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July 15, 2010 Acknowledgements: T.E.A.M., Ontario
<--Click the icon for a PowerPoint presentation
by the PEARL, Queen's University researchers on "Assessment of water
quality using paleoecological indicators" (download the free PowerPoint Viewer 2003 from Microsoft if needed); or click for the PDF version
A paleolimnological study of several indicator lakes is being carried out by the PEARL (Paleoecological Environmental Assessment and Research Laboratory), Kingston, Ontario researchers. This is the first ever such study undertaken anywhere in the Maritimes.
"The environmental, ecological, economic, and social consequences of declining water-quality are of critical national and global importance. The two most significant water-quality issues related to inland waters in large parts of eastern Canada remain lake acidification and eutrophication.
Due to the lack of long-term data sets, it is impossible to measure directly the extent of degradation (or possible recovery) in water quality. Fortunately, new approaches are available to reconstruct these missing data. This 5-year, multi-disciplinary, program combines novel paleolimnological (using information archived in lake sediments to reconstruct environmental conditions) and biogeochemical modeling approaches to address key issues related to water-quality changes in Nova Scotia and southern New Brunswick. Long-term goals are to develop pattern- and process-based models on regional scales to help address the diversity of water-quality issues facing eastern Canada. These techniques will be widely applicable to other regions.
To achieve these objectives, a series of strategic projects will be undertaken to address key processes related to acidification and eutrophication, and their interactions with other environmental stressors (e.g. climate change). Consequently, short-term goals are to apply new approaches to provide detailed information on the trajectories of changes in water quality that have occurred in specific lakes of interest to our users. This will allow us to determine if individual lakes are deteriorating or improving in water quality, and to determine what levels of stressors or pollutants result in detrimental water-quality changes (e.g. what are the critical loads for each lake? At what level of sulphate deposition do we see the first signs of acidification or at what level of watershed development does eutrophication become a problem? Are hypolimnetic oxygen levels in NS brook trout lakes decreasing? If so, what are the causes?). Moreover, by reconstructing pre-impact, background conditions, we will establish realistic mitigation targets (i.e., are these lakes naturally acidic or naturally eutrophic or do they naturally suffer from deepwater oxygen depletions?). These data will also provide insights into biogeochemical processes and models so that more realistic assessments of environmental change will be possible."
The phosphorus management policy of Canadian Council of Ministers of the Environment (CCME) clearly requires establishing the background values in pristine conditions, i.e., natural background values (or pre-human impact). These can only be obtained by predictive TP modelling utilizing phosphorus export coefficients in similar pristine subwatersheds and/or by paleo techniques which can generate inference models to the pre-human impact era.
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