Effects of Climate Warming on Dissolved Oxygen Concentrations in Lake Erie

This is the authors' abstract. We don't add key points for this paper.

A coupled hydrodynamic and water quality model was used to examine the response of dissolved oxygen concentrations to warming of the central basin of Lake Erie. An area-averaged hydrodynamic model was used to estimate the lake temperatures and thermocline variability as forced by surface heating and winds. Vertical turbulence mixing processes were incorporated by a second-moment, turbulence closure submodel. The water quality model comprised a set of 15 mass balance equations that predicted distributions of phytoplankton biomass, nutrient concentration, and dissolved oxygen. A synthesis of the results from the coupled model forced by climate warming scenarios from three atmospheric general circulation models suggested that there will be a substantial decline in oxygen concentrations in the central basin. Although forecasts of future conditions that are beyond established experiences are uncertain, it appears likely that climate warming will lead to such a decline regardless of details in changes of lake stratification dynamics. Losses of 1 mg/L of dissolved oxygen in the upper layers and of 1–2 mg/L in the lower layers of Lake Erieˈs central basin can be expected, along with an increase in the area of the lake that is anoxic. The decline in dissolved oxygen is predicted to be due to warmer lake temperatures, which increase the rate of bacterial activity in the hypolimnion waters and sediment, rather than to thermocline location and volume of water below the thermocline.