Wetlands play an integral role in the global biogeochemical cycling of carbon (C). Historically, research on carbon dynamics in wetlands has focused on large-scale wetlands that are easily recognized on the landscape. However, cryptic wetlands- wetlands that may be small-scale, seasonally inundated, and/or otherwise difficult to identify or characterize on a landscape- occur throughout the Earth’s surface. Agricultural drainage canals represent one type of cryptic wetland environment. Even though they are individually small, the collective imprint of drainage canals across a landscape, especially in low-lying regions where land use is dominated by agriculture, may be large. Herein, we measure CO2 and CH4 emissions from agricultural drainage canals at the Timberlake Observatory for Wetland Restoration in Tyrrell County, North Carolina. Our findings indicate that the inclusion of agricultural drainage canals in the measured GHG fluxes from Timberlake increases site CO2 and CH4 emissions by ca. 1% each. Therefore, agricultural drainage canals may be an unrecognized source of C-fluxes in low-lying regions of the Earth dominated by cropland.

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