Emma Graves, PhD Candidate, Smol Lab Assessing long-term anthropogenic impacts on lakes within the Rideau Canal system: A paleolimnological assessment The Rideau Canal was constructed in the early-1830s, primarily as a means to transport military personnel, but is now exclusively recreational. The construction of the canal and associated flooding, as well as other land-use changes, likely impacted lakes within the system, but long-term monitoring data are not available. Furthermore, recent environmental changes, including accelerated climate warming, have likely affected lake ecosystems. Paleolimnology can be used to reconstruct these missing data sets. Earlier diatom-based paleolimnological studies were conducted on lakes within the Rideau Canal system ~25-30 years ago and more recently by K. Balasubramaniam (MSc, 2022). However, nothing is known concerning the long-term changes in primary consumer (i.e., Cladocera) assemblages linked to the various environmental disturbances. Using the biological information stored in dated sediment profiles from five lakes within the Rideau Canal system (Opinicon, Upper Rideau, Lower Rideau, Big Rideau, and Indian), my study examines how cladoceran assemblages have changed over the past ~250 years in response to these multiple environmental stressors. Changes linked to canal construction and subsequent flooding are recorded in the sediment profiles. However, the most striking shifts in both diatoms and Cladocera have occurred since the 1970s, with assemblage changes linked to accelerated climate warming. These changes will likely have cascading effects on other ecosystem services.
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