Patterns in the Growth and the Accumulation of Inorganic Constituents in the Sphagnum Cover on Ombrotrophic Bogs in Scandinavia

Abstract

Three hummock species of Sphagnum mosses (S. fuscum, S. rubellum and S. russowii) and two hollow species (S. balticum and S. magellanicum), characteristic of the moss layer on ombrotrophic bogs in Scandinavia, have been analyzed for N, P, S, Na, K, Mg, Ca, Mn, Fe, Cu, Zn, Cd, Pb, Al and acid insoluble ash (AIA). The moss plants were divided into four segments of predetermined length which were weighed and analyzed separately. Moss weight increases mostly in the capitulum while the main length increase occurs further down. N, P, and K accumulate in the upper parts of the moss carpet, while the concentrations of AIA, Al, Fe, Zn, Cd and Pb increase with the age of the plants. The ion exchange capacity of the mosses determines the concentrations of Na, Mg and Ca; the sum of Ca+Mg being the same throughout the plant. Concentration differences among species result mainly from differences in growth pattern and site conditions. Concentrations in moss layer and underlaying peat are not correlated. A variation between sampling areas is demonstrated for six elements (N, S, Cu, Zn, Cd and Pb) due to a varying supply from man-made emissions, for two elements (Na, Mg) due to varying oceanic influence, and for four elements (P, Na, Mg, Ca) probably due to varying moss productivity. The supply of Al, Fe and AIA is greatest near agricultural and industrialized regions. The variation in Mn is explained by soil and bedrock conditions. Most of the supply of S, Na, Mg and Ca is drained from the moss layer. All other elements are contained in the moss layer and, with the exception of K and Mn, transferred to the peat by litter deposition. It is unlikely that differences in supply of plant nutrients influence the geographical distribution of the bog plants. Hummock species should serve better than hollow species for monitoring current