Nonapatite phosphorus concentrations in sediment cores from five mainstem lakes and two sloughs indicate that most Prairie water bodies were eutrophic prior to European settlement and agricultural development of the region. Nonapatite phosphorus increases towards the sediment surface are attributed to urban and/or agricultural effluents. Organic phosphorus increases towards the sediment surface are considered as evidence of post‐settlement increases in lake productivity. Surface sediment increases in nonapatite inorganic phosphorus are the result of urban and/or agricultural effluents modified by upward migration and pooling. Declines in surface sediment nonapatite inorganic phosphorus are evidence of internal loading.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.