Fluvial carbon dioxide emission from the Lena River basin during the spring flood
Greenhouse gas (GHG) emission from inland waters of permafrost-affected regions is one of the key factors of circumpolar aquatic ecosystem response to climate warming and permafrost thaw. Riverine systems of central and eastern Siberia contribute a significant part of the water and carbon (C) export...
| Published in: | Biogeosciences |
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| Main Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Copernicus Publications
2021
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| Subjects: | |
| Online Access: | https://doi.org/10.5194/bg-18-4919-2021 https://doaj.org/article/b804f63fac934a0d9db1fe726018a330 |
| Summary: | Greenhouse gas (GHG) emission from inland waters of permafrost-affected regions is one of the key factors of circumpolar aquatic ecosystem response to climate warming and permafrost thaw. Riverine systems of central and eastern Siberia contribute a significant part of the water and carbon (C) export to the Arctic Ocean, yet their C exchange with the atmosphere remains poorly known due to lack of in situ GHG concentration and emission estimates. Here we present the results of continuous in situ p CO 2 measurements over a 2600 km transect of the Lena River main stem and lower reaches of 20 major tributaries (together representing a watershed area of 1 661 000 km 2 , 66 % of the Lena's basin), conducted at the peak of the spring flood. The p CO 2 in the Lena (range 400–1400 µatm ) and tributaries (range 400–1600 µatm ) remained generally stable (within ca. 20 %) over the night–day period and across the river channels. The p CO 2 in tributaries increased northward with mean annual temperature decrease and permafrost increase; this change was positively correlated with C stock in soil, the proportion of deciduous needleleaf forest, and the riparian vegetation. Based on gas transfer coefficients obtained from rivers of the Siberian permafrost zone ( k =4.46 m d −1 ), we calculated CO 2 emission for the main stem and tributaries. Typical fluxes ranged from 1 to 2 <math xmlns="http://www.w3.org/1998/Math/MathML" id="M10" display="inline" overflow="scroll" dspmath="mathml"><mrow class="unit"><mi mathvariant="normal">g</mi><mspace width="0.125em" linebreak="nobreak"/><mi mathvariant="normal">C</mi><mspace linebreak="nobreak" width="0.125em"/><msup><mi mathvariant="normal">m</mi><mrow><mo>-</mo><mn mathvariant="normal">2</mn></mrow></msup><mspace width="0.125em" linebreak="nobreak"/><msup><mi mathvariant="normal">d</mi><mrow><mo>-</mo><mn ... |
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