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These two figures help
explain what stratification and turnover are. In the summer and winter,
lakes tend to be stratified, where the surface water is a different
temperature than the bottom water. Because of that, the lake does not mix
completely. In fall and spring, the surface waters either cool off or warm
up until they are about the same temperature as the bottom waters. This
allows for turnover or mixing of the entire water column. . Turnover is
indicated by a straight temperature graph because temperature is fairly
uniform. A curved temperature graph, like we found (point) indicates
stratification Throughout the summer, Long Pond North was stratified. This
lack of mixing kept bottom dissolved oxygen concentrations low and bottom
phosphorus levels high. The high bottom phosphorus levels resulted from the
anoxia-driven phosphorus release from the sediments.
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