Use of Bomb-Produced 14C to Evaluate the Amount of CO2 Emanating from Two Peat Bogs in Finland

Abstract

We used moss increment counting to obtain well-defined samples of the topmost peat layers of two Sphagnum fuscum hummocks. The two ombrotrophic bogs, Lakkasuo in central Finland and Korvinsuo in eastern Finland, are of different ages, covering 3 and 9 ka, respectively. Using AMS dating, we traced bomb-produced ¹⁴C through the topmost parts of the two peat profiles. A well-defined ¹⁴C activity peak was found in both sequences dating the corresponding layer to ad 1965. A comparison between the maximum peat activities and the corresponding atmospheric values for the period of interest provides an opportunity to evaluate the amount of CO₂ emanating from the decaying peat bog, and taken up by the living sphagnum plants.Considerable variations in δ¹³C values were also observed. These variations indicate, at least partly, annual variations in the emission rate of CO₂ from decomposition of older peat in the bog, and are connected with climatic factors such as temperature and precipitation.