Oceanic CO 2 outgassing and biological production hotspots induced by pre-industrial river loads of nutrients and carbon in a global modeling approach
Rivers are a major source of nutrients, carbon and alkalinity to the global ocean. In this study, we firstly estimate pre-industrial riverine loads of nutrients, carbon and alkalinity based on a hierarchy of weathering and terrestrial organic matter export models, while identifying regional hotspots...
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ftdoajarticles:oai:doaj.org/article:dbd761d9c4da4924b0a4cbad6e235451 2023-05-15T15:17:51+02:00 Oceanic CO 2 outgassing and biological production hotspots induced by pre-industrial river loads of nutrients and carbon in a global modeling approach F. Lacroix T. Ilyina J. Hartmann 2020-01-01T00:00:00Z https://doi.org/10.5194/bg-17-55-2020 https://doaj.org/article/dbd761d9c4da4924b0a4cbad6e235451 EN eng Copernicus Publications https://www.biogeosciences.net/17/55/2020/bg-17-55-2020.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-17-55-2020 1726-4170 1726-4189 https://doaj.org/article/dbd761d9c4da4924b0a4cbad6e235451 Biogeosciences, Vol 17, Pp 55-88 (2020) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2020 ftdoajarticles https://doi.org/10.5194/bg-17-55-2020 2022-12-31T09:24:20Z Rivers are a major source of nutrients, carbon and alkalinity to the global ocean. In this study, we firstly estimate pre-industrial riverine loads of nutrients, carbon and alkalinity based on a hierarchy of weathering and terrestrial organic matter export models, while identifying regional hotspots of the riverine exports. Secondly, we implement the riverine loads into a global ocean biogeochemical model to describe their implications for oceanic nutrient concentrations, net primary production (NPP) and air–sea CO 2 fluxes globally, as well as in an analysis of coastal regions. Thirdly, we quantitatively assess the terrestrial origins and the long-term fate of riverine carbon in the ocean. We quantify annual bioavailable pre-industrial riverine loads of 3.7 Tg P, 27 Tg N, 158 Tg Si and 603 Tg C delivered to the ocean globally. We thereby identify the tropical Atlantic catchments (20 % of global C), Arctic rivers (9 % of global C) and Southeast Asian rivers (15 % of global C) as dominant suppliers of carbon for the ocean. The riverine exports lead to a simulated net global oceanic CO 2 source of 231 Tg C yr −1 to the atmosphere, which is mainly caused by inorganic carbon (source of 183 Tg C yr −1 ) and by organic carbon (source of 128 Tg C yr −1 ) riverine loads. Additionally, a sink of 80 Tg C yr −1 is caused by the enhancement of the biological carbon uptake from dissolved inorganic nutrient inputs from rivers and the resulting alkalinity production. While large outgassing fluxes are simulated mostly in proximity to major river mouths, substantial outgassing fluxes can be found further offshore, most prominently in the tropical Atlantic. Furthermore, we find evidence for the interhemispheric transfer of carbon in the model; we detect a larger relative outgassing flux (49 % of global riverine-induced outgassing) in the Southern Hemisphere in comparison to the hemisphere's relative riverine inputs (33 % of global C inputs), as well as an outgassing flux of 17 Tg C yr −1 in the Southern Ocean. The addition of ... Article in Journal/Newspaper Arctic Southern Ocean Directory of Open Access Journals: DOAJ Articles Arctic Southern Ocean Biogeosciences 17 1 55 88 |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
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Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 F. Lacroix T. Ilyina J. Hartmann Oceanic CO 2 outgassing and biological production hotspots induced by pre-industrial river loads of nutrients and carbon in a global modeling approach |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Rivers are a major source of nutrients, carbon and alkalinity to the global ocean. In this study, we firstly estimate pre-industrial riverine loads of nutrients, carbon and alkalinity based on a hierarchy of weathering and terrestrial organic matter export models, while identifying regional hotspots of the riverine exports. Secondly, we implement the riverine loads into a global ocean biogeochemical model to describe their implications for oceanic nutrient concentrations, net primary production (NPP) and air–sea CO 2 fluxes globally, as well as in an analysis of coastal regions. Thirdly, we quantitatively assess the terrestrial origins and the long-term fate of riverine carbon in the ocean. We quantify annual bioavailable pre-industrial riverine loads of 3.7 Tg P, 27 Tg N, 158 Tg Si and 603 Tg C delivered to the ocean globally. We thereby identify the tropical Atlantic catchments (20 % of global C), Arctic rivers (9 % of global C) and Southeast Asian rivers (15 % of global C) as dominant suppliers of carbon for the ocean. The riverine exports lead to a simulated net global oceanic CO 2 source of 231 Tg C yr −1 to the atmosphere, which is mainly caused by inorganic carbon (source of 183 Tg C yr −1 ) and by organic carbon (source of 128 Tg C yr −1 ) riverine loads. Additionally, a sink of 80 Tg C yr −1 is caused by the enhancement of the biological carbon uptake from dissolved inorganic nutrient inputs from rivers and the resulting alkalinity production. While large outgassing fluxes are simulated mostly in proximity to major river mouths, substantial outgassing fluxes can be found further offshore, most prominently in the tropical Atlantic. Furthermore, we find evidence for the interhemispheric transfer of carbon in the model; we detect a larger relative outgassing flux (49 % of global riverine-induced outgassing) in the Southern Hemisphere in comparison to the hemisphere's relative riverine inputs (33 % of global C inputs), as well as an outgassing flux of 17 Tg C yr −1 in the Southern Ocean. The addition of ... |
format |
Article in Journal/Newspaper |
author |
F. Lacroix T. Ilyina J. Hartmann |
author_facet |
F. Lacroix T. Ilyina J. Hartmann |
author_sort |
F. Lacroix |
title |
Oceanic CO 2 outgassing and biological production hotspots induced by pre-industrial river loads of nutrients and carbon in a global modeling approach |
title_short |
Oceanic CO 2 outgassing and biological production hotspots induced by pre-industrial river loads of nutrients and carbon in a global modeling approach |
title_full |
Oceanic CO 2 outgassing and biological production hotspots induced by pre-industrial river loads of nutrients and carbon in a global modeling approach |
title_fullStr |
Oceanic CO 2 outgassing and biological production hotspots induced by pre-industrial river loads of nutrients and carbon in a global modeling approach |
title_full_unstemmed |
Oceanic CO 2 outgassing and biological production hotspots induced by pre-industrial river loads of nutrients and carbon in a global modeling approach |
title_sort |
oceanic co 2 outgassing and biological production hotspots induced by pre-industrial river loads of nutrients and carbon in a global modeling approach |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/bg-17-55-2020 https://doaj.org/article/dbd761d9c4da4924b0a4cbad6e235451 |
geographic |
Arctic Southern Ocean |
geographic_facet |
Arctic Southern Ocean |
genre |
Arctic Southern Ocean |
genre_facet |
Arctic Southern Ocean |
op_source |
Biogeosciences, Vol 17, Pp 55-88 (2020) |
op_relation |
https://www.biogeosciences.net/17/55/2020/bg-17-55-2020.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-17-55-2020 1726-4170 1726-4189 https://doaj.org/article/dbd761d9c4da4924b0a4cbad6e235451 |
op_doi |
https://doi.org/10.5194/bg-17-55-2020 |
container_title |
Biogeosciences |
container_volume |
17 |
container_issue |
1 |
container_start_page |
55 |
op_container_end_page |
88 |
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1766348109998194688 |