Simulation of Lake Ontario Benthification

Benthification of Lake Ontario has converted it from a pelagically-focused productivity engine to a more benthic system. Large-scale filter-feeding is new to this system and much about mass and energy transfer through the benthic subsystem is unknown. We developed an individual-based, spatially-explicit simulation model of carbon flow through the Lake Ontario benthic system and tested hypotheses of food competition and differential mortality rates to explain the pattern of community change associated with Dreissinid mussel invasion and benthification. The model simulates the physiological processes and population dynamics of three benthic feeding guilds, Filter-feeders [FF] (mussels), Deposit-feeders [DF] (e.g., oligocheates), and Surface Deposit-feeder [SDF] (amphipods), with different larval dispersal strategies. After 150 years of stabilization, FF were introduced, the simulation continued for 10 years, and then FF mortality was increased (due to Round Goby Neobogius melanostomus invasion) for another 10 years. The SDF mortality was either held constant or elevated (representing unknown mortality e.g., disease) during the invasion period. The model was stable and predicted SDF and DF abundances similar to field observations during stabilization and after FF invasion. The elevated SDF mortality scenario represented the spatial pattern of SDF abundance throughout the invasion period better than the constant mortality scenario.