Diffusive methane fluxes from Negro, Solimões and Madeira rivers and fringing lakes in the Amazon basin

Barbosa, Pedro M.; Mélack, John M.; Farjalla, Vinicius F.; Amaral, J. H.; Scofield, Vinicius; Forsberg, Bruce R.

doi:10.1002/lno.10358

Cited by 46 publications

(45 citation statements)

References 73 publications

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“…Data on Amazonian CH 4 concentrations are much sparser than p CO 2 , with large spatial and temporal variability of concentrations and associated fluxes (Melack et al ; Sawakuchi et al ; Borges et al ; Barbosa et al ). In contrast to the large spatially distributed measurements of previous studies such as Barbosa et al (), which measured CH 4 at four locations along a 700 km transect of the Negro River and in 21 tributaries within the Negro basin, this article presents smaller scale CH 4 measurements. Methane distribution was characterized by a few localized areas of distinctly higher concentrations in lakes, which are known emitters of CH 4 (Crill et al ; Devol et al ), and where the igarapé joins the black river at NA.…”

Section: Discussionmentioning

confidence: 99%

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Radon‐traced pore‐water as a potential source of CO₂ and CH₄ to receding black and clear water environments in the Amazon Basin

Call

Sanders

Enrich‐Prast

et al. 2018

Limnol Oceanogr Letters

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Groundwater is a primary source of dissolved CO2 and CH4 in Amazonian headwaters, yet in higher order rivers, a groundwater/pore‐water source is difficult to constrain due to the high spatial and temporal heterogeneity of pore‐water exchange. Here, we report coupled, high resolution measurements of pCO2, CH4, and 222Rn (a natural pore‐water and groundwater tracer) during receding waters in the three major water types of the Central Amazon Basin: black (Negro River); clear (Tapajós River); white (Madeira River). Considerable spatial heterogeneity was observed in pCO2, CH4, and 222Rn concentrations ranging from 460 μatm to 8030 μatm, 7 nM to 281 nM, and 713 dpm m−3 to 8516 dpm m−3, respectively. The significant correlations between pCO2 and CH4 to 222Rn in the black and clear waters suggests that pore‐water further enhanced CO2 supersaturation by 18–47% and is a driver of CH4 dynamics in these waters.

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Section: Discussionmentioning

confidence: 99%

“…The Amazon river system is generally supersaturated in CO 2 and CH 4 , and is estimated to emit globally significant amounts of both gases (Richey et al ; Melack et al ; Rasera et al ; Sawakuchi et al ; Barbosa et al ). The factors contributing to CO 2 supersaturation remain unclear and are likely spatially and temporally variable (Richey et al ).…”

mentioning

confidence: 99%

Radon‐traced pore‐water as a potential source of CO₂ and CH₄ to receding black and clear water environments in the Amazon Basin

Call

Sanders

Enrich‐Prast

et al. 2018

Limnol Oceanogr Letters

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“…Moreover, we only focused on CO 2 exchange, and CH 4 should not be ignored in Doñana aquatic habitats, as inland and coastal waters are known to be important sources of methane to the atmosphere [Barbosa et al, 2016;Borges et al, 2016;Chuang et al, 2017;Upstill-Goddard and Barnes, 2016;Panneer-Selvam et al, 2014]. CH 4 emissions could indeed turn this productive ecosystem into a net C source, as already shown in freshwater marshes [Chu et al, 2014] and in the Sacramento delta wetlands [McNicol et al, 2017].…”

Section: Discussionmentioning

confidence: 99%

Effect of hydroperiod on CO₂fluxes at the air-water interface in the Mediterranean coastal wetlands of Doñana

Huertas

Flecha

Figuerola

et al. 2017

J. Geophys. Res. Biogeosci.

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Wetlands are productive ecosystems that play an important role in the Earth's carbon cycle and thus global carbon budgets. Climate variability affects amount of material entering and the metabolic balance of wetlands, thereby modifying carbon dynamics. This study presents spatiotemporal changes in air‐water CO2 exchange in the vast wetlands of Doñana (Spain) in relation to different hydrological cycles. Water sources feeding Doñana, including groundwater and streams, ultimately depend on the fluctuating balance between annual precipitation and evapotranspiration. Hence, in order to examine the contribution of the rainfall pattern to the emission/capture of CO2 by a range of aquatic habitats in Doñana, we took monthly measurements during severely wet, dry, and normal hydrological years (2010–2013). During wet hydrological cycles, CO2 outgassing from flooded marshes markedly decreased in comparison to that observed during subsequent dry‐normal cycles, with mean values of 25.84 ± 19 and 5.2 ± 8 mmol m−2 d−1, respectively. Under drier meteorological conditions, air‐water CO2 fluxes also diminished in permanent floodplains and ponds, which even behaved as mild sinks for atmospheric CO2 during certain periods. Increased inputs of dissolved CO2 from the underground aquifer and the stream following periods of high rainfall are believed to be behind this pattern. Large lagoons with a managed water supply from an adjacent estuary took up atmospheric CO2 nearly permanently. Regional air‐water carbon transport was 15.2 GgC yr−1 under wet and 1.24 GgC yr−1 under dry meteorological conditions, well below the estimated net primary production for Doñana wetlands, indicating that the ecosystem acts as a large CO2 sink.

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“…The detection limit of our fluxes measurements was calculated as 0.22 mmol m −2 hr −1 of CO 2 . Further details of the equilibrator setup and gas analyzer accuracy are given in Amaral et al (2018) and for the chamber design in Barbosa et al (2016).…”

Section: Methodsmentioning

confidence: 99%

Carbon Dioxide Fluxes to the Atmosphere From Waters Within Flooded Forests in the Amazon Basin

et al. 2020

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Inundated tropical forests are underrepresented in analyses of the global carbon cycle and constitute 80% of the surface area of aquatic environments in the lowland Amazon basin. Diel variations in CO2 concentrations and exchanges with the atmosphere were investigated from August 2014 to September 2016 in two flooded forests sites with different wind exposure within the central Amazon floodplain (3°23′S, 60°18′W). CO2 profiles and estimates of air–water gas exchange were combined with ancillary environmental measurements. Surface CO2 concentrations ranged from 19 to 329 μM, CO2 fluxes ranged from −0.8 to 55 mmol m−2 hr−1 and gas transfer velocities ranged from 0.2 to 17 cm hr−1. CO2 concentrations and fluxes were highest during the high water period. CO2 fluxes were three times higher at a site with more wind exposure (WE) compared to one with less exposure (WP). Emissions were higher at the WP site during the day, whereas they were higher at night at the WE site due to vertical mixing. CO2 concentrations and fluxes were lower at the W P site following an extended period of exceptionally low water. The CO2 flux from the water in the flooded forest was about half of the net primary production of the forest estimated from the literature. Mean daily fluxes measured in our study (182 ± 247 mmol m−2d−1) are higher than or similar to the few other measurements in waters within tropical and subtropical flooded forests and highlight the importance of flooded forests in carbon budgets.

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Diffusive methane fluxes from Negro, Solimões and Madeira rivers and fringing lakes in the Amazon basin

Cited by 46 publications

References 73 publications

Radon‐traced pore‐water as a potential source of CO₂ and CH₄ to receding black and clear water environments in the Amazon Basin

Radon‐traced pore‐water as a potential source of CO₂ and CH₄ to receding black and clear water environments in the Amazon Basin

Effect of hydroperiod on CO₂fluxes at the air-water interface in the Mediterranean coastal wetlands of Doñana

Carbon Dioxide Fluxes to the Atmosphere From Waters Within Flooded Forests in the Amazon Basin

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Diffusive methane fluxes from Negro, Solimões and Madeira rivers and fringing lakes in the Amazon basin

Cited by 46 publications

References 73 publications

Radon‐traced pore‐water as a potential source of CO2 and CH4 to receding black and clear water environments in the Amazon Basin

Radon‐traced pore‐water as a potential source of CO2 and CH4 to receding black and clear water environments in the Amazon Basin

Effect of hydroperiod on CO2fluxes at the air-water interface in the Mediterranean coastal wetlands of Doñana

Carbon Dioxide Fluxes to the Atmosphere From Waters Within Flooded Forests in the Amazon Basin

Contact Info

Product

Resources

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Radon‐traced pore‐water as a potential source of CO₂ and CH₄ to receding black and clear water environments in the Amazon Basin

Radon‐traced pore‐water as a potential source of CO₂ and CH₄ to receding black and clear water environments in the Amazon Basin

Effect of hydroperiod on CO₂fluxes at the air-water interface in the Mediterranean coastal wetlands of Doñana