Development of hypoxic waters in multi-basin coastal waters of a large lake

We investigate the hypoxia development in the multi-basin nearshore waters of Lake Erie using lake-wide observations and a high-resolution three-dimensional model with the ability to resolve the predominant offshore and nearshore physical processes including coastal upwelling events (5-10 days), near-inertial waves (18 hours), surface seiches (14 hours) and dissolved oxygen (DO). The upwelling events are the predominant physical processes driving nearshore-offshore exchanges and are energized lake-wide in response to strong winds when the epilimnetic waters are advected to the offshore, causing the hypolimnetic waters to move up into the nearshore zones. When the wind subsides, the advected waters into the nearshore are returned to offshore. During these events, the nearshore apparent redox potential at the sediment-water interface significantly decreases due to the replacement with offshore waters creating favorable biochemical conditions to elevate the sequence of events coupled with the substantial decrease of pH and DO. We use observations and the model results to delineates lake-wide nearshore zones affected by the development of hypoxia.