Examining the past is an important tool for predicting the future. This is especially true when trying to predict the effects of global climate change on lakes and other freshwater ecosystems. Recently, researchers detailed changes in lakes in boreal northeast Ontario associated with changing climate during the Holocene, using paleolimnological methods. The boreal region of northeast Ontario is surprisingly understudied in this context, given its importance as a boundary region between major climate systems.
Queen’s Biology former PhD student Dr. Cale Gushulak, Professor Dr. Brian Cumming, and Professor Dr. Peter Leavitt (Institute of Environmental Change and Society, University of Regina) used records of pollen, pigments, and diatoms spanning the last ~6000 years to describe trends in phototroph composition associated with middle and late Holocene climate change in two small boreal lakes. They also tested whether within-lake variation in limnological parameters can affect the interpretation of paleolimnological records.
Gushulak et al. find evidence of regional climate change in northeast Ontario during the middle and late Holocene. They determine that during the middle-Holocene (~6300 to ~4000 years ago), warmer temperatures contributed to eutrophic conditions and lower lake levels, as identified by phototrophic pigment concentrations and diatom assemblages, respectively. Their results for the middle-Holocene contrast with the late-Holocene (after ~4000 years ago), where cooler and wetter climate led to oligotrophication and higher lake levels. The authors also report differential phototrophic responses to climate variation among adjacent basins from the same lake, highlighting the importance of careful study site consideration when making regional climate predictions.
To learn more, read their article in The Holocene.
