Methane and nitrous oxide concentrations and fluxes from heavily polluted urban streams: Comprehensive influence of pollution and restoration

Wang, Xiaofeng; Yu, Li; Liu, Tingting; He, Yixin; Wu, Shengnan; Chen, Huai; Wang, Jilong; Li, Xian‐Xiang; Li, Hang; Que, Ziyi; Qing, Zhaoyin; Zhou, Ting

doi:10.1016/j.envpol.2022.120098

Cited by 24 publications

(12 citation statements)

References 120 publications

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“…The much lower dCH 4 observed in autumn (Figure 4c) was contrary to previous studies [19,44,45]. The authors ascribed this seasonal pattern to the synthetic effect of temperature and organic carbon availability [19,45,46].…”

Section: Seasonal and Spatial Shifts Of Co2 And Ch4contrasting

confidence: 72%

The Influence of Seasonal Variability of Eutrophication Indicators on Carbon Dioxide and Methane Diffusive Emissions in the Largest Shallow Urban Lake in China

Ma,

Wang,

Jiang

et al. 2023

Water

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Eutrophication is prevalent in urban lakes; however, a knowledge gap exists regarding eutrophication influences on carbon dynamics in these ecosystems. In the present study, we investigated the carbon dioxide (CO2) and methane (CH4) concentration and diffusion fluxes in Lake Tangxun (the largest shallow Chinese urban lake) in the autumn and winter of 2022 and spring and summer of 2023. We found that Lake Tangxun served as a source of GHGs, with average emission rates of 5.52 ± 12.16 mmol CO2 m−2 d−1 and 0.83 ± 2.81 mmol CH4 m−2 d−1, respectively. The partial pressure of dissolved CO2 (pCO2) (averaging 1321.39 ± 1614.63 μatm) and dissolved CH4 (dCH4) (averaging 4.29 ± 13.71 μmol L−1) exceeded saturation levels. Seasonal variability was observed in the pCO2 and dCH4 as well as CH4 fluxes, while the CO2 flux remained constant. The mean pCO2 and dCH4, as well as carbon emissions, were generally higher in summer and spring. pCO2 and dCH4 levels were significantly related to total nitrogen (TN), total phosphorus (TP), and ammonium-nitrogen (N-NH4+), and N-NH4+ was a main influencing factor of pCO2 and dCH4 in urban eutrophic lakes. The positive relationships of pCO2, dCH4 and trophic state index highlighted that eutrophication could elevate CO2 and CH4 emissions from the lake. This study highlights the fact that eutrophication can significantly increase carbon emissions in shallow urban lakes and that urban lakes are substantial contributors to the global carbon budget.

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Section: Seasonal and Spatial Shifts Of Co2 And Ch4contrasting

confidence: 72%

The Influence of Seasonal Variability of Eutrophication Indicators on Carbon Dioxide and Methane Diffusive Emissions in the Largest Shallow Urban Lake in China

Ma,

Wang,

Jiang

et al. 2023

Water

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“…This indicates that comprehensive improvement in urban watersheds might weaken CO 2 emission potential via nutrient removal (especially N and P). Previous reports suggested that some restoration measures for nutrient removal could cause different nutrient restrictions and microbial abundance decreases (Chen et al., 2020; Smith & Kaushal, 2015), weakening in‐channel respiration and carbon emission (X. Wang et al., 2022). Nutrient removal (especially N and P) in heavily polluted rivers could be an effective measure for carbon emission reduction (Lammers & Bledsoe, 2017; X. Wang et al., 2017).…”

Section: Discussionmentioning

confidence: 99%

“…In this study, a classical headspace equilibrium method was employed to measure the direct CO 2 concentration ( p CO 2‐HE ) in the surface water. This method has been widely used for the determination of CO 2 and CH 4 concentrations in polluted urban waters (Begum et al., 2021; X. Wang et al., 2022) and some human‐disturbed rivers with high OC (Yu et al., 2017). The specific operations were as follows: 80 mL of high‐purity nitrogen (N 2 ) was injected into an aluminum‐lined gas bag filled with a 100 mL water sample to produce a headspace.…”

Section: Methodsmentioning

confidence: 99%

“…In this study, a classical headspace equilibrium method was employed to measure the direct CO 2 concentration (pCO 2-HE ) in the surface water. This method has been widely used for the determination of CO 2 and CH 4 concentrations in polluted urban waters (Begum et al, 2021;X. Wang et al, 2022) and some human-disturbed rivers with high OC (Yu et al, 2017).…”

Section: Pco 2 Measurementmentioning

confidence: 99%

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Ecological Restoration Effectively Mitigated pCO₂ and CO₂ Evasions From Severely Polluted Urban Rivers

Wang,

Liu

et al. 2023

JGR Biogeosciences

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Urban rivers are significant hotspots of CO2 emissions into the atmosphere, playing important roles in global carbon emission inventories. However, little is known about the effect of ecological restoration on CO2 dynamics in severely polluted urban rivers, and this strongly hindering our understanding of the positive effects of human activities on CO2 emissions in urbanized aquatic ecosystems. We measured CO2 partial pressure (pCO2) and fluxes in nine severely polluted urban rivers with varying degrees of ecological restoration, and assessed the relationships with water physicochemical parameters, pollution levels and basin environmental investment. Our results indicate that urban rivers with high pollution loadings were indeed hotspots of CO2 evasion. However, fully restored rivers had generally lower pCO2 and CO2 emissions than partially restored rivers and were observably lower than unrestored rivers, suggesting that watershed eco‐restoration could effectively reduce CO2 evasion. In particular, environmental investment per unit basin area had a significant negative correlation with CO2 evasion and could explain 51%–85% and 51% of total variability in pCO2 and CO2 fluxes among nine urban rivers respectively, emphasizing the potential benefits of carbon emission regulation resulting from positive environmental management. Nutrient removal and sewage interception during watershed eco‐restoration were key processes reducing pCO2 and CO2 fluxes in polluted urban rivers. pH alteration kept close correlations with pCO2 and acted as a sensitive regulator of CO2 evasion in the nine rivers. We highlight the importance of considering the coupling effects of pollution and restoration on the spatiotemporal variability of CO2 evasion and the uncertainty of related monitoring methods in urban watersheds.

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“…In addition to the natural land mentioned above, aquatic ecosystems, including reservoirs, streams, and rivers, are also important N 2 O sources [ 59 , 60 ]. The total N 2 O emissions from global rivers and streams account for 10%–15% of the total anthropogenic N 2 O emissions [ 61 ], and global riverine N 2 O emissions went through a growth of 91.5% from 235.7 Gg N 2 O yr −1 in 1961 to 455.7 Gg N 2 O yr −1 in 2016 [ 62 ]. N inputs into aquatic ecosystems include N leaching, N deposition, wastewater discharge, local N mineralization, etc., and aquatic N 2 O emissions are consistent with the geographic distribution of N use and population [ 60 , 63 ].…”

Section: Discussionmentioning

confidence: 99%

Four decades of full-scale nitrous oxide emission inventory in China

Liang,

Zhou,

Ren

et al. 2023

National Science Review

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China is among the top nitrous oxide (N2O)-emitting countries, but existing national inventories do not provide full-scale emissions including both natural and anthropogenic sources. We conducted a four-decade (1980–2020) of comprehensive quantification of Chinese N2O inventory using empirical emission factor method for anthropogenic sources and two up-to-date process-based models for natural sources. Total N2O emissions peaked at 2287.4 (1774.8–2799.9) Gg N2O yr−1 in 2018, and agriculture-developed regions, like the East, Northeast, and Central, were the top N2O-emitting regions. Agricultural N2O emissions have started to decrease after 2016 due to the decline of nitrogen fertilization applications, while, industrial and energetic sources have been dramatically increasing after 2005. N2O emissions from agriculture, industry, energy, and waste represented 49.3%, 26.4%, 17.5%, and 6.7% of the anthropogenic emissions in 2020, respectively, which revealed that it is imperative to prioritize N2O emission mitigation in agriculture, industry, and energy. Natural N2O sources, dominated by forests, have been steadily growing from 317.3 (290.3–344.1) Gg N2O yr−1 in 1980 to 376.2 (335.5–407.2) Gg N2O yr−1 in 2020. Our study produces a Full-scale Annual N2O dataset in China (FAN2020), providing emergent counting to refine the current national N2O inventories.

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Methane and nitrous oxide concentrations and fluxes from heavily polluted urban streams: Comprehensive influence of pollution and restoration

Cited by 24 publications

References 120 publications

The Influence of Seasonal Variability of Eutrophication Indicators on Carbon Dioxide and Methane Diffusive Emissions in the Largest Shallow Urban Lake in China

The Influence of Seasonal Variability of Eutrophication Indicators on Carbon Dioxide and Methane Diffusive Emissions in the Largest Shallow Urban Lake in China

Ecological Restoration Effectively Mitigated pCO₂ and CO₂ Evasions From Severely Polluted Urban Rivers

Four decades of full-scale nitrous oxide emission inventory in China

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Methane and nitrous oxide concentrations and fluxes from heavily polluted urban streams: Comprehensive influence of pollution and restoration

Cited by 24 publications

References 120 publications

The Influence of Seasonal Variability of Eutrophication Indicators on Carbon Dioxide and Methane Diffusive Emissions in the Largest Shallow Urban Lake in China

The Influence of Seasonal Variability of Eutrophication Indicators on Carbon Dioxide and Methane Diffusive Emissions in the Largest Shallow Urban Lake in China

Ecological Restoration Effectively Mitigated pCO2 and CO2 Evasions From Severely Polluted Urban Rivers

Four decades of full-scale nitrous oxide emission inventory in China

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Product

Resources

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Ecological Restoration Effectively Mitigated pCO₂ and CO₂ Evasions From Severely Polluted Urban Rivers