Modelling CO2 degassing from small acidic rivers using water pCO2, DIC and δ13C-DIC data

Polsenaere, Pierre; Abril, Gwénaël

doi:10.1016/j.gca.2012.05.030

Cited by 77 publications

(101 citation statements)

References 47 publications

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“…CO 2 degassing can occur more rapidly when there is a greater difference between partial pressure of carbon dioxide in the air and in the water, as would be indicated by heightened DIC concentrations [43]. Calculated pCO 2 values based on reported DIC concentrations demonstrated that both tributaries to the AR were supersaturated with carbon dioxide in respect to the theoretical atmospheric value of~390 ppm [44].…”

Section: Sources and Processes Determining Dissolved Inorganic Carbonmentioning

confidence: 99%

Unravelling the Relative Contribution of Dissolved Carbon by the Red River to the Atchafalaya River

DelDuco

2017

Water

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Abstract:The Atchafalaya River (AR), North America's largest swamp river, annually discharges a large volume of freshwater (nearly 200 km 3 ), delivering~25% of the Mississippi River's (MR) flow and the entire Red River's (RR) flow into the Gulf of Mexico. Studies have reported higher levels of organic carbon in the AR's outlets compared to the MR's outlet, raising questions about local carbon sources. In this study, we investigated dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) inputs into the AR from the RR and MR using DOC and DIC concentrations, mass loading, and isotopic signature (δ 13 C) analyses. Monthly river water sampling was conducted in the MR and RR near their confluence where the AR is formed from May 2015 to May 2016. DIC concentrations in the RR were found to be only half of those found in the MR, while the RR's DOC concentrations were on average 1.8 times higher than those found in the MR. Based on the models developed for this study period, the RR's contribution to DIC mass loading in the AR represented 1.41 teragrams (Tg) (or, 29.7%) of the total 4.76 Tg DIC transported by both tributaries, while its contribution to DOC mass loading was disproportionately high, accounting for 1.74 Tg of the 2.75 Tg DOC (or, 63.2% of total DOC) entering the AR. Both δ 13 C DIC and δ 13 C DOC showed significantly more negative values in the RR than those found in the MR. Significant correlation between δ 13 C DIC and δ 13 C DOC isotope values in the RR indicated interrelation of dissolved carbon processing, which was not observable in the MR. These results strongly suggest that the RR is an extremely significant source of DOC to the AR, and thus the Gulf of Mexico, and additionally plays an important role in diluting the anthropogenically enhanced DIC fluxes of the MR.

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Section: Sources and Processes Determining Dissolved Inorganic Carbonmentioning

confidence: 99%

Unravelling the Relative Contribution of Dissolved Carbon by the Red River to the Atchafalaya River

DelDuco

2017

Water

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“…Recent approaches have used stable carbon isotopes of dissolved inorganic carbon to reliably quantify CO 2 outgassing from streams and rivers (Polsenaere and Abril, 2012;Venkiteswaran et al, 2014), in which the model by Venkiteswaran et al (2014) is a parsimonious, simpler version of the model by Polsenaere and Abril (2012). Both apply inverse modelling to calculate the amount of CO 2 lost upstream of a sampling point within a stream or at a catchment outlet.…”

Section: Introductionmentioning

confidence: 99%

“…One clear advantage when compared to conventional methods is that these stable isotope approaches account for the potentially high CO 2 outgassing upstream of any sampling point. Moreover, they incorporate groundwater seeps in first-order headwaters, particularly at low discharge (Polsenaere and Abril, 2012). These factors are typically not covered by conventional methods.…”

Section: Introductionmentioning

confidence: 99%

“…After entering the stream, CO 2 outgassing to the atmosphere increases 13 C / 12 C ratios in the remaining DIC pool because of the well-known equilibrium isotopic fractionation between CO 2 , HCO − 3 , and CO 2− 3 (Myrttinen et al, 2015(Myrttinen et al, , 2012Mook et al, 1974). This predictable and temperature-related process is calculated by the models of Polsenaere and Abril (2012) and Venkiteswaran et al (2014). They are independent of the gas transfer velocity k and account for the upstream portion of a sampling site in headwater streams.…”

Section: Introductionmentioning

confidence: 99%

“…The aim of this work was to model stream CO 2 outgassing on the basis of the stable isotope approach by Polsenaere and Abril (2012) and to extend their method by including measured groundwater stable isotope composition in order to reduce modelling uncertainties. Our study utilises data from the well-studied Uhlířská catchment in the Jizera Mountains (Czech Republic) (Dusek et al, 2012;Sanda et al, 2014;Vitvar et al, 2016;Marx et al, 2017b).…”

Section: Introductionmentioning

confidence: 99%

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Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approach

et al. 2018

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Abstract. A large portion of terrestrially derived carbon outgasses as carbon dioxide (CO 2 ) from streams and rivers to the atmosphere. Particularly, the amount of CO 2 outgassing from small headwater streams is highly uncertain. Conservative estimates suggest that they contribute 36 % (i.e. 0.93 petagrams (Pg) C yr −1 ) of total CO 2 outgassing from all fluvial ecosystems on the globe. In this study, stream pCO 2 , dissolved inorganic carbon (DIC), and δ 13 C DIC data were used to determine CO 2 outgassing from an acidic headwater stream in the Uhlířská catchment (Czech Republic). This stream drains a catchment with silicate bedrock. The applied stable isotope model is based on the principle that the 13 C / 12 C ratio of its sources and the intensity of CO 2 outgassing control the isotope ratio of DIC in stream water. It avoids the use of the gas transfer velocity parameter (k), which is highly variable and mostly difficult to constrain. Model results indicate that CO 2 outgassing contributed more than 80 % to the annual stream inorganic carbon loss in the Uhlířská catchment. This translated to a CO 2 outgassing rate from the stream of 34.9 kg C m −2 yr −1 when normalised to the stream surface area. Large temporal variations with maximum values shortly before spring snowmelt and in summer emphasise the need for investigations at higher temporal resolution. We improved the model uncertainty by incorporating groundwater data to better constrain the isotope compositions of initial DIC. Due to the large global abundance of acidic, humic-rich headwaters, we underline the importance of this integral approach for global applications.

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A review of CO₂ and associated carbon dynamics in headwater streams: A global perspective

Marx

Dušek

Jankovec

et al. 2017

Reviews of Geophysics

251

216

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Terrestrial carbon export via inland aquatic systems is a key process in the global carbon cycle. It includes loss of carbon to the atmosphere via outgassing from rivers, lakes, or reservoirs and carbon fixation in the water column as well as in sediments. This review focuses on headwater streams that are important because their stream biogeochemistry directly reflects carbon input from soils and groundwaters. Major drivers of carbon dioxide partial pressures (pCO2) in streams and mechanisms of terrestrial dissolved inorganic, organic and particulate organic carbon (DIC, DOC, and POC) influxes are summarized in this work. Our analysis indicates that the global river average pCO2 of 3100 ppmV is more often exceeded by contributions from small streams when compared to rivers with larger catchments (> 500 km2). Because of their large proportion in global river networks (> 96% of the total number of streams), headwaters contribute large—but still poorly quantified—amounts of CO2 to the atmosphere. Conservative estimates imply that globally 36% (i.e., 0.93 Pg C yr−1) of total CO2 outgassing from rivers and streams originate from headwaters. We also discuss challenges in determination of CO2 sources, concentrations, and fluxes. To overcome uncertainties of CO2 sources and its outgassing from headwater streams on the global scale, new investigations are needed that should include groundwater data. Such studies would also benefit from applications of integral CO2 outgassing isotope approaches and multiscale geophysical imaging techniques.

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Modelling CO2 degassing from small acidic rivers using water pCO2, DIC and δ13C-DIC data

Cited by 77 publications

References 47 publications

Unravelling the Relative Contribution of Dissolved Carbon by the Red River to the Atchafalaya River

Unravelling the Relative Contribution of Dissolved Carbon by the Red River to the Atchafalaya River

Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approach

A review of CO₂ and associated carbon dynamics in headwater streams: A global perspective

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Modelling CO2 degassing from small acidic rivers using water pCO2, DIC and δ13C-DIC data

Cited by 77 publications

References 47 publications

Unravelling the Relative Contribution of Dissolved Carbon by the Red River to the Atchafalaya River

Unravelling the Relative Contribution of Dissolved Carbon by the Red River to the Atchafalaya River

Groundwater data improve modelling of headwater stream CO&lt;sub&gt;2&lt;/sub&gt; outgassing with a stable DIC isotope approach

A review of CO2 and associated carbon dynamics in headwater streams: A global perspective

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Product

Resources

About

Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approach

A review of CO₂ and associated carbon dynamics in headwater streams: A global perspective