 What controls the exchange of water between an embayment and the main body of a lake? The rate of exchange is an important parameter because the water quality can differ between embayments and the main basin. I'm Brian Fluck, and in our recent paper, we study these processes in Lake Simcoe, Canada. We show that as internal waves pump waters between Campnult Bay and Lake Simcoe, the Earth's rotation plays an important role, driving a persistent counterclockwise residual circulation. Most temperate lakes stratify during the summer, resulting in a warm, well-mixed epilimnium sitting on top of a cold, dense hypolimnium. Wind shear across the lake's surface drives large-amplitude internal waves along the thermocline, the interface between the two layers. In large, deep embayments, these thermocline oscillations can act as bellows, pumping the water into and out of the embayment. As the thermocline rises, water above the thermocline is squeezed out of the embayment, while hypolimnetic water is drawn in below, and vice versa as the thermocline sinks. While internal waves have been extensively studied, their potential to drive exchange between deep, connected basins has been largely overlooked. Using data from Campnult Bay, we were able to show that most of the observed horizontal velocities can be explained by this mechanism. Due to the Earth's rotation, as the water masses flow into and out of Campnult Bay, they curl to the right in the direction of travel, resulting in a counterclockwise residual circulation, further driving exchange with the main basin. These processes investigated in our study are relevant for determining the dynamics of water quality parameters used as indicators to evaluate lake health and fish habitat. Campnult Bay is representative of many of the long, narrow, and deep embayments in the Laurentian Great Lakes and elsewhere, suggesting internal wave pumping is likewise driving exchange in these analogous systems.