Pekka Pakarinen , Kimmo Tolonen

Rikin huuhtoutuminen pintaturpeesta

Pakarinen P., Tolonen K. Rikin huuhtoutuminen pintaturpeesta.

Tiivistelmä

Four ombrotrophic Sphagnum fuscum peat profiles (0—50 cm) were analyzed for total sulphur. The study sites include two bogs from southern Finland (Munasuo and Suurisuo, 60—61 °N) plus two bogs from northern Finland (Jänkävuopaja and Ah-venjärvenvuoma, 67°N). Sulphur was determined gravimetrically with BaSO4- method (Horwitz 1965). Sulphur concentrations and their vertical distributions are indicated in Figs. 2—3. In the top layer (0—20 cm) the S content is low, between 0.5 and 1.0 mg/g dry weight. In the southern Finnish sites, higher values were found near the transition from aerobic to anaerobic conditions: in Munasuo at ca. 30 cm level and in Suurisuo at 45—50 cm level (Fig. 2). In northern Finnish sites, especially in Ahvenjärvenvuoma, the S concentrations of Sphagnum peat seem to be related to the dry volume weight (degree of humification) (Fig. 3), but further material will be needed to establish the commonness of "enrichment layer" of sulphur in these peats. The sulphur amounts per square meter for 0—20 cm and 20—50 cm layers are indicated in Table 1. In the 0—20 cm layer, which was in all sites weakly humified, it was possible to apply the moss dating method (Pakarinen & Tolonen 1977). Using the ages obtained for the top 20 cm layer (23 to 68 years), the annual accumulation rates of sulphur were found to range from 59 to 163 mg/m2 (Table 1). The estimated atmospheric sulphur deposition rates in the corresponding areas varied from 280 to 650 mg/m2 (according to data of Buch 1960, Haapala 1977, Järvi-nen 1978). Thus the retention % of S was estimated at 19 to 25 for the surface peat layer (0—20 cm), and it was concluded that the main part of the atmospheric S deposition is leached to deeper peat layers or more probably outside the mire ecosystem.

Vastaanotettu 31.10.2017 Julkaistu 1.1.1980

Katselukerrat 1388

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