Journal article
Carbon dioxide and methane emissions from an artificially drained coastal wetland during a flood: Implications for wetland global warming potential
Journal of Geophysical Research: Biogeosciences, Vol.119(8), pp.1698-1716
2014
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Abstract
<p>Floods frequently produce deoxygenation and acidification in waters of artificially drained coastal acid sulfate soil (CASS) wetlands. These conditions are ideal for carbon dioxide and methane production. We investigated CO<sub>2</sub> and CH<sub>4</sub> dynamics and quantified carbon loss within an artificially drained CASS wetland during and after a flood. We separated the system into wetland soils (inundated soil during flood and exposed soil during post flood period), drain water, and creek water and performed measurements of free CO<sub>2</sub> ([CO<sub>2</sub>*]), CH<sub>4</sub>, dissolved inorganic and organic carbon (DIC and DOC), stable carbon isotopes, and radon (<sup>222</sup>Rn: natural tracer for groundwater discharge) to determine aquatic carbon loss pathways. [CO<sub>2</sub>*] and CH<sub>4</sub> values in the creek reached 721 and 81 μM, respectively, 2 weeks following a flood during a severe deoxygenation phase (dissolved oxygen ~ 0% saturation). CO<sub>2</sub> and CH<sub>4</sub> emissions from the floodplain to the atmosphere were 17-fold and 170-fold higher during the flooded period compared to the post-flood period, respectively. CO<sub>2</sub> emissions accounted for about 90% of total floodplain mass carbon losses during both the flooded and post-flood periods. Assuming a 20 and 100 year global warming potential (GWP) for CH<sub>4</sub> of 105 and 27 CO<sub>2</sub>-equivalents, CH<sub>4</sub> emission contributed to 85% and 60% of total floodplain CO<sub>2-</sub>equivalent emissions, respectively. Stable carbon isotopes (<em>δ</em><sup>13</sup>C in dissolved CO<sub>2</sub> and CH<sub>4</sub>) and <sup>222</sup>Rn indicated that carbon dynamics within the creek were more likely driven by drainage of surface floodwaters from the CASS wetland rather than groundwater seepage. This study demonstrated that >90% of CO<sub>2</sub> and CH<sub>4</sub> emissions from the wetland system occurred during the flood period and that the inundated wetland was responsible for ~95% of CO<sub>2</sub>-equivalent emissions over the floodplain.</p>
Details
- Title
- Carbon dioxide and methane emissions from an artificially drained coastal wetland during a flood: Implications for wetland global warming potential
- Creators
- Jackie R Gatland - Southern Cross UniversityIsaac R Santos - Southern Cross UniversityDamien T Maher - Southern Cross UniversityT M Duncan - Southern Cross UniversityDirk V Erler - Southern Cross University
- Publication Details
- Journal of Geophysical Research: Biogeosciences, Vol.119(8), pp.1698-1716
- Identifiers
- 3438; 991012820868702368
- Academic Unit
- National Marine Science Centre; Centre for Coastal Biogeochemistry; School of Environment, Science and Engineering; Science; Faculty of Science and Engineering
- Resource Type
- Journal article