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Posts: 1209
| Do lakes turn over at ice out? Thursday night there was three inches of spongy ice on a deep natural lake in ND, the water was clear guessing about 8' of visibility. The ice came out sometime Friday and I was in today (Saturday) and water temps were 41* when it hasn't been that warm air temp in a few days. Visibility wAs approximately 1.5' and heavily stained. |
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Posts: 95
| Yes lake stratification is directly relative to temperature and oxygen is directly relative to temperature in water. because water is most dense at 39 degrees this is when water has the least amount of dissolved oxygen. Water becomes less dense above and below 39 degrees and oxygen increases that's why ice expands and why it floats on the surface typically at ice out most lakes are the same temperature from the top to the bottom although if it is warmer than 39 degrees at the bottom when the ice melts and gets to 39 degrees it is more dense than the water below and will sink to the bottom while the bottom rises. This is called spring turn over and it usually happens a lot faster with help from Wind. |
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Posts: 271
Location: davis,IL | Turnover is a general term that describes a number of things that happen to a body of water. The two temperatures to remember are 39 degrees and 59 degrees. These are the temperatures when turnover begins and ends. Turnover is when the water column starts to mix top to bottom, and an ending to the water stratification (layering). Turnover happens twice a year, in the fall before winter as temperatures decrease. At 59 point something degrees the top layers of water will begin to fall to the bottom and bring leaves and other organic material to the bottom to decompose. In the spring the warmer bottom water will begin to rise bringing the decomposing remnants of organic material up with the warming water ( this is why the water will, under the right conditions, stink in the early spring as the decomposing organic matter rises with the warmer water). Sunlight, lenth of day and wind have definite influences on the speed and intensity of turnover in both seasons. Usually the start of turnover has negative effects on fishing in both seasons because of the organic material and dissolved oxygen levels in the water. So generally speaking, at 59 degrees turnover has finished for the spring and fish will react by seeking the warmer more stable and better oxygenated (usually shallower) water in the spring. In fall the fish will generally do the same thing, only now heading deeper in search of more stable water conditions. Wind is a big factor in oxygenating open water, so that's always a factor in fish behavior and the depth of water they may hold in, in a given moment of time. Whether that be turnover or at anytime during the season. Fish location is usually dictated by available forage and dissolved oxygen and lesser so by temperature and cover. This applies to all seasons.
Edited by muskydope 4/3/2016 3:22 AM
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| esoxriebe - 4/3/2016 2:35 AM Yes lake stratification is directly relative to temperature and oxygen is directly relative to temperature in water. because water is most dense at 39 degrees this is when water has the least amount of dissolved oxygen. Water becomes less dense above and below 39 degrees and oxygen increases that's why ice expands and why it floats on the surface typically at ice out most lakes are the same temperature from the top to the bottom although if it is warmer than 39 degrees at the bottom when the ice melts and gets to 39 degrees it is more dense than the water below and will sink to the bottom while the bottom rises. This is called spring turn over and it usually happens a lot faster with help from Wind. Everything you said about density is correct. However, oxygen solubility INCREASES smoothly as temperature goes down towards the freezing point (0°C). Remember, 0°C = freezing point; 100 °C = boiling point. At 39° F (4° C), dissolved O2 is near maximum:  
Edited by Chemi 4/3/2016 8:11 AM
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Posts: 1209
| thanks. |
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