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HIGH METHANE EMISSIONS FROM A MID-LATITUDE AGRICULTURAL RESERVOIR
Citation:
Beaulieu, J., R. Smolenski, C. Nietch, A. Townsend-Small, AND M. Elovitz. HIGH METHANE EMISSIONS FROM A MID-LATITUDE AGRICULTURAL RESERVOIR. To be Presented at Joint Aquatic Sciences Meeting, Portland, OR, May 18 - 23, 2014.
Impact/Purpose:
To inform the public
Description:
To assess the magnitude of methane (CH4) emissions from reservoirs in agricultural regions, we measured CH4 emission rates from William H. Harsha Lake, located in southwestern Ohio, USA, over a thirteen month period. The reservoir was a strong source of CH4¬ throughout the year, emitting on average 176 ± 36 g C m-2 d-1, which is comparable to reports from tropical reservoirs. The river - reservoir transition zone emitted CH4 at rates an order of magnitude higher than the rest of the reservoir and was the source of 64% of annual reservoir-CH4 emissions, despite comprising only 5% of the reservoir surface area. Total carbon emissions (i.e., CH4 + CO2) were also greater at the transition zone, indicating that the river delta supported greater carbon mineralization rates than elsewhere. We suggest that reservoir-CH4 emissions could be mitigated by reducing the areal extent of the river delta through water level management. This work indicates that mid-latitude agricultural reservoirs may compose a larger fraction of the global CH4 budget than currently thought and that these emissions may be mitigated through reservoir management.