Sedimentary processes dominate nitrous oxide production and emission in the hypoxic zone off the Changjiang River estuary

Yang, Jinqiu; Hsu, Ting-Chang; Tan, Ehui; Lee, Kitack; Krom, Michael D.; Kang, Sijing; Dai, Minhan; Hsiao, Shih-Hsin; Yan, Xiuli; Zou, Wenbin; Tian, Li; Kao, Shuh‐Ji

doi:10.1016/j.scitotenv.2022.154042

Cited by 19 publications

(15 citation statements)

References 60 publications

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“…Results from this study indicate that the biogeochemical feedbacks between WLIS water column and benthic processes are tightly linked to hypoxia. Benthic nitrification and denitrification are primary drivers of sediment nitrous oxide (N 2 O) production (Meyer et al 2008 ; Barnes and Upstill-Goddard 2018 ; Foster and Fulweiler 2019 ; Yang et al 2022 ), but sediment releases of the potent greenhouse gases N 2 O and methane (CH 4 ) are controlled by OM availability (Mazur et al 2021 ), specifically anoxic sediments during high OM loading that accelerate C remineralization via methanogenesis (Gelesh et al 2016 ). LIS sediments are a source of N 2 O (8.63 + 3.18 nmol m −2 h −1 ) and CH 4 (23.80 + 18.05 nmol m −2 h −1 ; Mazur et al 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Transitions in nitrogen and organic matter form and concentration correspond to bacterial population dynamics in a hypoxic urban estuary

et al. 2023

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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 × 10 4 –1.1 × 10 5 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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Section: Discussionmentioning

confidence: 99%

Transitions in nitrogen and organic matter form and concentration correspond to bacterial population dynamics in a hypoxic urban estuary

et al. 2023

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“…The δ value is reported conventionally as the permil (‰) deviation relative to atmospheric N 2 and Vienna Standard Mean Ocean Water (VSMOW) for nitrogen and oxygen stable isotope ratios, respectively. 36 Sample analysis had an average precision of 15 N, 15 N α , δ 18 O, and SP of N 2 O of 0.1, 0.1, 0.4, and 0.5‰, respectively. The stable oxygen isotopic composition of the overlying water (δ 18 O-H 2 O) was measured using an isotopic water analyzer (LGR LWA-45EP, Los Gatos Research, US), and its measurement accuracy was 0.1‰.…”

Section: Analyses Of N 2 O Concentrations and Fluxesmentioning

confidence: 99%

“…Gas samples from three replications were introduced into the same evaluating airbag to determine the stable isotope and isotopocule values of N 2 O with an isotope ratio mass spectrometer interfaced with a trace gas system (GC-IRMS; Delta V Plus, Thermo Fisher Scientific, Bremen, Germany) in an environmentally stable isotope lab at the Chinese Academy of Agricultural Science. N 2 O isotopes, including δ 15 (1)…”

Section: Analyses Of N 2 O Concentrations and Fluxesmentioning

confidence: 99%

“…where 15 N is the average isotope ratio for 15 N/ 14 N, and 15 N α and 15 N β represent the 15 N/ 14 N ratios at the center and end sites of N 2 O molecules, respectively. The δ value is reported conventionally as the permil (‰) deviation relative to atmospheric N 2 and Vienna Standard Mean Ocean Water (VSMOW) for nitrogen and oxygen stable isotope ratios, respectively.…”

Section: Analyses Of N 2 O Concentrations and Fluxesmentioning

confidence: 99%

“…These analyses are far from able to point to the contributions of specific N 2 O production pathways and to differentiate the role of N 2 O reduction. To overcome these limitations, numerous studies have employed isotope labeling and inhibitor addition techniques to predict conclusive information on N 2 O production in laboratory incubations of water columns and sediments, − but these methods present obvious flaws, such as an incomplete diffusion of added tracers or inhibitors and unintended effects on microbial activities or other unconstrained bottle effects. − Furthermore, these methods cannot reflect in situ conditions or reflect field N 2 O production and emissions. ,− …”

Section: Introductionmentioning

confidence: 99%

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Tracing Microbial Production and Consumption Sources of N₂O in Rivers on the Qinghai-Tibet Plateau via Isotopocule and Functional Microbe Analyses

Chen

Zhang

Liu

et al. 2023

Environ. Sci. Technol.

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Nitrous oxide (N 2 O), a potent greenhouse gas, is produced in rivers through a series of microbial metabolic pathways. However, the microbial source of N 2 O production and the degree of N 2 O reduction in river systems are not well understood and quantified. This work investigated isotopic compositions (δ 15 N-N 2 O and δ 18 O-N 2 O) and N 2 O site preference as well as N 2 O-related microbial features, thereby differentiating the importance of nitrification, denitrification, and N 2 O reduction in controlling N 2 O emissions from five rivers on the eastern Qinghai-Tibet Plateau (EQTP). The average N 2 O 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 N 2 O. Canonical and nitrifier denitrification dominated riverine N 2 O production, with contribution being approximately 90%. Nitrification is a nonnegligible source of N 2 O production, and N 2 O concentration was positively correlated with nitrification genetic potential. The degree of N 2 O 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 N 2 O in rivers, and the intense microbial reduction of N 2 O significantly accounts for the low N 2 O emissions observed in EQTP rivers, suggesting that both the production and consumption of N 2 O in rivers should be considered in the future.

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Emission of nitrous oxide in tidal-influenced mangrove ecosystem of Indian Sundarban

Das,

Ray,

Pal

et al. 2024

Developments in Environmental Science

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Sedimentary processes dominate nitrous oxide production and emission in the hypoxic zone off the Changjiang River estuary

Cited by 19 publications

References 60 publications

Transitions in nitrogen and organic matter form and concentration correspond to bacterial population dynamics in a hypoxic urban estuary

Transitions in nitrogen and organic matter form and concentration correspond to bacterial population dynamics in a hypoxic urban estuary

Tracing Microbial Production and Consumption Sources of N₂O in Rivers on the Qinghai-Tibet Plateau via Isotopocule and Functional Microbe Analyses

Emission of nitrous oxide in tidal-influenced mangrove ecosystem of Indian Sundarban

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Sedimentary processes dominate nitrous oxide production and emission in the hypoxic zone off the Changjiang River estuary

Cited by 19 publications

References 60 publications

Transitions in nitrogen and organic matter form and concentration correspond to bacterial population dynamics in a hypoxic urban estuary

Transitions in nitrogen and organic matter form and concentration correspond to bacterial population dynamics in a hypoxic urban estuary

Tracing Microbial Production and Consumption Sources of N2O in Rivers on the Qinghai-Tibet Plateau via Isotopocule and Functional Microbe Analyses

Emission of nitrous oxide in tidal-influenced mangrove ecosystem of Indian Sundarban

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Tracing Microbial Production and Consumption Sources of N₂O in Rivers on the Qinghai-Tibet Plateau via Isotopocule and Functional Microbe Analyses