|Müller, DI; Wohlfeil, IC; Christophersen, N; Hauhs, M; Seip, HM: Chemical reactiveness of soil water pathways investigated by point source injections of chloride in a peat bog at Birkenes, J. Hydrology, 144, 101-125 (1993), doi:10.1016/0022-1694(93)90167-8|
At Birkenes, in southernmost Norway, cation exchange processes in peat bogs were investigated under saturated water flow conditions. Previous studies in this catchment have shown the importance of dynamic transport patterns of soil solution as the key to understanding streamwater chemistry. End-Member-Mixing Analysis (EMMA), developed on data from the Birkenes catchment and other sites, has so far been a useful concept in explaining the dynamics of stream chemistry. To obtain further information on the effect of water saturation on the degree of cation exchange during transport of soil solution, sodium chlG,ide was injected into those parts of the peat soils along the main stream that are hydrologically saturated during rainstorms. The active buffer system of the soil matrix was effective in maintaining the level of the cations that were not added as a tracer. The tracer cation was fairly mobile under the experimental conditions, and only limited mobilization of other cations occurred. It is well known, from previous studies, that precipitation entering the catchment may reside there for days before leaving through discharge. The magnitude of cation exchange was less than might have been expected from the previous studies, which also considered hydrologically unsaturated conditions. The residence time during our experiments was probably insufficient for exchange that can be ascribed to classical equilibrium exchange. The extent of hydrodynamic dispersion is important for the magnitude of cation exchange.