GEOCHEMICAL CONTROLS ON PEATLAND PORE-WATER FROM THE HUDSON-BAY LOWLAND - A MULTIVARIATE STATISTICAL APPROACH

Pore-water samples were collected in the Albany River drainage basin o f the Hudson Bay Lowland. The chemistry of these samples was evaluated using bivariate plots, cluster analysis, and principal component anal ysis to determine the importance of groundwater and to evaluate geoche mical processes within the peat. The transport of dissolved constituen ts from the mineral soil into the peat column is a dominant control on peat pore-water chemistry. Peatland landforms have different signatur es for pore-water chemistry; bogs are characterized by elevated concen trations of dissolved organic carbon, CH4, SiO2, K+ and larger mineral ion balance errors, whereas fens are characterized by their higher pH and alkalinity. Large mineral ion balance errors (up to 99%), the inv erse relationship between pH and dissolved organic carbon, and the pos itive correlation between mineral ion balance error and dissolved orga nic carbon show that organic acids are important anions in bog pore wa ters. Methane concentrations and SO42- concentration are inversely rel ated, suggesting that SO42- inhibits CH4 production. Feat pore water a t several locations contains high concentrations of marine salts (SO42 -, Cl-, and Na+) in the lower half of the peat column, indicating that the marine sediments contain sea salts. We suggest that SO42- from th ese marine sediments may reduce methane production in portions of the Hudson Bay Lowland.