Determining Peat and Carbon Loss From The Everglades Using Historical Data and Geospatial Techniques.

Climate change due to elevated carbon dioxide levels in the atmosphere presents a long-term threat to the biosphere. The contribution of soil oxidation to global carbon dioxide levels is of growing concern.  For over five millennia, the Everglades has been accreting peat soils and acting as a carbon sink.   Anthropogenic drainage of the Everglades, one of the largest deposits of organic soils in North America, began in the 1880s. Subsequently, the peat soils began subsiding and releasing carbon dioxide (CO₂) into the atmosphere. We quantified subsidence and CO₂ evolution at the regional scale by calculating the changes in peat volume using surface maps reconstructed from historical and current data. We determined the amount of peat that has been lost during the ensuing century, to evaluate the impact of drainage for agricultural development and urbanization on the Everglades. To do this, we used spatially referenced peat surface data gathered within the Everglades Protection Area (EPA) and the Everglades Agricultural Area (EAA). The surfaces created were spatially projected using a Geographic Information System to calculate peat loss and the resultant carbon emissions. For the EAA, the peat surface elevation decreased 1.7 m (5.5 ft) which resulted in carbon dioxide emissions from peat loss on the order 5 x 10⁸ metric tons. The decrease in elevation of the peat surface in Everglades National Park and the Water Conservation Areas ranged from 0.01 to 0.9 m (0.1 to 3.0 ft), with carbon emissions ranging from 0.02 to 0.41 g m² hr^-1. If restoration is successful, some of these regions have the potential of becoming a significant sink for carbon.

Keywords: Everglades; peat; oxidation; subsidence; carbon; carbon dioxide.