Geophysical Research Letters

Extreme organic carbon burial fuels intense methane bubbling in a temperate reservoir

Authors

  • Sebastian Sobek,

    1. Eawag: Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
    2. Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland
    3. Now at Department of Ecology and Genetics, Limnology, Uppsala University, Uppsala, Sweden
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  • Tonya DelSontro,

    1. Eawag: Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
    2. Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland
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  • Nuttakan Wongfun,

    1. Eawag: Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
    2. Institute for Water Education, UNESCO-IHE, Delft, Netherlands
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  • Bernhard Wehrli

    1. Eawag: Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
    2. Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland
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Abstract

[1] Organic carbon (OC) burial and greenhouse gas emission of inland waters plays an increasingly evident role in the carbon balance of the continents, and particularly young reservoirs in the tropics emit methane (CH4) at high rates. Here we show that an old, temperate reservoir acts simultaneously as a strong OC sink and CH4 source, because the high sedimentation rate supplies reactive organic matter to deep, anoxic sediment strata, fuelling methanogenesis and gas bubble emission (ebullition) of CH4from the sediment. Damming of the river has resulted in the build-up of highly methanogenic sediments under a shallow water column, facilitating the transformation of fixed CO2 to atmospheric CH4. Similar high OC burial and CH4 ebullition is expected in other reservoirs and natural river deltas.

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