Temperatures of lakes have been warming under climate change and signs of accelerated transitioning from an oligotrophic state (low in productivity and rich in oxygen) to an eutrophic state (high in nutrients and low in oxygen) have been observed under artificial addition of nutrients from anthropogenic origin. These trends are of particular concern for water quality and the health of the habitat in fish-bearing lakes as they are expected to grow extremes: warmer temperatures, longer stratification periods, and lower dissolved oxygen near the sediments bed.
Previous research has been done to understand effects of these forcings, the emphasis here being on modelling the physical dynamics, such as the vertical stratification and mixing observed. In particular, Christopher J. Young (2016), previously worked on investigating factors influencing temperature-oxygen squeeze (i.e., a reduced window of suitable habitat for fish due to high temperature and low oxygen availability) occurrences in Wood Lake, an eutrophic lake in the Okanagan Valley. He combined field data and predictions from a one-dimensional physical model (DYRESM). Mark Sumka (2017), developed a model to characterize the thermal dynamics of Cultus lake, a mesotrophic transitioning lake in the Fraser Valley, as to assess the impacts of climate change on fish species at risk. Thermal characteristics were modelled using the General Lake Model (GLM) under different warming scenarios using the Canadian Regional Climate Model (CanRCM4). Kathryn Kerker (2020) expanded Sumka’s work by coupling the predictive thermal outputs of Cultus Lake to a temperature-hypoxic volume relationship she developed. Young’s findings show a consistent high correlation between elevated air temperatures and warmer epilimnetic temperatures of Wood Lake, coincident with climate change predictions and increased temperature-related stress on fish. Sumka’s and Kerker’s predictions for Cultus Lake under climate change show an increasing lake heat content, longer period of stratification and a severe depletion of hypolimnetic oxygen concentration. All the results suggest a reduction in suitable habitats for endemic and endangered fish species as a result of changing lake dynamics due to climate change.
Romane’s research, under the supervision of Dr. Laval, focuses on expanding those understandings of lakes’ physical dynamics under climate change and anthropogenic factors by analyzing and modelling a lake subject to different conditions and characteristics. Field data collection on Sx̱ótsaqel (Chilliwack Lake) combined with forecasting scenarios, simulated with GLM, will be used to investigate stratification and mixing trends specific to this lake. As Sx̱ótsaqel is a deep and currently oligotrophic lake, analysis of its physical dynamics in relation to previous results on other lakes could further our understanding of the impacts of climate change and anthropogenic forcings on lakes.
