Presentations

QUANTIFYING SPATIAL AND TEMPORAL TRANSFER OF MERCURY FROM UPLAND TO LOWLAND IN FORESTED WATERSHED OF KEJIMKUJIK NATIONAL PARK, NS
  In watersheds, forests play an important role in sequestering, retaining and, transferring atmospheric and geogenic derived mercury (Hg), from uplands to wetlands and surface water futures. This study focuses on quantifying these processes and attempts to provide a geospatial framework for modeling Hg accumulation within forest watersheds from uplands to wetlands as affected through time by varying vegetation and soil conditions within forested watersheds. With this framework, several geo-spatial sampling studies were used to identify differences in total organic carbon (TOC), total and methyl Hg concentrations by type of freshwater environment (surface water and groundwater-fed systems) and seasonal high to low flow conditions. It is demonstrated that scavenged atmospheric Hg by the forest canopy is allocated to forest biomass production and partitioning process. Hydrological calculations were used to determine the rate of dissolved organic carbon (DOC) and Hg leaching from the forest soil based on the soil-internal DOC production (Forest Hydrology Model). The subsequent leaching rate was then partitioned into surface and sub-surface water flow, with the former carrying the soil produced Hg-DOC combination, while the latter loosing this combination through continued DOC and Hg retention in the soil. The model-estimated Hg concentrations were calibrated with the corresponding field determinations for (i) the forest biomass components, (ii) the upland soil layers, and (iii) the concentrations in soil leachates and stream water.