle resuspension and the interaction of hypoxia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 911:168795. [PMID: 37996023 DOI: 10.1016/j.scitotenv.2023.168795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 11/02/2023] [Accepted: 11/20/2023] [Indexed: 11/25/2023]
Abstract
Hypoxia and sediment particle resuspension (SPR) alter the biogeochemical cycle of estuarine and coastal seas, which in turn affects the production and emission of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) greenhouse gases (GHGs) in estuaries. Despite the importance of CH4, N2O and CO2 in estuarine ecosystems, little is known about their magnitude and spatiotemporal variation under the combined influence of hypoxia and SPR. This study utilized continuous mooring observations to investigate the temporal and spatial variations of GHGs before and after hypoxia in the Pearl River Estuary (PRE). The results showed that the concentration of GHGs in the water column increased significantly following hypoxia as compared to its absence. The synergistic effect of SPR and hypoxia significantly enhances GHGs production and accumulation in bottom water. Anaerobic mineralization of organic matter (OM) in an environment with severely low dissolved oxygen (DO) is the primary determinant for increased CH4 concentration, while OM and CH4 oxidation are the main drivers for maintaining high CO2 concentration in subsurface water. Hypoxic development enhanced denitrification N2O production in the water column. The presence of SPR enhanced oxygen-consuming coupled hypoxia significantly stimulated the increase of CH4, N2O and CO2 concentrations in the water column. Hypoxic development results in an increased water-air GHGs flux, but this effect may be masked by runoff plumes with high GHGs concentrations in the regions near the river outlets. This study highlights that hypoxia leads to significant increases in anaerobic GHGs production and subsequent emissions from estuarine water columns.
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Affiliation(s)
- Shuangyuan Liu
- School of Geography and Planning, Sun Yat-sen University, Guangzhou 510006, China
| | - Quanzhou Gao
- School of Geography and Planning, Sun Yat-sen University, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519080, China.
| | - Jiaxue Wu
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519080, China; School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Yuting Xie
- School of Geography and Planning, Sun Yat-sen University, Guangzhou 510006, China
| | - Qianqian Yang
- School of Geography and Planning, Sun Yat-sen University, Guangzhou 510006, China
| | - Ruowen Wang
- School of Geography and Planning, Sun Yat-sen University, Guangzhou 510006, China
| | - Yongsheng Cui
- Guangdong Center for Marine Development Research, Guangzhou 510220, China
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4
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Li P, Wallace CD, McGarr JT, Moeini F, Dai Z, Soltanian MR. Investigating key drivers of N 2O emissions in heterogeneous riparian sediments: Reactive transport modeling and statistical analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:166930. [PMID: 37704143 DOI: 10.1016/j.scitotenv.2023.166930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/15/2023]
Abstract
Nitrous oxide (N2O) is a potent greenhouse gas that also contributes to ozone depletion. Recent studies have identified river corridors as significant sources of N2O emissions. Surface water-groundwater (hyporheic) interactions along river corridors induce flow and reactive nitrogen transport through riparian sediments, thereby generating N2O. Despite the prevalence of these processes, the controlling influence of physical and geochemical parameters on N2O emissions from coupled aerobic and anaerobic reactive transport processes in heterogeneous riparian sediments is not yet fully understood. This study presents an integrated framework that combines a flow and multi-component reactive transport model (RTM) with an uncertainty quantification and sensitivity analysis tool to determine which physical and geochemical parameters have the greatest impact on N2O emissions from riparian sediments. The framework involves the development of thousands of RTMs, followed by global sensitivity and responsive surface analyses. Results indicate that characterizing the denitrification reaction rate constant and permeability of intermediate-permeability sediments (e.g., sandy gravel) are crucial in describing coupled nitrification-denitrification reactions and the magnitude of N2O emissions. This study provides valuable insights into the factors that influence N2O emissions from riparian sediments and can help in developing strategies to control N2O emissions from river corridors.
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Affiliation(s)
- Pei Li
- Department of Geosciences, University of Cincinnati, Cincinnati, OH 45221, United States.
| | | | - Jeffrey T McGarr
- Department of Geosciences, University of Cincinnati, Cincinnati, OH 45221, United States
| | - Farzad Moeini
- Department of Geosciences, University of Cincinnati, Cincinnati, OH 45221, United States
| | - Zhenxue Dai
- College of Construction Engineering, Jilin University, Changchun, Jilin 130026, China
| | - Mohamad Reza Soltanian
- Department of Geosciences, University of Cincinnati, Cincinnati, OH 45221, United States; Department of Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, United States.
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5
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Jiang C, Zhang S, Wang J, Xia X. Nitrous Oxide (N 2O) Emissions Decrease Significantly under Stronger Light Irradiance in Riverine Water Columns with Suspended Particles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19749-19759. [PMID: 37945339 DOI: 10.1021/acs.est.3c05526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Nitrous oxide (N2O) emissions from riverine water columns with suspended particles are important for the global N2O budget. Although sunlight is known to influence the activity of nitrogen-cycling microorganisms, its specific influence on N2O emissions in river systems remains unknown. This study analyzed the influences of light irradiance on N2O emissions in simulated oxic water columns with 15N-labeling and biological molecular techniques. Our results showed that N2O emissions were inhibited by light in the ammonium system (only 15NH4+ was added) and significantly decreased with increasing light irradiance in the nitrate system (only 15NO3- was added), despite contrasting variations in N2 emissions between these two systems. Lower N2O emission rates in the nitrate system under higher light conditions resulted from higher promotion levels of N2O reduction than N2O production. Increased N2O reduction was correlated to higher organic carbon bioavailability caused by photodegradation and greater potential for complete denitrification. Lower N2O production and higher N2O reduction were responsible for the lower N2O emissions observed in the ammonium system under light conditions. Our findings highlight the importance of sunlight in regulating N2O dynamics in riverine water columns, which should be considered in developing large-scale models for N2O processing and emissions in rivers.
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Affiliation(s)
- Chenrun Jiang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
- Department of Urban Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
| | - Sibo Zhang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
| | - Junfeng Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Xinghui Xia
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
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6
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Wang Z, Liu K. Nutrients transport behavior in inlet river in the Yellow River Delta in winter. MARINE POLLUTION BULLETIN 2023; 197:115815. [PMID: 37984090 DOI: 10.1016/j.marpolbul.2023.115815] [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: 10/21/2023] [Revised: 11/12/2023] [Accepted: 11/15/2023] [Indexed: 11/22/2023]
Abstract
The nutrients such as dissolved inorganic nitrogen (DIN, NH4+-N, NO2--N, and NO3--N), dissolved inorganic phosphorus (DIP, PO43-) and dissolved SiO2 (DSi) funneled by the inlet river are the dominant factors to coastal eutrophication. This study investigated nutrient transport process in typical inlet rivers in the Yellow River Delta. The indicator of coastal eutrophication potential and concentration ratio between upstream and downstream stations were used to evaluate the influence of different sources to the nutrient risks. It showed that urban areas are the most important source of the nutrients in studied rivers. The harbor and mariculture would have greater risk because of their proximity close to the coastal area. Wetland was a vital conversion to eliminate the river nutrients, and the retention could reach 80 %. It is imperative to protect and construct wetlands to reduce the nutrient pollution in the inlet river.
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Affiliation(s)
- Zhaohua Wang
- First Institute of Oceanography, MNR, Qingdao 266061, China
| | - Kai Liu
- Dongying Marine Development Research Institute, Dongying 257091, China.
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7
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Hu Y, Wu J, Ye J, Liu X, Wang Y, Ye F, Hong Y. The imbalance between N 2O production and reduction by multi-microbial communities determines sedimentary N 2O emission potential in the Pearl River Estuary. MARINE ENVIRONMENTAL RESEARCH 2023; 190:106119. [PMID: 37535997 DOI: 10.1016/j.marenvres.2023.106119] [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: 05/22/2023] [Revised: 07/04/2023] [Accepted: 07/26/2023] [Indexed: 08/05/2023]
Abstract
Denitrification is the dominant process of nitrogen removal and nitrous oxide (N2O) emissions in estuarine ecosystems. However, little is known regarding the microbial mechanism of the production and reduction of N2O in estuaries. We investigated in situ dissolved N2O as well as potential N2O production rate (NPR), reduction rate (NRR), and emission rate (NER), and key functional genes related to N2O transformation of denitrification in the Pearl River Estuary. Higher N2O emission potential was found in the upstream and midstream regions with higher NPR and lower NRR values. In contrast, higher NRR values were detected in downstream. Notably, nirS and nirK type N2O producers dominated the upstream zone, whereas abundant N2O reducers, especially nosZ II type N2O reducers, were observed in downstream. Most importantly, the gene abundance ratio (Rnir/nosZ) was significantly correlated with the N2O emission potential (Re). Niche differentiation between N2O producers and N2O reducers from upstream to downstream affected N2O emission potential. This study highlights the N2O emission potential in estuarine sediments is determined by an imbalance between N2O production and the reduction of multi-bacterial communities.
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Affiliation(s)
- Yaohao Hu
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, PR China; State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, PR China
| | - Jiapeng Wu
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, PR China
| | - Jiaqi Ye
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, PR China
| | - Xiaohan Liu
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, PR China
| | - Yu Wang
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, PR China
| | - Fei Ye
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, PR China
| | - Yiguo Hong
- Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, PR China.
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8
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Chen X, Zhang S, Liu J, Wang J, Xin Y, Sun S, Xia X. Tracing Microbial Production and Consumption Sources of N 2O in Rivers on the Qinghai-Tibet Plateau via Isotopocule and Functional Microbe Analyses. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:7196-7205. [PMID: 37097256 DOI: 10.1021/acs.est.3c00950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Nitrous oxide (N2O), a potent greenhouse gas, is produced in rivers through a series of microbial metabolic pathways. However, the microbial source of N2O production and the degree of N2O reduction in river systems are not well understood and quantified. This work investigated isotopic compositions (δ15N-N2O and δ18O-N2O) and N2O site preference as well as N2O-related microbial features, thereby differentiating the importance of nitrification, denitrification, and N2O reduction in controlling N2O emissions from five rivers on the eastern Qinghai-Tibet Plateau (EQTP). The average N2O concentration in overlying water (15.2 nmol L-1) was close to that in porewater (17.5 nmol L-1), suggesting that both overlying water and sediment are potentially important sources of N2O. Canonical and nitrifier denitrification dominated riverine N2O production, with contribution being approximately 90%. Nitrification is a non-negligible source of N2O production, and N2O concentration was positively correlated with nitrification genetic potential. The degree of N2O reduction ranged from 78.1 to 94.1% (averaging 90%), significantly exceeding the reported values (averaging 70%) in other freshwaters, which was attributed to the higher ratios of organic carbon to nitrogen and lower ratio of (nirS + nirK)/nosZ in EQTP rivers. This study indicates that a combination of isotopic and isotopocule values with functional microbe analysis is useful for quantifying the microbial sources of N2O in rivers, and the intense microbial reduction of N2O significantly accounts for the low N2O emissions observed in EQTP rivers, suggesting that both the production and consumption of N2O in rivers should be considered in the future.
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Affiliation(s)
- Xin Chen
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Sibo Zhang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Jiao Liu
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Junfeng Wang
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Yuan Xin
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Siyue Sun
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Xinghui Xia
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
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9
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Humphries GE, Espinosa JI, Ambrosone M, Ayala ZR, Tzortziou M, Goes JI, Greenfield DI. Transitions in nitrogen and organic matter form and concentration correspond to bacterial population dynamics in a hypoxic urban estuary. BIOGEOCHEMISTRY 2023; 163:219-243. [PMID: 36968009 PMCID: PMC9959957 DOI: 10.1007/s10533-023-01021-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/18/2023] [Indexed: 06/18/2023]
Abstract
UNLABELLED Nitrogen (N) inputs to developed coastlines are linked with multiple ecosystem and socio-economic impacts worldwide such as algal blooms, habitat/resource deterioration, and hypoxia. This study investigated the microbial and biogeochemical processes associated with recurrent, seasonal bottom-water hypoxia in an urban estuary, western Long Island Sound (WLIS), that receives high N inputs. A 2-year (2020-2021) field study spanned two hypoxia events and entailed surface and bottom depth water sampling for dissolved nutrients as inorganic N (DIN; ammonia-N and nitrite + nitrate (N + N)), organic N, orthophosphate, organic carbon (DOC), as well as chlorophyll a and bacterial abundances. Physical water quality data were obtained from concurrent conductivity, temperature, and depth casts. Results showed that dissolved organic matter was highest at the most-hypoxic locations, DOC was negatively and significantly correlated with bottom-water dissolved oxygen (Pearson's r = -0.53, p = 0.05), and ammonia-N was the dominant DIN form pre-hypoxia before declining throughout hypoxia. N + N concentrations showed the reverse, being minimal pre-hypoxia then increasing during and following hypoxia, indicating that ammonia oxidation likely contributed to the switch in dominant DIN forms and is a key pathway in WLIS water column nitrification. Similarly, at the most hypoxic sampling site, bottom depth bacteria concentrations ranged ~ 1.8 × 104-1.1 × 105 cells ml-1 pre-hypoxia, declined throughout hypoxia, and were positively and significantly correlated (Pearson's r = 0.57; p = 0.03) with ammonia-N, confirming that hypoxia influences N-cycling within LIS. These findings provide novel insight to feedbacks between major biogeochemical (N and C) cycles and hypoxia in urban estuaries. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10533-023-01021-2.
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Affiliation(s)
- Georgie E. Humphries
- School of Earth and Environmental Sciences, Queens College, Queens, NY 11367 USA
- Advanced Science Research Center at the Graduate Center, New York, NY 10031 USA
| | - Jessica I. Espinosa
- Advanced Science Research Center at the Graduate Center, New York, NY 10031 USA
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269 USA
| | | | - Zabdiel Roldan Ayala
- School of Earth and Environmental Sciences, Queens College, Queens, NY 11367 USA
- Advanced Science Research Center at the Graduate Center, New York, NY 10031 USA
| | - Maria Tzortziou
- City College Center for Discovery and Innovation, New York, NY 10031 USA
- Department of Earth and Atmospheric Sciences, City College of New York, New York, USA
| | | | - Dianne I. Greenfield
- School of Earth and Environmental Sciences, Queens College, Queens, NY 11367 USA
- Advanced Science Research Center at the Graduate Center, New York, NY 10031 USA
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10
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Liu S, Gao Q, Wu J, Xie Y, Yang Q, Wang R, Zhang J, Liu Q. Spatial distribution and influencing mechanism of CO 2, N 2O and CH 4 in the Pearl River Estuary in summer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 846:157381. [PMID: 35850336 DOI: 10.1016/j.scitotenv.2022.157381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/05/2022] [Accepted: 07/11/2022] [Indexed: 06/15/2023]
Abstract
Estuaries, considered as the important carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) sources to the atmosphere, are increasingly affected by near-bottom hypoxia. However, the impact of estuarine hypoxic zone development on GHGs production and discharge remains poorly understood due to the seasonal and spatially distributed heterogeneity of estuarine hypoxia occurrence and the lack of simultaneous monitoring of the distribution of bottom hypoxic waters and the vertical distribution of GHGs. Here, we conducted high spatial resolution vertical stratification sampling and analysis of water column GHGs in the Pearl River Estuary (PRE), a large estuary with frequent hypoxia in recent years. Our results showed that Pearl River runoff is the main source of GHGs in the PRE. Strong nitrification is an important N2O production mechanism in the PRE. In situ generation of water and resuspension of surface sediments were the main sources of CH4 in bottom water, while massive organic matter (OM) mineralization is the main driver of CO2 in bottom water. The development of a hypoxic zone in the PRE significantly increased the concentration of N2O and CH4 in the bottom water and thus increased air-water fluxes. The air-water fluxes of N2O, CH4 and CO2 of PRE in summer were 31.9 ± 7.5 μmol m-2 d-1, 192.5 ± 229.4 μmol m-2 d-1 and 51.9 ± 14.1 mmol m-2 d-1, respectively. This study reveals that GHGs fluxes from estuarine waters to the atmosphere will increase significantly with increasing eutrophication caused by human activities and the expansion of hypoxic zones in estuarine waters.
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Affiliation(s)
- Shuangyuan Liu
- School of Geography and Planning, Sun Yat-sen University, Guangzhou 510006, China
| | - Quanzhou Gao
- School of Geography and Planning, Sun Yat-sen University, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519080, China.
| | - Jiaxue Wu
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519080, China; School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Yuting Xie
- School of Geography and Planning, Sun Yat-sen University, Guangzhou 510006, China
| | - Qianqian Yang
- School of Geography and Planning, Sun Yat-sen University, Guangzhou 510006, China
| | - Ruowen Wang
- School of Geography and Planning, Sun Yat-sen University, Guangzhou 510006, China
| | - Jing Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China; Faculty of Science, Academic Assembly, University of Toyama, Toyama 9300885, Japan
| | - Qian Liu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China
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11
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Tan E, Hsu TC, Zou W, Yan X, Huang Z, Chen B, Chang Y, Zheng Z, Zheng L, Xu M, Tian L, Kao SJ. Quantitatively deciphering the roles of sediment nitrogen removal in environmental and climatic feedbacks in two subtropical estuaries. WATER RESEARCH 2022; 224:119121. [PMID: 36126626 DOI: 10.1016/j.watres.2022.119121] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 09/11/2022] [Accepted: 09/13/2022] [Indexed: 06/15/2023]
Abstract
Sedimentary denitrification and anaerobic ammonium oxidation (anammox) are two microbially-mediated nitrogen removal pathways with distinct climatic feedbacks. Estuaries receive large fluxes of anthropogenic nitrogen and serve as hotspots for nitrogen loss. Applying 15N isotope pairing technique and sediment intact core incubation in two subtropical estuaries, the Yangtze River Estuary (YRE) and Jiulong River Estuary (JRE), we show that denitrification predominates the sedimentary nitrogen loss with a minor contribution (8.6 ± 7.5%) from anammox. Particulate organic matter degradation sustains the sedimentary nitrogen removal linking the nitrogen transformations between water column and sediment. Our results indicate that estuarine sediments exhibit high areal nitrogen removal rate, but play a relatively weak role in eliminating the nitrogen inputted from river basin due to the limited area. The riverine excess nitrogen will eventually enter into the adjacent continental shelf and be removed via phytoplankton assimilation-sedimentation-degradation-coupled nitrification-denitrification. In addition, sedimentary denitrification causes 1.8 ± 2.2% of nitrogen flow towards nitrous oxide (N2O) production and the derived N2O release flux accounts for 59% and 65% of the daily sea-air N2O emission in the YRE and JRE, respectively. These findings contribute to a better understanding of estuarine sedimentary nitrogen removal and associated climate feedbacks, and to the parameterization of Earth system models.
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Affiliation(s)
- Ehui Tan
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China.
| | - Ting-Chang Hsu
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Wenbin Zou
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Xiuli Yan
- Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, College of Science, Shantou University, Shantou, China
| | - Zhixiong Huang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan, China
| | - Bin Chen
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Yongkai Chang
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan, China
| | - Zhenzhen Zheng
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan, China
| | - Liwei Zheng
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan, China
| | - Min Xu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan, China
| | - Li Tian
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
| | - Shuh-Ji Kao
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, Hainan, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China.
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