Mechanistic modelling of the global fate of carbon in river basins
Abstract
Rivers and streams may play a significant role in the global carbon (C) cycle, their contribution however, remains highly uncertain as global measurement data are sparse. Here we use a global coupled hydrology-biogeochemistry framework to quantify the fate of inorganic and organic forms of C in riverine systems. We constrain C inputs into the fluvial network using the surrounding lithology, soil organic C content, land cover and climate data. Based on calculations of in-stream biogeochemical processes between inorganic and organic carbon and changing hydrological conditions along the riverine continuum, we quantify the spatially explicit lateral transport, atmospheric exchange, burial and biogeochemical transformations. In this presentation, we evaluate four in-stream process schemes to quantify their effects on the fate of C in global freshwater systems on the global scale. We simulated a passive pipe, a passive chimney, a respiration river and a production-respiration river and eventually compared the export of dissolved and particulate forms of organic and inorganic C and riverine CO2 emissions. Also, export for major rivers is validated with measurement data. The estimated global lateral total C transport is 1.8 ± 0.4 Pg/yr with 1.3 ± 0.8 Pg/yr riverine CO2 emissions. Although major uncertainties remain, these results imply that riverine C fluxes and transformations are key aspects in the global C cycle and need further research.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B23L2697V
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCESDE: 0428 Carbon cycling;
- BIOGEOSCIENCES