The age of river-transported carbon: A global perspective

Carbon cycling; Radiogenic isotope geochemistry; Stable isotope geochemistry; Chemistry of fresh water; global carbon cycle; rivers; organic carbon; 14C; data set; Africa

Abstract :

[en] The role played by river networks in regional and global carbon (C) budgets is receiving increasing attention. Despite the potential of radiocarbon measurements (Δ14C) to elucidate sources and cycling of different riverine C pools, there remain large regions for which no data are available and no comprehensive attempts to synthesize the available information and examine global patterns in the 14C content of different riverine C pools. Here we present new 14C data on particulate and dissolved organic C (POC and DOC) from six river basins in tropical and subtropical Africa and compiled >1400 literature Δ14C data and ancillary parameters from rivers globally. Our analysis reveals a consistent pattern whereby POC is progressively older in systems carrying higher sediment loads, coinciding with a lower organic carbon content. At the global scale, this pattern leads to a proposed global median Δ14C signature of −203‰, corresponding to an age of ~1800 years B.P. For DOC exported to the coastal zone, we predict a modern (decadal) age (Δ14C = +22 to +46‰), and paired data sets confirm that riverine DOC is generally more recent in origin than POC—in contrast to the situation in ocean environments. Weathering regimes complicate the interpretation of 14C ages of dissolved inorganic carbon, but the available data favor the hypothesis that in most cases, more recent organic C is preferentially mineralized.

Research Center/Unit :

FOCUS - Freshwater and OCeanic science Unit of reSearch - ULiège

Disciplines :

Aquatic sciences & oceanology

Author, co-author :

Marwick, Trent R.

Tamooh, Fredrick

Teodoru, Cristian R.

Borges, Alberto ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Océanographie chimique

Darchambeau, François ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Océanographie chimique

Bouillon, Steven

Language :

English

Title :

The age of river-transported carbon: A global perspective

Publication date :

2015

Journal title :

Global Biogeochemical Cycles

ISSN :

0886-6236

eISSN :

1944-9224

Publisher :

Wiley-Blackwell, Washington, United States - District of Columbia

Volume :

Issue :

Pages :

122-137

Peer reviewed :

Peer Reviewed verified by ORBi

Additional URL :

http://dx.doi.org/10.1002/2014GB004911

European Projects :

FP7 - 240002 - AFRIVAL - African river basins: catchment-scale carbon fluxes and transformations.

Name of the research project :

AFRIVAL

Funders :

CE - Commission Européenne

Commentary :

2014GB004911

Available on ORBi :

since 16 March 2015

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Scopus citations^®

202

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197

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123

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223

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