Original paper

Effects of a prescribed fire on dissolved inorganic carbon dynamics in a nutrient-enriched Everglades wetland

Gu, Binhe; Miao, ShiLi; Edelstein, Chris; Dreschel, Thomas

Abstract

The purpose of this study was to assess the short-term response of dissolved inorganic carbon (DIC) chemistry to a prescribed fire in a nutrient-enriched area of the Everglades. Surface water samples were analyzed for water temperature, pH, total carbon (TC) and DIC concentrations in the burn area, in addition to one upstream and two downstream stations, pre- and post-fire for a period of 14 weeks. Dissolved free carbon dioxide (CO2), the partial pressure of CO2 (pCO2) and CO2 flux between surface water and the atmosphere were calculated. Although a large amount of unburned litter remained in the burned area and an immediate increase in the DIC concentration was observed post-fire, the average DIC concentration at the burn area was only slightly higher than the upstream station and lower than the two downstream stations. Similarly, CO2 concentrations and pCO2 at the burn area were lower than those of the three control stations. The low CO2 and pCO2 immediately post-fire were likely attributed to the elevated pH due to the addition of basic ash. However, the continuously low CO2 and pCO2 were the combined results of high pH and increased CO2 sequestration by the growth of periphyton triggered by increased availability of light and growth space. These factors also explain why the DIC concentration at the burn area did not show a dramatic increase after the fire. Overall, our results suggest that despite decreases in pCO2 post-burn, this wetland continues to act as a net source of CO2 to the atmosphere.

Keywords

dissolved inorganic carbon (dic)co2pco2co2 fluxevergladesprescribed firewetland