Estimating mercury concentrations and fluxes in the water column and sediment of Lake Ontario with HERMES model.

The HERMES model-predicted Hg concentrations and fluxes in Lake Ontario were based on twelve lake and drainage basin variables (i.e., water temperature, precipitation rate, air Hg, surface area, mean depth, water volume, water inflow rate, inflow water Hg, inflow and lake suspended particulate matter, air-water and water-air mass transfer coefficients, and sedimentation rate).

Development of resource shed delineation in aquatic ecosystems.

We apply a concept derived from food web ecology to large-scale spatial patterns of material supply within and between watersheds and coasts by generalizing the definition "resource shed" to source areas for materials supplied to a receptor (e.g., a point location) over a specified time interval.

Changes in fractal dimension during aggregation.

Experiments were performed to evaluate temporal changes in the fractal dimension of aggregates formed during flocculation of an initially monodisperse suspension of latex microspheres. Particle size distributions and aggregate geometrical information at different mixing times were obtained using a non-intrusive optical sampling and digital image analysis technique, under variable conditions of mixing speed, coagulant (alum) dose and particle concentration. Pixel resolution required to determine aggregate size and geometric measures including the fractal dimension is discussed and a quantitative measure of accuracy is developed.