| Autor: |
Tamara Michaelis, Felicitas Kaplar, Thomas Baumann, Anja Wunderlich, Florian Einsiedl |
| Jazyk: |
angličtina |
| Rok vydání: |
2024 |
| Předmět: |
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| Zdroj: |
Scientific Reports, Vol 14, Iss 1, Pp 1-16 (2024) |
| Druh dokumentu: |
article |
| ISSN: |
2045-2322 |
| DOI: |
10.1038/s41598-024-54760-z |
| Popis: |
Abstract Ebullition transports large amounts of the potent greenhouse gas methane (CH $$_4$$ 4 ) from aquatic sediments to the atmosphere. River beds are a main source of biogenic CH $$_4$$ 4 , but emission estimates and the relative contribution of ebullition as a transport pathway are poorly constrained. This study meets a need for more direct measurements with a whole-year data set on CH $$_4$$ 4 ebullition from a small stream in southern Germany. Four gas traps were installed in a cross section in a river bend, representing different bed substrates between undercut and slip-off slope. For a comparison, diffusive fluxes were estimated from concentration gradients in the sediment and from measurements of dissolved CH $$_4$$ 4 in the surface water. The data revealed highest activity with gas fluxes above 1000 ml m $$^{-2}$$ - 2 d $$^{-1}$$ - 1 in the center of the stream, sustained ebullition during winter, and a larger contribution of ebullitive compared to diffusive CH $$_4$$ 4 fluxes. Increased gas fluxes from the center of the river may be connected to greater exchange with the surface water, thus increased carbon and nutrient supply, and a higher sediment permeability for gas bubbles. By using stable isotope fractionation, we estimated that 12-44% of the CH $$_4$$ 4 transported diffusively was oxidized. Predictors like temperature, air pressure drop, discharge, or precipitation could not or only poorly explain temporal variations of ebullitive CH $$_4$$ 4 fluxes. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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