Exploring Spatially Explicit Changes in Carbon Budgets of Global River Basins during the 20th Century

• Published in: Environmental science & technology Vol. 55; no. 24; pp. 16757 - 16769
• Main Authors: van Hoek, Wim J, Wang, Junjie, Vilmin, Lauriane, Beusen, Arthur H W, Mogollón, José M, Müller, Gerrit, Pika, Philip A, Liu, Xiaochen, Langeveld, Joep J, Bouwman, Alexander F, Middelburg, Jack J
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 21.12.2021
• Subjects: 20th century; Arctic Regions; Arid regions; Arid zones; Basins; Carbon; Carbon cycle; Carbon dioxide; Carbon dioxide emissions; Climate change; Dissolved inorganic carbon; Dissolved organic carbon; Dissolved Organic Matter; Emissions; Environmental changes; Environmental conditions; Fluxes; Fresh Water; Headwaters; Humans; Hydrology; Inland waters; Land use; Lithology; Nutrient cycles; Oceans; Polar environments; River basins; River networks; Rivers; Spatial distribution; Terrestrial environments; Tropical environments; Arctic Regions; river fluxes; process-based hydrology-biogeochemistry model; global budget; spatiotemporal variations; carbon biogeochemistry
• DOI: 10.1021/acs.est.1c04605
• ISSN: 0013-936X

Rivers play an important role in the global carbon (C) cycle. However, it remains unknown how long-term river C fluxes change because of climate, land-use, and other environmental changes. Here, we investigated the spatiotemporal variations in global freshwater C cycling in the 20th century using the mechanistic IMAGE-Dynamic Global Nutrient Model extended with the Dynamic In-Stream Chemistry Carbon module (DISC-CARBON) that couples river basin hydrology, environmental conditions, and C delivery with C flows from headwaters to mouths. The results show heterogeneous spatial distribution of dissolved inorganic carbon (DIC) concentrations in global inland waters with the lowest concentrations in the tropics and highest concentrations in the Arctic and semiarid and arid regions. Dissolved organic carbon (DOC) concentrations are less than 10 mg C/L in most global inland waters and are generally high in high-latitude basins. Increasing global C inputs, burial, and CO emissions reported in the literature are confirmed by DISC-CARBON. Global river C export to oceans has been stable around 0.9 Pg yr . The long-term changes and spatial patterns of concentrations and fluxes of different C forms in the global river network unfold the combined influence of the lithology, climate, and hydrology of river basins, terrestrial and biological C sources, in-stream C transformations, and human interferences such as damming.