Anthropogenic effects on greenhouse gas (CH4 and N2O) emissions in the Guadalete River Estuary (SW Spain)

Burgos, Macarena; Sierra, A.; Ortega, T.; Forja, Jesús M.

doi:10.1016/j.scitotenv.2014.06.038

Cited by 85 publications

(46 citation statements)

References 52 publications

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Section: Spatial Variations In Three Ghgs Observed Along the Middle Rmentioning

confidence: 99%

“…Direct influences of wastewater-derived GHGs have been observed in urban rivers receiving WWTP effluents (Garnier et al, 2013;Yu et al, 2013;Burgos et al, 2015;Alshboul et al, 2016;Wang et al, 2017a;Yoon et al, 2017). For example, large pulses of CH 4 and N 2 O in the Guadalete River estuary in Spain were found 350 near the discharge from a WWTP, as a combined result of direct gas emissions from WWTP effluents and indirect effects on the production of CH 4 and N 2 O in water channel and benthic sediments downstream (Burgos et al, 2015). Previously we used a mass balance approach based on three cruise underway measurements of pCO 2 to show that two tributaries JN and TC delivering WWTP effluents accounted for 72% of the CO 2 concentration measured at a downstream location in the lower Han outgassing along the downstream reach suggested that in June 2016 CO 2 produced from biodegradation was much greater than CO 2 consumed by phytoplankton and similar to the amount of CO 2 outgassed, while the bulk of CO 2 delivered by the tributaries was consumed by planktonic photosynthesis along the same reach in May 2015, when Chl a concentrations were much higher than in June 2016 .…”

Section: Spatial Variations In Three Ghgs Observed Along the Middle Rmentioning

confidence: 99%

“…Measurements of multiple GHGs in highly human-impacted river systems have provided drastically different pictures of the longitudinal and seasonal patterns of GHGs from those observed in large natural rivers (Silvennoinen et al, 2008;Burgos et al, 2015;Crawford et al, 2016;Smith et al, 2017;Wang et al, 2017b). A growing number of dams constructed on rivers worldwide have altered riverine flows of water and materials to the oceans, trapping over 100 billion metric tons of sediment and up to 3 billion metric tons of C in the reservoirs constructed over the last five decades (Syvitski et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…While enhanced primary production and anaerobic metabolism may play a determining role in long-term changes 80 in CO 2 and CH 4 emissions from the water column and sediments in impounded reaches, external inputs of organic matter and nutrients have also been suggested as a primary control on GHG emissions from urban streams and rivers (Alshboul et al, 2016;Smith et al, 2017;Wang et al, 2017b). Longitudinal surveys conducted along urbanized rivers have observed large pulsatile increases in CO 2 and other GHGs in rivers receiving the effluents from wastewater treatment plants (WWTPs) (Garnier et al, 2013;Burgos et al, 2015;Alshboul et al, 2016;Yoon et al, 2017). WWTP effluents and other anthropogenic 85 sources can not only exert direct effects on riverine GHG dynamics via discharged loads of GHGs, DOC, and nutrients but also modify riverine metabolic regimes (Garnier and Billen, 2007;Park et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Longitudinal discontinuities in riverine greenhouse gas dynamics generated by dams and urban wastewater

Jin¹,

Yoon²,

Begum³

et al. 2018

Preprint

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Abstract.Riverine emissions of CO 2 and other greenhouse gases (GHGs) represent crucial, but poorly constrained components of the global GHG budgets. Three major GHGs -CO 2 , CH 4 , and N 2 O -have rarely been measured simultaneously in river systems modified by human activities, adding uncertainties to the estimates of global riverine GHG emissions. Measurements of C isotopes in dissolved organic carbon (DOC), CO 2 , and CH 4 were combined with basin-wide surveys of three GHGs in the Han 15 River, South Korea to investigate the effects of dams and urban water pollution as primary controls on GHG dynamics in the highly human-impacted river basin with a population >25 million. Monthly monitoring and two-season comparison were conducted at 6 and 15 sites, respectively, to measure surface water concentrations of three GHGs, along with DOC and its optical properties. The basin-wide surveys were complemented with a boat cruise along the lower reach and synoptic samplings along a polluted tributary delivering effluents from a large wastewater treatment plant (WWTP) to the lower reach. The basin-20 wide surveys of three GHGs revealed distinct increases in the concentrations of three gases along the lower reach receiving urban tributaries enriched in GHGs and DOC. Compared to the spatial patterns of GHGs observed in the upper and lower reaches, the levels of pCO 2 were consistently lower across the impounded middle reach, whereas concentrations of CH 4 and N 2 O were relatively high in some impoundment-affected sites. Similar levels and temporal variations in three GHGs at the WWTP effluents and the receiving tributary indicated a disproportionate contribution of the WWTP to the tributary exports of 25 DOC and GHGs. Measurements of δ 13 C in surface water CO 2 and CH 4 sampled during the cruise along the lower reach, combined with δ 13 C and Δ 14 C in dissolved organic matter (DOM) sampled across the basin, implied that longitudinal decreases in Δ 14 C in DOM mighte be associated with wastewater-derived, old DOM in urban tributaries, which, together with enhanced photosynthesis and CH 4 oxidation in the eutrophic lower reach, appear to constrain downstream changes in δ 13 C in CO 2 and CH 4 . The overall results suggest that dams and urban wastewater may create longitudinal discontinuities in riverine metabolic 30 processes leading to large spatial variations in three GHGs. Further research is required to evaluate the relative contributions Biogeosciences Discuss., https://doi

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Section: Spatial Variations In Three Ghgs Observed Along the Middle Rmentioning

confidence: 99%

Section: Spatial Variations In Three Ghgs Observed Along the Middle Rmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Longitudinal discontinuities in riverine greenhouse gas dynamics generated by dams and urban wastewater

Jin¹,

Yoon²,

Begum³

et al. 2018

Preprint

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“…AOM coupled to sulfate reduction is a major contributor to the methane oxidation in oceanic systems (1), and the process of AOM coupled to nitrite reduction is a vital sink of methane in freshwater systems (11,39). However, the contribution of AOM to their transitional zonecoastal ecosystems remains obscure, although several researchers have noted the importance of methane oxidation in coastal ecosystems (40,41). Moreover, dissolved methane concentrations are dominantly submicromolar in coastal sediments but nanomolar in the water column, which indicates that the methane produced in anoxic underlying sediments was effectively oxidized when transported upward to the water/sediment interfaces (41).…”

Section: Figmentioning

confidence: 99%

Anaerobic Oxidation of Methane Coupled to Nitrite Reduction by Halophilic Marine NC10 Bacteria

Geng

Cai

et al. 2015

Appl Environ Microbiol

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Anaerobic oxidation of methane (AOM) coupled to nitrite reduction is a novel AOM process that is mediated by denitrifying methanotrophs. To date, enrichments of these denitrifying methanotrophs have been confined to freshwater systems; however, the recent findings of 16S rRNA and pmoA gene sequences in marine sediments suggest a possible occurrence of AOM coupled to nitrite reduction in marine systems. In this research, a marine denitrifying methanotrophic culture was obtained after 20 months of enrichment. Activity testing and quantitative PCR (qPCR) analysis were then conducted and showed that the methane oxidation activity and the number of NC10 bacteria increased correlatively during the enrichment period. 16S rRNA gene sequencing indicated that only bacteria in group A of the NC10 phylum were enriched and responsible for the resulting methane oxidation activity, although a diverse community of NC10 bacteria was harbored in the inoculum. Fluorescence in situ hybridization showed that NC10 bacteria were dominant in the enrichment culture after 20 months. The effect of salinity on the marine denitrifying methanotrophic culture was investigated, and the apparent optimal salinity was 20.5‰, which suggested that halophilic bacterial AOM coupled to nitrite reduction was obtained. Moreover, the apparent substrate affinity coefficients of the halophilic denitrifying methanotrophs were determined to be 9.8 ؎ 2.2 M for methane and 8.7 ؎ 1.5 M for nitrite.A naerobic oxidation of methane (AOM) occurs extensively in natural ecosystems and is a crucial biological sink in the global methane cycle that maintains the balance of greenhouse gas content in the atmosphere (1). To date, five electron acceptors that support AOM, including AOM coupled to sulfate reduction (2), nitrite reduction (3), nitrate reduction (4), iron reduction (5), and manganese reduction (5), have been discovered in natural settings. Moreover, on the basis of bioenergetic calculations, researchers have speculated that several other types of AOM (e.g., AOM coupled to perchlorate reduction, arsenate reduction, and selenate reduction) may exist in nature (6); however, these possible types have not yet been confirmed. In particular, AOM coupled to nitrite reduction has been a predominant research focus in the past several years. AOM coupled to nitrite reduction was also called nitrite-dependent anaerobic methane oxidation (ndamo) in previous reports. It has been demonstrated that AOM coupled to nitrite reduction is mediated by the bacterium "Candidatus Methylomirabilis oxyfera" (denitrifying methanotroph) (7), which is affiliated with the candidate NC10 phylum (8). This candidate division (NC10 phylum) was first defined by classification of environmental sequences retrieved from aquatic microbial formations in flooded caves (9). To date, our knowledge regarding the NC10 phylum has stemmed largely from research into "Ca. Methylomirabilis oxyfera" and "Ca. Methylomirabilis oxyfera"-like bacteria. According to the phylogenetic affiliations of 16S rRNA gene sequ...

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Spatio‐temporal variability of methane (CH₄) concentrations and diffusive fluxes from a tropical coastal embayment surrounded by a large urban area (Guanabara Bay, Rio de Janeiro, Brazil)

Cotovicz

Knoppers

Brandini

et al. 2016

Limnology & Oceanography

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The increasing concentrations of methane (CH 4 ) in the atmosphere stress the importance of monitoring and quantifying the fluxes from coastal environments. In nine sampling campaigns between 2013 and 2014, we measured the spatial CH 4 concentrations, identified major sources and calculated the fluxes at the airwater interface in an eutrophic tropical embayment, Guanabara Bay, Rio de Janeiro, Brazil. The bay presented high spatial variability of CH 4 concentrations, without a significant trend with salinity, but observed the influence of the urban areas at its watershed. Although the more polluted sector of the bay accounts for about 10% of the sampled surface area, it contributed to one half of the bay's total CH 4 emissions. In most cases, high CH 4 concentrations seemed be sustained by allochtonous sources such as the sewage network and polluted rivers, especially under high accumulated precipitation conditions. In the most stratified area, at the inner and centre of the Bay, CH 4 concentrations were not significantly higher in bottom hypoxic waters than in surface waters, suggesting that CH 4 diffusion from these sediments was modest, due to the prevalence of sulphate reduction over methanogenesis. Our calculated annual air-sea fluxes (565-980 lmol m 22 d 21 ) are well above those of most estuaries worldwide, showing that urban pollution can be an important source of CH 4 to the coastal waters and even more significant than the presence of organic-rich environments, like salt marshes and mangroves. Comparing the greenhouse gas emissions in terms of CO 2 -equivalent, CH 4 emissions reduced the net CO 2 sink in Guanabara Bay by 16%.

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Anthropogenic effects on greenhouse gas (CH4 and N2O) emissions in the Guadalete River Estuary (SW Spain)

Cited by 85 publications

References 52 publications

Longitudinal discontinuities in riverine greenhouse gas dynamics generated by dams and urban wastewater

Longitudinal discontinuities in riverine greenhouse gas dynamics generated by dams and urban wastewater

Anaerobic Oxidation of Methane Coupled to Nitrite Reduction by Halophilic Marine NC10 Bacteria

Spatio‐temporal variability of methane (CH₄) concentrations and diffusive fluxes from a tropical coastal embayment surrounded by a large urban area (Guanabara Bay, Rio de Janeiro, Brazil)

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Anthropogenic effects on greenhouse gas (CH4 and N2O) emissions in the Guadalete River Estuary (SW Spain)

Cited by 85 publications

References 52 publications

Longitudinal discontinuities in riverine greenhouse gas dynamics generated by dams and urban wastewater

Longitudinal discontinuities in riverine greenhouse gas dynamics generated by dams and urban wastewater

Anaerobic Oxidation of Methane Coupled to Nitrite Reduction by Halophilic Marine NC10 Bacteria

Spatio‐temporal variability of methane (CH4) concentrations and diffusive fluxes from a tropical coastal embayment surrounded by a large urban area (Guanabara Bay, Rio de Janeiro, Brazil)

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Spatio‐temporal variability of methane (CH₄) concentrations and diffusive fluxes from a tropical coastal embayment surrounded by a large urban area (Guanabara Bay, Rio de Janeiro, Brazil)