Chapter 9 - Greenhouse gas emissions from intertidal wetland soils under anthropogenic activities

Abstract

Listen

Translate article

Intertidal wetland soils have been recognized as potential sources of greenhouse gases (GHG), including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), and anthropogenic activities influence the quantities and patterns of the GHG emissions from wetland soils through changing the environmental settings and substrates regulating the productions of the GHGs. The impacts of various anthropogenic activities, including tidal restriction, deforestation, nutrient enrichment on the soil to atmosphere GHG fluxes in intertidal wetlands, are overviewed in this chapter. The responses of GHG emissions from wetlands depend on the species of gases and the anthropogenic activity. Generally, tidal restriction and tide re-establishment change the water saturation of wetland soils, with decomposition of organic carbon in soils altering between aerobic to anaerobic regimes, and also change the sulfate availability in soils to regulate the CH4 emissions. Mangrove clearance causes a decline in CO2 flux from soils over time, owing to the substantial loss of soil organic carbon, while CO2 flux increases with forest age as a consequence of organic matter accumulation in the soils following rehabilitation. Relative to these activities, we suggest that nutrient enrichment or nutrient pollution can largely stimulate the emissions of greenhouse gases from wetland soils, especially N2O. Pollution control and management in coastal areas are therefore essential to reduce greenhouse gas emissions to the atmosphere. Future studies are deserved for better understanding the responses of gas emissions and mechanisms behind the gas productions in wetland soils subjected to anthropogenic activities.