Lake Clear, Ontario

Seston-S deposition probably is a more important process than dissimilatory reduction in lakes with low [SO42 ]. As lakewater sulfate concentrations increase, seston deposition reaches a plateau limited by the overall primary production rate and the maximum algal S content, but diffusive fluxes continue to increase in direct proportion to [SO42 ]. Thus, in highly acidic lakes (pH 3 5 [SOjt2 J > 100 peq/L), such as McCloud Lake, Florida and Lake 223, Ontario, dissimilatory sulfate reduction probably is the major sulfate sink. Nriagu and Soon (131 concluded that endproducts of dissimilatory reduction and elevated sediment S content would not be observed below S mg/L (240 / eq/L), but we see clear evidence of dissimilatory reduction in Little Rock Lake at concentrations of approximately SO /teq/L. 

Schindler, D. W., and J. E. Nighswander. 1970. Nutrient supply and primary production in Clear Lake, eastern Ontario. J. Fish. 

Fig. 25. Series of towers comprising part of the heavy water production plant at Ontario Hydro s Bruce nuclear power complex near Tiverton on the shores of Lake Huron. Heavy water is a clear, colorless liquid that looks and tastes like ordinary water. It occurs naturally in ordinary water in the proportion of approximately one part heavy water to 7000 parts of ordinary water. While ordinary water is a combination of hydrogen and oxygen (H20), heavy water (D.-1.0) is made of up of deuterium—a form, or isotope, of hydrogen—and oxygen. Deuterium is heavier than hydrogen in that it has an extra neutron in its atomic nucleus, so heavy water weighs about 10% more than ordinary water. It also has different freezing and boiling points. It is the extra neutron that makes heavy water more suitable than ordinary water for use in CANDU nuclear reactors as both a moderator and a heat transport medium. (Ontario Hydro, Toronto, Ontario, Canada)...

Pearson et al. [19,42] determined the accumulation of PCDD/F homologs in sediment cores from two control lakes near Lake Superior, Lake Superior, Lake Michigan, and Lake Ontario in 1994 (Fig. 8). There were no clear maxima for PCDDs accumulation rates in Lake Superior cores. However, there were maxima around 1960-1970 for PCDFs in the depositional zone of... 

An accompanying effect of eutrophication that is more readily observable in Table 1 is a decrease in silica concentration in Lake Ontario. Some decline in dissolved siHca apparendy has occurred in all of the lakes except Lake Superior. This decline is brought about by the growth of diatoms, a species of aquatic microorganisms in the upper layers of lake water that is widespread in aU types of water impoundments where the water is clear and exposed to the sun. The siUca is used by these microorganisms to form their skeletons and is later precipitated and becomes part of the bed sediment. 

CP historical profiles in sediment. The spatial trends in sediments discussed above are confounded by varying rates of sedimentation so that some samples may represent the entire history of deposition of CPs while others may be recent deposition only. This is particularly clear in the study by Marvin et al. [39] in Lake Ontario. Sediment cores, dated using Pb and Cs, can be used to derive fluxes (ng m year ) and are thus more appropriate for comparing locations and... 

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