Variation in the C/N-Quotient of Peat in Relation to Decomposition Rate and Age Determination with 210 Pb

Abstract

Peat profiles .apprx. 0.5 m in depth through bog hummocks with Sphagnum spp. were studied on a subarctic mire in northern Sweden and on some bogs in southern Sweden. The C/N-quotient in the peat decreases with depth due to losses in C during the decay process. As a result of decay and compaction, the annual peat volume increment at the bottom of the profiles is 4-15% of the increment in the upper parts. On the central bog areas in southern Sweden the decay processes during periods are interrupted at earlier stages, which gives rise to a more rapid volumetric peat increment than in the marginal bog areas and in the north. Datings from 210Pb activity have proved to be reliable only in the lower parts of the profiles (age > 50 yr) as Pb might be mobile in the upper parts. At the deposition in the catotelm layer after a period of at least 150 yr the organic matter has lost up to 80% of its original C. The accumulation of 210P and N shows that the supply of these elements is higher in southern Sweden than in the north.