The paleolimnology of Haynes Lake, and Teapot Lake, Ontario: documenting anthropogenic disturbances within Canada's largest city

Abstract

Haynes Lake is a small kettle lake located on the Oak Ridges Moraine (ORM), Ontario, and is within the Greater Toronto Area (GTA); Canada's most populous region. The ORM is an important recharge and discharge area for ground water and drinking water in the GTA, and is a natural habitat for a diverse array of plant and animal species. Diatoms and thecamoebians extracted from Haynes Lake sediment cores were used as biological proxies to quantify changes in water chemistry through time, and thus infer changes in the limnology and ecosystem biology. High-resolution details of the sedimentary history of the lake were determined through x-ray analysis of the sediment cores. There were three periods of disturbance to the Haynes Lake ecosystem from ca A.D. 656 through to ca A.D. 2003 which were significant enough to cause major changes in lake sedimentation, the diatom flora, and thecamoebian fauna. The first disturbance was concomitant with Iroquoian population expansion in the area during the period from A.D. 1300 to A.D. 1550. The second period of disturbance occurred between ca. A.D. 1670 -1750 following the first appearance of European settlers in the area. The most severe disturbance to the ecosystem, however, occurred ca A.D. 1890 due to increased erosion caused by a growing population of European settlers in the vicinity who cleared land for agriculture, housing and built a road adjacent to the lake.