Recovery of crustacean zooplankton communities from acid and metal contamination: comparing manipulated and reference lakes

Linking mean body size of pelagic Cladocera to environmental variables in Precambrian Shield lakes: A paleolimnological approach

“…This could be due to direct physiological stress placed on Bosmina through increased metal cycling and acidity, or it could also be a response to a shift in algal assemblages from larger to smaller species (Cattaneo et al 1998). Few lakes in this study had a pH lower than 6.0, and an even stronger size-pH link might therefore be found in a study comparing acidified to neutral lakes (Yan et al 1996). The rare incidence of Daphnia in low pH lakes suggests that Bosmina size trends are the best indicators of pH in these study lakes.…”

Freshwater Diatoms as Indicators of Combined Long-Term Mining and Urban Stressors in Junction Creek (Ontario, Canada)

“…The health of Junction Creek was impacted by the contamination and degradation in its watershed, and showed highly impaired biological integrity [1]. Still nowadays, despite pollution control and rehabilitation actions having been undertaken, aquatic ecosystems in the region suggest slow recovery [2][3][4][5][6]. Mining activities are still present in the region, although under significantly more restrictive pollution control and regulation, and intensification of urban development represents a supplementary environmental threat.…”

Calcium and sodium as regulators of the recovery of four Daphnia species along a gradient of metal and base cations in metal contaminated lakes in Sudbury, Ontario, Canada

“…Recovery of some lakes was also accelerated by addition of calcareous materials (i.e., liming) to these lakes and their watersheds, including Middle and Hannah (Yan et al, 1996b). For example, in 1973, Hannah Lake, which is located only 4.3 km from the main smelter complex, had among the highest metal levels of local urban lakes, averaging 1108 μg L -1 of Cu and 1865 μg L -1 of Ni at a pH of 4.29 (Yan et al, 1996a). By 2006, reflecting diverse restoration efforts and reduced emissions, the concentrations of those metals had plummeted to 20.8 μg L -1 of Cu and 133.0 μg L -1 of Ni (Tab.…”

“…Some would consider a system recovered once all of its dynamic characteristics are restored (for example the return of previous levels of primary production, herbivory, predation, etc.). Others would argue that recovery also requires the restoration of all species with relative abundances resembling those observed either prior to the disturbance or typical of undamaged reference lakes (Yan et al, 1996a). The severity and duration of the historical contamination in Sudbury has complicated ecological recovery, given that so many species disappeared, and potential colonist pools have also been damaged by metal contamination, and possibly by other stressors such as climate change .…”