Hydrology, development, and biogeochemistry of ombrogenous peat bogs with special reference to nutrient relocation in a western Newfoundland bog

Abstract

Ombrogenous bogs differ fundamentally from other peatlands in their hydrology, and this affects peat accumulation and bog development as well as the elemental concentrations in peat and water. In oceanic and northern parts of the raised bog zone, the surface of the bog center remains below the critical profile of the water mound because factors other than moisture supply limit its maximum height. In the surface peat, Na and K decrease with depth, whereas other elements increase to a greater or smaller extent. Most elements occur in surprisingly low concentrations below the anaerobic level. In an ombrotrophic bog in western Newfoundland, Na, Mg, and Ca concentrations of bog water were 5, 4–5, and 0.5 times higher, respectively, than in precipitation. K and Mg increased downslope, especially in spring, but not during the vegetation season. In July and August, 20–30% of the Mg, 75–80% of the K, and 93% of the Ca are removed from the precipitation while the water seeps over the bog. Uptake by vegetation is primarily responsible, but Ca is mostly adsorbed on the peat. Increased water flow, rather than higher nutrient concentration, appears to account for the occurrence of more nutrient-demanding species, such as Nymphaea odorata and Utricularia vulgaris, in the pools of the lower slope.