Dissolved organic carbon and physicochemical variables of peat water in tropical peat swamp forests

Abstract

Degradation of peatlands in Indonesia has been caused by fires, drainage, and deforestation of peat swamp forests. Fires release carbon dioxide (CO2) intensively but occasionally, whereas drainage enhances CO2 emission from the soil and dissolves organic carbon (DOC) leaching through peat water flow. DOC was affected not only by peat degradation but also by the physicochemical variables of peat water. A study on DOC and physicochemical variables of peat water to investigate the effects of drainage and fires has been conducted in three tropical peat swamp forests of Central Kalimantan. They were a relatively intact peat swamp forest with little drainage (UF), a drained peat swamp forest (DF), and a drained, burnt peat swamp forest (DB). The DOC concentration was analyzed using a total organic carbon (TOC) analyzer, while physicochemical variables, including electrical conductivity (EC), pH, and inorganic nitrogen were measured using EC meter, pH meter, and ion analyzer, respectively. Research results showed that the highest DOC concentration was measured in DF, whereas the lowest DOC concentration was in DB. DOC was resulted from peat decomposition due to low pH, low C/N, and high EC conditions. These results indicate that DOC leaching through peat water flow may occur by drainage rather than fires.