Organic matter sources, fluxes and greenhouse gas exchange in the Oubangui River (Congo River basin)

Abstract. The Oubangui is a major tributary of the Congo River, draining an area of ~500 000 km2 mainly consisting of wooded savannahs. Here, we report results of a one year long, 2-weekly sampling campaign in Bangui (Central African Republic) since March 2010 for a suite of physico-chemical and biogeochemical characteristics, including total suspended matter (TSM), bulk concentration and stable isotope composition of particulate organic carbon (POC and δ13CPOC), particulate nitrogen (PN and δ15NPN), dissolved organic carbon (DOC and δ13CDOC), dissolved inorganic carbon (DIC and δ13CDIC), dissolved greenhouse gases (CO2, CH4 and N2O), and dissolved lignin composition. δ13C signatures of both POC and DOC showed strong seasonal variations (−30.6 to −25.8‰, and −31.8 to −27.1‰, respectively), but their different timing indicates that the origins of POC and DOC may vary strongly over the hydrograph and are largely uncoupled, differing up to 6‰ in δ13C signatures. Dissolved lignin characteristics (carbon-normalised yields, cinnamyl:vanillyl phenol ratios, and vanillic acid to vanillin ratios) showed marked differences between high and low discharge conditions, consistent with major seasonal variations in the sources of dissolved organic matter. We observed a strong seasonality in pCO2, ranging between 470 ± 203 ppm for Q

• Publication year

  2012

• Venue

  Biogeosciences

• Publication date

  2012-06-08

• Fields of study

  Chemistry, Environmental Science

• Identifiers
  DOI 10.5194/BG-9-2045-2012
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar

• No claims are published for this paper.

• No concepts are published for this paper.

• The role of rivers in the regional carbon balance

  2013cited by this paper
• Water and Chemical Budgets at the Catchment Scale Including Nutrient Exports from Intact Forests and Disturbed Landscapes

  2013cited by this paper
• Dissolved organic carbon dynamics in a UK podzolic moorland catchment: linking storm hydrochemistry, flow path analysis and sorption experiments

  2012cited by this paper
• Factors controlling water‐column respiration in rivers of the central and southwestern Amazon Basin

  2012cited by this paper
• An initial investigation into the organic matter biogeochemistry of the Congo River

  2012cited by this paper
• The carbon balance of Africa: synthesis of recent research studies

  2011influential reference
• Riverine coupling of biogeochemical cycles between land, oceans, and atmosphere

  2011influential reference
• Freshwater Methane Emissions Offset the Continental Carbon Sink

  2011influential reference
• Carbon isotopes as tracers of dissolved organic carbon sources and water pathways in headwater catchments

  2011cited by this paper
• Physical controls on carbon dioxide transfer velocity and flux in low‐gradient river systems and implications for regional carbon budgets

  2011cited by this paper
• Nitrogen enrichment and the emission of nitrous oxide from streams

  2011cited by this paper
• Significant efflux of carbon dioxide from streams and rivers in the United States

  2011influential reference
• Illuminated darkness: Molecular signatures of Congo River dissolved organic matter and its photochemical alteration as revealed by ultrahigh precision mass spectrometry

  2010cited by this paper
• Carbon isotope compositions of terrestrial C3 plants as indicators of (paleo)ecology and (paleo)climate

  2010cited by this paper
• Seasonal variability of methane in the rivers and lagoons of Ivory Coast (West Africa)

  2010influential reference
• Nitrous oxide emission from denitrification in stream and river networks

  2010cited by this paper
• Nitrous oxide emissions from a large, impounded river: the Ohio River.

  2010cited by this paper
• Temperature-controlled organic carbon mineralization in lake sediments

  2010cited by this paper
• Comparison of XAD with other dissolved lignin isolation techniques and a compilation of analytical improvements for the analysis of lignin in aquatic settings.

  2010influential reference
• Distribution, origin and cycling of carbon in the Tana River (Kenya): a dry season basin-scale survey from headwaters to the delta

  2009cited by this paper
• Large CO2 disequilibria in tropical lakes

  2009cited by this paper
• Terrestrial and fluvial carbon fluxes in a tropical watershed: Nyong basin, Cameroon

  2009influential reference
• Photochemical degradation of dissolved organic matter and dissolved lignin phenols from the Congo River

  2009cited by this paper
• Seasonal Variability of Carbon Dioxide in the Rivers and Lagoons of Ivory Coast (West Africa)

  2009cited by this paper
• Linking soils and streams: Sources and chemistry of dissolved organic matter in a small coastal watershed

  2009cited by this paper
• Temporal controls on dissolved organic matter and lignin biogeochemistry in a pristine tropical river

  2009cited by this paper
• A review of material transport by the Congo River and its tributaries

  2009influential reference
• Nitrous oxide emissions from tropical hydroelectric reservoirs

  2008influential reference
• The influence of historical and potential future deforestation on the stream flow of the Amazon River – Land surface processes and atmospheric feedbacks

  2008cited by this paper
• Deforestation in Central Africa: Estimates at regional, national and landscape levels by advanced processing of systematically-distributed Landsat extracts

  2008influential reference
• A preliminary estimate of organic carbon transport by the Ayeyarwady (Irrawaddy) and Thanlwin (Salween) Rivers of Myanmar

  2008influential reference
• Carbon isotope fractionation of dissolved inorganic carbon (DIC) due to outgassing of carbon dioxide from a headwater stream

  2008cited by this paper
• Biophysical controls on organic carbon fluxes in fluvial networks

  2008influential reference
• Changes in Atmospheric Constituents and in Radiative Forcing. Chapter 2

  2007cited by this paper
• Landscape scale controls on the vascular plant component of dissolved organic carbon across a freshwater delta

  2007cited by this paper
• Determination of delta18O of water and delta13C of dissolved inorganic carbon using a simple modification of an elemental analyser-isotope ratio mass spectrometer: an evaluation.

  2007cited by this paper
• Plumbing the Global Carbon Cycle: Integrating Inland Waters into the Terrestrial Carbon Budget

  2007cited by this paper
• THE ROLE OF SORPTION IN CONTROL OF RIVERINE DISSOLVED ORGANIC CARBON CONCENTRATIONS BY RIPARIAN ZONE SOILS IN THE AMAZON BASIN

  2007influential reference
• Fractionation of lignin during leaching and sorption and implications for organic matter “freshness”

  2007cited by this paper
• A new automated setup for stable isotope analysis of dissolved organic carbon

  2006influential reference
• Physiogeographic features of the Oubangui catchment and environmental trends reflected in discharge and floods at Bangui 1911–1999, Central African Republic

  2005cited by this paper
• Prevalence of Heterotrophy and Atmospheric CO2 Emissions from Aquatic Ecosystems

  2005cited by this paper
• Spatial and seasonal dynamics of total suspended sediment and organic carbon species in the Congo River

  2005influential reference
• Spatial and seasonal dynamics of total suspended sediment and organic carbon species in the Congo River - art. no. GB4019

  2005influential reference
• Young organic matter as a source of carbon dioxide outgassing from Amazonian rivers

  2005cited by this paper
• Organic carbon transported by the equatorial rivers: example of Congo-Zaire and Amazon basins.

  2004cited by this paper
• Variation in surface turbulence and the gas transfer velocity over a tidal cycle in a macro-tidal estuary

  2003cited by this paper
• Stable isotope ecology in the Ituri Forest

  2003cited by this paper
• Gas transfer velocities of CO2 in three European estuaries (Randers Fjord, Scheldt, and Thames)

  2003cited by this paper
• Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2

  2002cited by this paper
• Organic carbon fluxes to the ocean from high-standing islands

  2002cited by this paper
• Transport and diagenesis of dissolved and particulate terrigenous organic matter in the North Pacific Ocean

  2002cited by this paper
• Consistency of patterns in concentration‐discharge plots

  2002cited by this paper
• Spatiotemporal variations in hydrological regimes within Central Africa during the XXth century

  2001influential reference
• Dissolved inorganic carbon in a highly polluted estuary (the Scheldt)

  2001influential reference
• Gas exchange in rivers and estuaries: Choosing a gas transfer velocity

  2001influential reference
• Emissions of nitrous oxide (N2O) from a tidal, freshwater river, the Hudson River, New York.

  2001cited by this paper
• Carbon in catchments: connecting terrestrial carbon losses with aquatic metabolism

  2001cited by this paper
• Transport of terrestrial organic carbon to the oceans by rivers: re-estimating flux- and burial rates

  2000cited by this paper
• Causes of concentration/discharge hysteresis and its potential as a tool for analysis of episode hydrochemistry

  1998cited by this paper
• Terrestrial sedimentation and the carbon cycle: Coupling weathering and erosion to carbon burial

  1998influential reference
• Tracing of Weathering Reactions and Water Flowpaths: A Multi-isotope Approach

  1998cited by this paper
• The effects of climate changes on river baseflow and aquifer storage in Central Africa.

  1997cited by this paper
• Biogeochemical control on the temporal variability of trace element concentrations in the Oubangui river (Central African Republic)

  1996cited by this paper
• Predicting the oceanic input of organic carbon by continental erosion

  1996cited by this paper
• Overview of a simple model describing variation of dissolved organic carbon in an upland catchment

  1996cited by this paper
• Early diagenesis of vascular plant tissues: Lignin and cutin decomposition and biogeochemical implications

  1995cited by this paper
• Caractérisation chimique de la fraction organique des suspensions du fleuve Congo

  1995influential reference
• CONCENTRATIONS, FLUCTUATIONS SAISONNIERES ET FLUX DE CARBONE DANS LE BASSIN DU CONGO

  1995cited by this paper
• Carbon river fluxes and weathering CO2 consumption in the Congo and Amazon river basins

  1994influential reference
• Forest sources and pathways of organic matter transport to a blackwater stream: a hydrologic approach

  1994cited by this paper
• Fate of methane in the Hudson River and Estuary

  1993cited by this paper
• Dissolved major elements exported by the Congo and the Ubangi rivers during the period 1987–1989

  1992cited by this paper
• Geomorphic/Tectonic Control of Sediment Discharge to the Ocean: The Importance of Small Mountainous Rivers

  1992cited by this paper
• Intérêt de la mesure du δ13C des sols en milieu naturel equatorial pour la connaissance des aspects pédologiques et écologiques des relations savane-forêt: exemples du Congo

  1991influential reference
• Carbon isotope composition and geochemistry of particulate organic matter in the Congo River (Central Africa): Application to the study of Quaternary sediments off the mouth of the river

  1991cited by this paper
• Biogeochemistry of carbon in the Amazon River

  1990cited by this paper
• Seasonal dynamics in methane emissions from the Amazon River floodplain to the troposphere

  1990cited by this paper
• Hydrology and geochemistry of the Congo river system

  1987cited by this paper
• Methane in surface waters of Oregon estuaries and rivers1

  1987cited by this paper
• Compositions and fluxes of particulate organic material in the Amazon River1

  1986influential reference
• Carbon, nitrogen, and phosphorus transport by world rivers

  1982cited by this paper
• Characterization of lignin by gas capillary chromatography of cupric oxide oxidation products

  1982cited by this paper
• Determinations of Carbon Dioxide and Methane by Dual Catalyst Flame Ionization Chromatography and Nitrous Oxide by Electron Capture Chromatography

  1981cited by this paper
• Nitrous oxide solubility in water and seawater

  1980influential reference
• The characterization of plant tissues by their lignin oxidation products

  1979cited by this paper
• The Thermodynamics of the Carbonate System in Seawater

  1979cited by this paper
• Solubility of methane in distilled water and seawater

  1976influential reference
• Mechanism of Reaeration in Natural Streams

  1958influential reference

• Tropical wet season runoff mobilises younger carbon in rainforest streams but older carbon in agricultural streams

  2026cites this paper
• Aquatic and soil CO2 emissions from forested wetlands of Congo's Cuvette Centrale

  2025cites this paper
• Reconstructing central African hydroclimate over the past century using freshwater bivalve shell geochemistry

  2025cites this paper
• Role of synthetic fertilizers on stable isotope ratios of particulate organic matter in the Godavari River

  2025cites this paper
• Assessing the tropical Atlantic biogeochemical processes in the Norwegian Earth System Model

  2024cites this paper
• Precipitation fuels dissolved greenhouse gas (CO2, CH4, N2O) dynamics in a peatland-dominated headwater stream: results from a continuous monitoring setup

  2024cites this paper
• Organic matter processing by heterotrophic bacterioplankton in a large tropical river: Relating elemental composition and potential carbon mineralization

  2024cites this paper
• Hydrology drives export and composition of carbon in a pristine tropical river

  2023influential citation
• Seasonal changes of dissolved organic matter chemistry and its linkage with greenhouse gas emissions in saltmarsh surface water and porewater interactions.

  2023cites this paper
• GRiMeDB: the Global River Methane Database of concentrations and fluxes

  2023cites this paper
• Global Riverine Export of Dissolved Lignin Constrained by Hydrology, Geomorphology, and Land‐Cover

  2023cites this paper
• Tritium and 14C dependencies upon particulate organic matter within the nuclearized Rhone River (France)

  2022cites this paper
• Drivers of water quality in Afromontane-savanna rivers

  2022cites this paper
• The Seasonal Dynamics of Organic and Inorganic Carbon along the Tropical Usumacinta River Basin (Mexico)

  2022cites this paper
• Carbon fluxes in a carbonate rock dominated microbasin of the Quadrilátero Ferrífero, Brazil

  2022cites this paper
• GRiMeDB: The global river database of methane concentrations and fluxes

  2022cites this paper
• Low N2O and variable CH4 fluxes from tropical forest soils of the Congo Basin

  2022cites this paper
• Fluvial Carbon Dynamics across the Land to Ocean Continuum of Great Tropical Rivers

  2022cites this paper
• Dynamique du carbone fluvial dans le continuum terre‐océan des grands fleuves tropicaux : l'Amazone et le Congo

  2022cites this paper
• Sediment Balance Estimation of the ‘Cuvette Centrale’ of the Congo River Basin Using the SWAT Hydrological Model

  2021influential citation
• Spatial–temporal variations in riverine carbon strongly influenced by local hydrological events in an alpine catchment

  2021cites this paper
• Freshwater bivalve shells as hydrologic archives in the Congo Basin

  2021cites this paper
• Evaluating Freshwater Mussel Shell δ13C Values as a Proxy for Dissolved Inorganic Carbon δ13C Values in a Temperate River

  2021cites this paper
• Evolution of the Dissolved Organic Matter Composition along the Upper Mekong (Lancang) River

  2021cites this paper
• Partitioning carbon sources in a tropical watershed (Nyong River, Cameroon) between wetlands and terrestrial ecosystems – Do CO2 emissions from tropical rivers offset the terrestrial carbon sink?

  2021cites this paper
• Sources and main controls of dissolved organic and inorganic carbon in river basins: A worldwide meta-analysis

  2021cites this paper
• Distinct concentration‐discharge dynamics in temperate streams and rivers: CO2 exhibits chemostasis while CH4 exhibits source limitation due to temperature control

  2021cites this paper
• Organic Matter Composition of Biomineral Flocs and Its Influence on Suspended Particulate Matter Dynamics Along a Nearshore to Offshore Transect

  2021cites this paper
• Particulate Organic Carbon in the Tropical Usumacinta River, Southeast Mexico: Concentration, Flux, and Sources

  2021influential citation
• Interactive comment on “Historical and future contributions of inland waters to the Congo basin

  2020cites this paper
• Land-use intensity alters both the source and fate of CO2 within eight sub-tropical estuaries

  2020cites this paper
• Carbon dynamics and CO₂ and CH₄ outgassing in the Mekong delta

  2020cites this paper
• Historical and future contributions of inland waters to the Congo basin 1 carbon balance 2

  2020cites this paper
• Spatial-temporal variations in riverine carbon strongly influenced by local hydrological events in an alpine headwater stream

  2020cites this paper
• Assessing δ15N values in the carbonate-bound organic matrix and periostracum of bivalve shells as environmental archives

  2020cites this paper
• Carbon gas flux to and from inland waters: support for a global observation network

  2020cites this paper
• Historical and future contributions of inland waters to the Congo Basin carbon balance

  2020influential citation
• Effects of aquatic phototrophs on seasonal hydrochemical, inorganic, and organic carbon variations in a typical karst basin, Southwest China

  2019cites this paper
• Relationship between river water chemistry and shell chemistry of two tropical African freshwater bivalve species

  2019cites this paper
• Spatial and temporal variations of dissolved greenhouse gases ( CO 2 , CH 4 , N 2 O ) in the Congo River network

  2019cites this paper
• Large spatiotemporal shifts of CO2 partial pressure and CO2 degassing in a monsoonal headwater stream

  2019cites this paper
• Update on the fluid geochemistry monitoring time series for geothermal systems in Dominica, Lesser Antilles island arc: 2009–2017

  2019cites this paper
• Variations of dissolved greenhouse gases (CO2, CH4, N2O) in the Congo River network overwhelmingly driven by fluvial-wetland connectivity

  2019cites this paper
• Nitrous oxide (N2O) and methane (CH4) in rivers and estuaries of northwestern Borneo

  2019cites this paper
• Variations in dissolved greenhouse gases (CO2, CH4, N2O) in the Congo River network overwhelmingly driven by fluvial-wetland connectivity

  2019cites this paper
• Organic carbon transfers in the subtropical Red River system (Viet Nam): insights on CO2 sources and sinks

  2018cites this paper
• Spatio-temporal variability and controls on methane and nitrous oxide in the Guadalquivir Estuary, Southwestern Europe

  2018cites this paper
• Seasonal variation of organic matter characteristics and fluoride concentration in the Maji ya Chai River (Tanzania): Impact on treatability by nanofiltration/reverse osmosis.

  2018cites this paper
• Interactive comment on “ Impact of peatlands on carbon dioxide ( CO 2 ) emissions from the Rajang River and Estuary , Malaysia ” by Denise

  2018cites this paper
• Carbon dynamics and CO 2 and CH 4 outgassing in the Mekong delta

  2018cites this paper
• Food Web Structure and Trophic Relations in a Riverine Mangrove System of the Tropical Eastern Pacific, Central Coast of Colombia

  2018influential citation
• Terrestrial carbon inputs to inland waters: A current synthesis of estimates and uncertainty

  2018cites this paper
• Interactions between iron and organic carbon in a sandy beach subterranean estuary

  2018cites this paper
• Molecular Structure Characterization of Riverine and Coastal Dissolved Organic Matter with Ion Mobility Quadrupole Time-of-Flight LCMS (IM Q-TOF LCMS).

  2018cites this paper
• Calibration of hydroclimate proxies in freshwater bivalve shells from Central and West Africa

  2017cites this paper
• Understanding terrestrial organic carbon export : a time-series approach

  2017influential citation
• Carbon dynamics of river corridors and the effects of human alterations

  2017influential citation
• Shifts in the carbon dynamics in a tropical lowland river system (Tana River, Kenya) during flooded and non-flooded conditions

  2017cites this paper
• Organic Matter Preservation and Sequestration through the Synergistic Ferric Carbon Shuttle

  2017cites this paper
• Flux des gaz à effet de serre (CH4 et N2O) dans le fleuve Niger en amont de Niamey (Niger)

  2017cites this paper
• Seasonal and inter-annual variations in carbon fluxes in a tropical river system (Tana River, Kenya)

  2017cites this paper
• Stable isotope mass balances versus concentration differences of dissolved inorganic carbon – implications for tracing carbon turnover in reservoirs

  2017cites this paper
• Stable isotope analysis of dissolved organic carbon in Canada's eastern coastal waters

  2017cites this paper
• Spatial patterns of DOC concentration and DOM optical properties in a Brazilian tropical river‐wetland system

  2017cites this paper
• Hydrologic controls on seasonal and inter-annual variability of Congo River particulate organic matter source and reservoir age

  2017cites this paper
• The Genesis and Exodus of Vascular Plant DOM from an Oak Woodland Landscape

  2017cites this paper
• Connecting tropical river DOM and POM to the landscape with lignin

  2017cites this paper
• A high-resolution carbon balance in a small temperate catchment: Insights from the Schwabach River, Germany

  2017cites this paper
• The riverine source of CH4 and N2O from the Republic of Congo, western Congo Basin

  2017cites this paper
• Phytoplankton dynamics in the Congo River

  2017cites this paper
• Carbon dynamics in the Mekong Delta

  2017cites this paper
• A comprehensive biogeochemical record and annual flux estimates for the Sabaki River (Kenya)

  2017cites this paper
• Multiple plant-wax compounds record differential sources and ecosystem structure in large river catchments

  2016cites this paper
• Apports En Carbone Et Azote Dans Le Fleuve Niger À Tondibia (Niamey) : Résultats De Deux (2) Ans D’observations

  2016influential citation
• Origins, seasonality, and fluxes of organic matter in the Congo River

  2016cites this paper
• Greenhouse gas emissions from natural ecosystems and agricultural lands insub-Saharan Africa: synthesis of available data and suggestions for furtherresearch

  2016influential citation
• Faecal indicator bacteria and organic carbon in the Red River, Viet Nam : measurements and modelling

  2016cites this paper
• The fluvial flux of particulate organic matter from the UK: the emission factor of soil erosion

  2016cites this paper
• Influence of catchment land use and seasonality on dissolved organic matter composition and ecosystem metabolism in headwater streams of a Kenyan river

  2016cites this paper
• Evaluating the effects of diel-cycling hypoxia and pH on growth and survival of juvenile summer flounder Paralichthys dentatus

  2016influential citation
• Shift in the chemical composition of dissolved organic matter in the Congo River network

  2016cites this paper
• Aberystwyth University Greenhouse gas emissions from natural ecosystems and agricultural lands in sub-Saharan Agrica

  2016influential citation
• Seasonal variation of organic matter concentration and characteristics in the Maji ya Chai River (Tanzania): Impact on treatability by ultrafiltration.

  2016cites this paper
• Chapter 11 – Riverine DOM

  2015cites this paper
• Riverine N2O production, emissions and export from a region dominated by agriculture in Southeast Asia (Jiulong River)

  2015cites this paper
• Globally significant greenhouse-gas emissions from African inland waters

  2015cites this paper
• Lateral carbon fluxes and CO 2 outgassing from a tropical peat-draining river

  2015cites this paper
• River geochemistry, chemical weathering, and atmospheric CO2 consumption rates in the Virunga Volcanic Province (East Africa)

  2015influential citation
• Dynamics in organic matter processing, ecosystem metabolism and trophic sources for consumers in the Mara River, Kenya

  2015cites this paper
• Reviews and syntheses: Greenhouse gas emissions in natural and agricultural lands in sub-Saharan Africa: synthesis of available data and suggestions for further studies

  2015cites this paper
• Organic matter characterization and distribution in sediments of the terminal lobes of the Congo deep-sea fan: Evidence for the direct influence of the Congo River

  2015cites this paper
• Greenhouse Gas Emissions

  2015cites this paper
• Mineralization of soil colloids by aerobic heterotrophic bacteria of soils

  2015cites this paper
• Water-atmosphere greenhouse gas exchange measurements using FTIR spectrometry

  2015cites this paper
• Riverbed methanotrophy sustained by high carbon conversion efficiency

  2015cites this paper
• Dynamics of greenhouse gases (CO2, CH4, N2O) along the Zambezi River and major tributaries, and their importance in the riverine carbon budget

  2015cites this paper
• The biogeochemistry of carbon across a gradient of streams and rivers within the Congo Basin

  2014cites this paper
• Intertwining the elemental cycles of iron and carbon: Iron’s influence on the fate and dynamics of organic carbon in the environment

  2014cites this paper
• Spatial variability and temporal dynamics of greenhouse gas (CO2, CH4, N2O) concentrations and fluxes along the Zambezi River mainstem and major tributaries

  2014cites this paper
• Paradigm shifts in soil organic matter research affect interpretations of aquatic carbon cycling: transcending disciplinary and ecosystem boundaries

  2014cites this paper