Trophic Status Related to Sediment Chemistry of Canadian Prairie Lakes
1978
Allan, R. J. | Williams, J. D. H.
Concentrations of different sediment phosphorus forms vary in the Prairie lakes studied. Extremely high surface sediment available P concentrations in the Fishing Lakes of southern Saskatchewan were related to P loading from municipal and other cultural sources. Mean available P concentrations in surface sediments from the Fishing Lakes are higher than those found in other Prairie lakes and in most other Canadian lakes. Sediment cores show that presettlement concentrations of available P in the Fishing Lakes are higher than occur today in surface sediments from culturally eutrophied lakes, such as Lake Erie, elsewhere in Canada. Free iron is concentrated in the surface 10 to 15 cm of sediment cores from the Fishing Lakes and Lake Erie. Such a distribution, when coupled to low free Fe/available P ratios, is considered to reflect conditions favorable for P regeneration when anoxic conditions develop under winter ice cover. For the winter of 1976–1977, a mean sediment phosphorus release rate of 8.6 mg/m² per day was calculated for the Fishing Lakes.
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