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The greenhouse gas flux and potential global warming feedbacks of a northern macrotidal and microtidal salt marsh

Gail L. Chmura·Lisa Kellman·Glenn R. Guntenspergen
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Abstract

Conversion of wetlands by drainage for agriculture or other anthropogenic activities could have a negative or positive feedback to global warming (GWF). We suggest that a major predictor of the GWF is salinity of the wetland soil (a proxy for available sulfate), a factor often ignored in other studies. We assess the radiative balance of two northern salt marshes with average soil salinities > 20 ppt, but with high (macro-) and low (micro-) tidal amplitudes. The flux of greenhouse gases from soils at the end of the growing season averaged 485 ± 253 mg m -2 h -1 , 13 ± 30 μg m -2 h -1 , and 19 ± 58 μg m -2 h -1 in the microtidal marsh and 398 ± 201 mg m -2 h -1 , 2 ± 26 μg m -2 h -1 , and 35 ± 77 μg m -2 h -1 in the macrotidal marsh for CO 2 , N 2 O, and CH 4 , respectively. High rates of C sequestration mean that loss of these marshes would have a radiative balance of - 981 CO 2 _eq. m -2 yr -1 in the microtidal and - 567 CO 2 _eq. m -2 yr -1 in the macrotidal marsh.

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Gail L. Chmura, Lisa Kellman, Glenn R. Guntenspergen. 2011-11-23. The greenhouse gas flux and potential global warming feedbacks of a northern macrotidal and microtidal salt marsh. https://doi.org/10.1088/1748-9326%2F6%2F4%2F044016

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