Experimental Lakes Area, Canada

FIGURE 4.2 Concentrations of MeHg (mean 1 standard error) in zooplankton from Lake 240 of the Experimental Lakes Area (northwestern Ontario, Canada), showing seasonal variation during summer and pronounced rapid increases in mean concentration after the fall overturn. (Source Michael J. Paterson, Fisheries and Oceans Canada, Winnipeg, Manitoba, unpublished data.)... 

Brunskill GJ, Wilkinson P. 1987. Annual supply of uranium-238, uranium- 234, thorium-230, radium-226, lead-210, polonium-210 and thorium-232 to lake 239 (Experimental Lakes Area, Ontario, (Canada) from terrestrial and atmospheric sources. Can J Fish Aquat Sci 44(Suppl l) 215-230. 

Figure 15.9. Phosphorus limitations in lakes, (a, b) In experimentally fertilized lakes of the experimental lakes area of the Freshwater Institute in Winnipeg (Environment Canada), ratios of mean annual concentrations C/P and N/P tend to become constant. (From Schindler, 1977.) In (a) we see that the C content increases as a consequence of P addition to the lakes, while (b) illustrates that the N content of a lake increases when the P input is increased, even when little or no nitrogen is added with fertilizer. Each point represents the results of a different lake.

In addition to qnantification of organic constituents directly reflected in the MR absorbance spectra, constitnents not directly observed from the NIR spectra have been quantified. The success of these calibrations probably depends on correlation between the particnlar constituents (e.g., heavy metals), and organic components reflected in the NIR spectra. Malley Williams (1997) modelled the metal composition in the sediments of Lake 382 in the Experimental Lakes Area in north-western Ontario, Canada. The predictive power of the calibration models was generally very good. For instance, the between NIR-predicted metal concentrations and metal concentrations analysed by conventional chemical methods were 0.93 for Zn and Mn, 0.91 for Cu, 0.88 for Ni, 0.86 for Fe, and 0.81 for Pb,... 

Schindler, D.W. 1971. Light, temperature, and oxygen regimes of selected lakes in the Experimental Lakes Area, Northwestern Ontario. J. Fish. Res. Bd Canada 28 157-169. 

---