Global-scale daily riverine DOC fluxes from lands to the oceans with a generic model

The export of riverine dissolved organic carbon (DOC) to the oceans is determinant in carbon exchanges of the estuaries and oceanic food webs. Past research returned a global DOC export around 160–450 TgC.yr−1 by using complex process-based models or yearly average estimates that could have been mis...

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Bibliographic Details
Published in:Global and Planetary Change
Main Authors: Fabre, Clément, Simeoni-Sauvage, Sabine, Probst, Jean-Luc, Sanchez-Pérez, José Miguel
Other Authors: Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier 2020
Subjects:
Modélisation et simulation
Ecologie
Environnement
DOC
Global scale
Generic model
Daily
Riverine exports
Arctic
Climate change
Online Access:https://oatao.univ-toulouse.fr/26703/
https://oatao.univ-toulouse.fr/26703/1/Fabre_26703.pdf
https://doi.org/10.1016/j.gloplacha.2020.103294
Description
Summary:The export of riverine dissolved organic carbon (DOC) to the oceans is determinant in carbon exchanges of the estuaries and oceanic food webs. Past research returned a global DOC export around 160–450 TgC.yr−1 by using complex process-based models or yearly average estimates that could have been misjudged. In this study, we try to understand the complex processes explaining daily DOC exports among 341 exoreic watersheds covering 71% of freshwater flows to the oceans. Based on a dataset of DOC concentrations among rivers at the global scale, we were able to link DOC concentrations to daily discharge, the ration between the soil organic carbon content and the amount of precipitations and the average air temperature in the watersheds. We have found a global riverine DOC flux of 131.6 TgC.yr−1 based on daily data and a generic model. Tropical and cold watersheds are the main contributors with 49.5% and 33.3% of the global riverine DOC flux on the two last decades while temperate, semi-arid and polar basins represent 15.9%, 0.7% and 0.6%, respectively. Temporal exports range from 0.1 to 0.16 TgC.day−1 in tropical areas, 0.03–0.32 TgC.day−1 in cold areas and 0.03–0.08 TgC.day−1 in temperate areas. Atlantic and Arctic oceans receive the most important fluxes (0.12–0.2 and 0.01–0.26 TgC.day−1). In a climate change context, this generic equation could be introduced in hydrological modelling tools to predict future DOC fluxes trends.

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