Carbon dioxide and methane dynamics in a human-dominated lowland coastal river network (Shanghai, China)

Yu, Zhongjie; Wang, Dongqi; Li, Yangjie; Deng, Huanguang; Hu, Beibei; Ye, Mingwu; Zhou, Guiyao; Liu, Da; Chen, Zhenlou; Xu, Shiyuan

doi:10.1002/2017jg003798

Cited by 50 publications

(43 citation statements)

References 92 publications

(185 reference statements)

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“…In support of this, recent work at the molecular level has highlighted that not all aromatic DOM is resistant to degradation (Mostovaya et al 2017). Finally, positive relationships between aquatic CO 2 and NH 4 have been reported elsewhere (Schrier-Uijl et al 2011, Yu et al 2017. Dai et al (2008) hypothesize that higher concentrations of NH 4 stimulate nitrification, thus leading to consumption of dissolved O 2 , with resulting increases in CO 2 production (the authors suggest that by combining the two oxidation processes that constitute nitrification, one mole of NH 4 would yield 1.9 moles of free CO 2 ).…”

Section: Concentrations and Fluxes Of Comentioning

confidence: 78%

Greenhouse gas emissions from urban ponds are driven by nutrient status and hydrology

et al. 2019

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Inland waters emit significant quantities of greenhouse gases (GHGs) such as methane (CH4) and carbon dioxide (CO2) to the atmosphere. On a global scale, these emissions are large enough that their contribution to climate change is now recognized by the Intergovernmental Panel on Climate Change. Much of the past focus on GHG emissions from inland waters has focused on lakes, reservoirs, and rivers, and the role of small, artificial waterbodies such as ponds has been overlooked. To investigate the spatial variation in GHG fluxes from artificial ponds, we conducted a synoptic survey of forty urban ponds in a Swedish city. We measured dissolved concentrations of CH4 and CO2, and made complementary measurements of water chemistry. We found that CH4 concentrations were greatest in high‐nutrient ponds (measured as total phosphorus and total organic carbon). For CO2, higher concentrations were associated with silicon and calcium, suggesting that groundwater inputs lead to elevated CO2. When converted to diffusive GHG fluxes, mean emissions were 30.3 mg CH4·m−2·d−1 and 752 mg CO2·m−2·d−1. Although these fluxes are moderately high on an areal basis, upscaling them to all Swedish urban ponds gives an emission of 8336 t CO2eq/yr (±1689) equivalent to 0.1% of Swedish agricultural GHG emissions. Artificial ponds could be important GHG sources in countries with larger proportions of urban land.

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Section: Concentrations and Fluxes Of Comentioning

confidence: 78%

Greenhouse gas emissions from urban ponds are driven by nutrient status and hydrology

et al. 2019

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“…Information available on individual urban water bodies suggests that the drivers behind CH 4 emissions are similar to those in rural, forest, and other natural areas (Martinez‐Cruz et al, ; Yu et al, ). All else being equal, shallow waters, which are typical of urban areas (McEnroe, Williams, Xenopoulos, Porcal, & Frost, ), are likely to emit more CH 4 per surface area, because the travel times of CH 4 bubbles generated by ebullition events and rising from the sediment to the water surface are likely to be shorter, limiting CH 4 oxidation by methanotrophy in the oxic water column (Bastviken, Cole, Pace, & Tranvik, ; Holgerson, ).…”

Section: Introductionmentioning

confidence: 99%

Methane emissions from contrasting urban freshwaters: Rates, drivers, and a whole‐city footprint

Ortega

González‐Quijano

Casper

et al. 2019

Global Change Biology

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Global urbanization trends impose major alterations on surface waters. This includes impacts on ecosystem functioning that can involve feedbacks on climate through changes in rates of greenhouse gas emissions. The combination of high nutrient supply and shallow depth typical of urban freshwaters is particularly conducive to high rates of methane (CH4) production and emission, suggesting a potentially important role in the global CH4 cycle. However, there is a lack of comprehensive flux data from diverse urban water bodies, of information on the underlying drivers, and of estimates for whole cities. Based on measurements over four seasons in a total of 32 water bodies in the city of Berlin, Germany, we calculate the total CH4 emission from various types of surface waters of a large city in temperate climate at 2.6 ± 1.7 Gg CH4/year. The average total emission was 219 ± 490 mg CH4 m−2 day−1. Water chemical variables were surprisingly poor predictors of total CH4 emissions, and proxies of productivity and oxygen conditions had low explanatory power as well, suggesting a complex combination of factors governing CH4 fluxes from urban surface waters. However, small water bodies (area <1 ha) typically located in urban green spaces were identified as emission hotspots. These results help constrain assessments of CH4 emissions from freshwaters in the world's growing cities, facilitating extrapolation of urban emissions to large areas, including at the global scale.

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“…Temperature dependency of methanogenesis affects CH 4 production in streams (Duc et al, 2010;Sieczko et al, 2016). However, the relationship between water temperature and CH 4 concentrations or fluxes in streams is not consistent among studies (Campeau & Giorgio, 2014;Dinsmore et al, 2013;Sieczko et al, 2016;Wallin et al, 2014;Yu et al, 2017). Moreover, dissolved organic carbon (DOC) concentrations can be positively correlated to CH 4 because high availability of organic carbon drives microbial metabolism resulting in high methane production (Christensen et al, 2003;Romeijn et al, 2019;Stanley et al, 2016;Throckmorton et al, 2015;Wik et al, 2016).…”

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confidence: 99%

Temporal Patterns of Methane Emissions From Two Streams With Different Riparian Connectivity

Leng

Kamjunke

et al. 2021

JGR Biogeosciences

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Streams are conduits and active processors of substances, linking different landscapes in the Earth's surface environment (Battin et al., 2008). Though streams only contribute a small part of the global surface area (0.3%-0.56% of the total land surface [Downing et al., 2012]), they are hot spots of biogeochemical cycling and greenhouse gas emissions. Although streams are typically oxic in the water column, recent evidence shows that streams and rivers can be responsible for as much as 50% of the CH 4 emitted from freshwaters (Stanley et al., 2016). However, assessment of the role of streams in the global CH 4 balance is hampered by a lack of data-especially long-term data. There is still a large uncertainty in CH 4 fluxes and the predicted Abstract Streams are regionally important sources of CH 4 to the atmosphere, but the temporal variability in and control on CH 4 concentrations and emissions are not well understood. Especially, lack of long-term data hampers our ability to predict CH 4 emissions from streams. Here, we present a 7-year data set of biweekly CH 4 concentration and underlying potential drivers from two adjacent small German streams with contrasting riparian area characteristics. Over the 7-year study period, mean CH 4 concentration and emissions were 0.20 and 0.07 μmol L −1 and 2.01 and 0.84 mmol m −2 d −1 for the two streams, respectively. Our findings suggest that the combination of seasonality and topography ultimately shaped the considerable temporal variations of CH 4 . CH 4 oxidation and production in the streams were probably of minor importance. Instead, fluctuations in CH 4 concentrations likely reflected a temporal pattern of CH 4 input from soils of the riparian zone with larger CH 4 variations in the stream with more riparian lands. Structural equation modeling revealed dissolved organic carbon and nitrate as important predictors of CH 4 concentration. However, we did not identify predictors of the considerable short-term variability, nor the explicit pathways of CH 4 delivery to streams. The discrepancy of the CH 4 flux between streams was likely triggered by different connectivities to riparian soils with higher CH 4 emissions in the hydrologically more connected stream. Interannual comparison showed that changing hydrologic conditions, rather than warming, may impact future CH 4 emissions from temperate streams. We predict that higher CH 4 emissions occur in wetter years in streams with close connectivity to riparian soils.Plain Language Summary Streams are increasingly recognized as an important source of methane (CH 4 ) to the atmosphere. However, emissions are extremely variable because the CH 4 concentration in streams changes a lot with time. We analyzed a long-term time series of CH 4 concentrations in two small German streams to understand the mechanisms behind these temporal fluctuations. Our two streams were always supersaturated in CH 4 and thus, emitted CH 4 to the atmosphere. A large part of the temporal variability can be explained by seasonal changes of discharge and ...

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Carbon dioxide and methane dynamics in a human-dominated lowland coastal river network (Shanghai, China)

Cited by 50 publications

References 92 publications

Greenhouse gas emissions from urban ponds are driven by nutrient status and hydrology

Greenhouse gas emissions from urban ponds are driven by nutrient status and hydrology

Methane emissions from contrasting urban freshwaters: Rates, drivers, and a whole‐city footprint

Temporal Patterns of Methane Emissions From Two Streams With Different Riparian Connectivity

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