BIOM&S Seminar: Numerical simulation of future bottom water dissolved oxygen concentration in small lakes

SPEAKER:   Aidin Jabbari, Dept. Integrative Biology

ABSTRACT:

Lake trout are a valuable resource, whose populations are becoming increasingly threatened from multiple stressors, including climate warming, eutrophication and over-exploitation. Declines in deep-water dissolved oxygen concentrations in lakes where nutrient inputs have remained steady or decreased; particularly in remote lakes that are far away from direct human impacts, raises the level of concern about climate warming as a threat-multiplier. As part of a multidisciplinary NSERC strategic grant that includes researchers at Queen's and York universities and scientists from Environment Canada, a simple oxygen sub-model has been embedded in the one-dimensional bulk mixed-layer thermodynamic Canadian Small Lake Model. This model is currently being incorporated into the land surface component of the Canadian Regional Climate Model. Future bottom water oxygen predictions from three different future climate scenarios show a decrease from ~5.5 mg/l in 1975-2015 to ≤3.5 mg/l in 2070-2100 in small lakes. This drop is associated with less production of oxygen in the bottom water and increased sediment oxygen demand due to the future climate warming. This model and the findings of this study will provide managers with a useful tool to ensure sustainable fishery resources for future generations.