Impact of Human Activities on the Carbon Cycle
Human activities have accelerated decomposition in wetland ecosystems, destabilizing carbon stocks in them. In particular, global climate change, drainage and atmospheric deposition are key activities that affect wetland carbon cycle substantially. Global climate change can affect carbon decomposition in wetlands by warming effects as well as more frequent droughts. Elevated CO2 itself can increase dissolved organic carbon leaching from wetlands through enhanced primary production. For coastal wetlands, sea level rise can also affect carbon mineralization by changes in water chemistry as well as oxygen availability. Wetlands have been subject to drainage for the development of agricultural fields and urban dwellings which can accelerate carbon decomposition by aeration. Finally, nitrogen and sulfur deposition can either increase or inhibit carbon decomposition depending on the nutrient status and locations. Overall, human activities can accelerate carbon decomposition in wetlands resulting in greater carbon releases into the atmosphere as CO2 or CH4, and into the aquatic ecosystems as DOC.