Dissolved organic carbon export from a cutover and restored peatland

Abstract High demand for horticultural peat has increased peatland drainage and peat extraction in Canada. The hydrology and carbon cycling of these cutover peatlands is greatly altered, necessitating active restoration efforts to permit the regeneration of Sphagnum mosses and the re‐establishment of natural peatland function. The effect of peatland extraction and restoration on the export of dissolved organic carbon (DOC) was examined for three successive seasons (May to October, 1999 to 2001) at two different sites (cutover and restored) in eastern Québec. A shift towards higher DOC concentrations was observed following peatland extraction (maximum: 182·6 mg L −1 ) and concentrations remained high post‐restoration (maximum: 191·0 mg L −1 ). The cutover site exported more DOC than the restored site in all three study seasons. The highest exports occurred during the wettest year (1999), with cutover and restored site export of 10·3 and 4·8 g m −2 , respectively. In 2000, 8·5 g C m −2 was released from the cutover site, while the restored site released less than half that amount (3·4 g C m −2 ). In 2001, the restored site released about the same amount of DOC as in the previous year (3·5 g C m −2 ), while the cutover site load dropped to 6·2 g C m −2 . Both sites were net exporters of DOC in all years. Copyright © 2007 John Wiley & Sons, Ltd.