Global carbon dioxide efflux from rivers enhanced by high nocturnal emissions
| Autor: | Matthew J. Cohen, Tom J. Battin, Mark S. Johnson, William H. McDowell, Diego A. Riveros-Iregui, Heli Miettinen, Clément Duvert, Åsa Horgby, Mollie J. McDowell, Marcus B. Wallin, Isaac R. Santos, Emily H. Stanley, Fausto Machado-Silva, Kerry J. Dinsmore, Johan Six, Lishan Ran, Higo J. Dalmagro, Lluís Gómez-Gener, Alex Enrich-Prast, Ryan A. Sponseller, Nicholas S. Marzolf, Lily Kirk, Gerard Rocher-Ros, Travis W. Drake, Shane A. White, Jukka Pumpanen, Hannes Peter, Anne Ojala |
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Daytime
010504 meteorology & atmospheric sciences Naturgeografi global carbon cycle chemistry.chemical_element Nocturnal 010502 geochemistry & geophysics Atmospheric sciences 01 natural sciences Ecology and Environment Carbon cycle Atmospheric Sciences Atmosphere chemistry.chemical_compound Flux (metallurgy) chemistry Physical Geography Carbon dioxide General Earth and Planetary Sciences Environmental science Diel vertical migration Carbon streams and rivers CO2 evasion 0105 earth and related environmental sciences |
| Popis: | Carbon dioxide (CO2) emissions to the atmosphere from running waters are estimated to be four times greater than the total carbon (C) flux to the oceans. However, these fluxes remain poorly constrained because of substantial spatial and temporal variability in dissolved CO2 concentrations. Using a global compilation of high-frequency CO2 measurements, we demonstrate that nocturnal CO2 emissions are on average 27% (0.9 gC m(-2) d(-1)) greater than those estimated from diurnal concentrations alone. Constraints on light availability due to canopy shading or water colour are the principal controls on observed diel (24 hour) variation, suggesting this nocturnal increase arises from daytime fixation of CO2 by photosynthesis. Because current global estimates of CO2 emissions to the atmosphere from running waters (0.65-1.8 PgC yr(-1)) rely primarily on discrete measurements of dissolved CO2 obtained during the day, they substantially underestimate the magnitude of this flux. Accounting for night-time CO2 emissions may elevate global estimates from running waters to the atmosphere by 0.20-0.55 PgC yr(-1). Failing to account for emission differences between day and night will lead to an underestimate of global CO2 emissions from rivers by up to 0.55 PgC yr(-1), according to analyses of high-frequency CO2 measurements. Funding Agencies|Formas grant - National Science Foundation Macrosystems program (NSF) [EF-1442439]; National Science FoundationNational Science Foundation (NSF) [EAR-1847331] |
| Databáze: | OpenAIRE |
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