Has Patoka turned over

[junior]

Fishing is tuff enough,,Now the lakes are starting to turn over, Any info on Patoka?

[GeoFisher]

for a lake this time of year to turn over, the water has to COOL really quickly on top...............don't believe it is turning over but might be having some stratification............Moose, help me out here.

I think as summer pushes in, most lakes develop 3 distinct layers, and upper layer, a lower layer, and the the MONEY SPOT.......where the thermocline is..........

Later,

Geo

[Moose1am]

Geofisher:
You are doing just fine mate.

Remember guys that during the winter months the lake has mixed and will be the same temperature from top to bottom. Well there will be a slight temperature difference in that the very bottom of the lake will have the most dense water. Water is more dense at 4 Deg C or about 38 or 39 deg F. Water at 3 deg C is lighter than water at 4 deg C. and Ice floats because it's lighter than the water. So at zero deg C or 32 deg F and below the water turns into ice and will float to the top.

This physical property of water prevents lake and river from freezing from the bottom to the top of the lake. That would kill all the fish in a lake if that were to happen. It's things like that that make me want to believe in a god.

Anyway lets go though this and see what happens to a body of water going from cold months to the spring time.

First off I have read about lakes turning over in the spring time but I never really understood what that meant. I fully understand the lake turning over in the fall but this spring turnover has me puzzled

Lets go from Ice on the water to ice out and then spring and see what is meant by a spring turnover.

When there is ice on a lake the lake is truly stratified. The Ice is one layer and then there is water right under the ice that's very cold. Then there is a layer of water on the bottom that's right at 4 deg C.

OK as the ice begins to melt the surface waters are at zero deg C still. As they warm up from zero deg C to 4 deg C the lake turns over. The lakes waters are no longer stratified by temperature and the entire lake is free to mix from top to bottom.

Now as the lake reaches 5 deg C the surface water begin to heat up and will float above the colder 4 deg C water.

Most heat is obtained from the sunlight so that means that the surface waters have to heat up first. And since warmer water is lighter the cool water the warmer water will float above the colder water.

As the surface waters heat up to 70 deg F or 25 deg c they will stay on top of the bottom waters.

As summer progresses the hottest water will be found laying on the surface. Water below will stay colder. Now the water is layers once again. There is a very high thermal gradient between the top surface water and the bottom waters. This is when you get a thermocline formed in some lakes. The temperature difference is so great that the wind and waves can't break up the thermocline.

Now as fall arrives and the surface water's temperature drops down to the 54's it reaches the same temperature as the lake's bottom waters and the lake turns over. This is the fall turnover. This is were the bottom waters are mixing with the surface waters again.

Hope this helps. It helped me figure out what they mean by the spring turnover.

Ice out up North is an important event for those Northern Guys. You might call that their spring turnover.

But this time of the year in the Midwest we are not really experience any major turn overs that might have a significant effect on the fish.

That's my two cents.

[Stevens]

Great info there, just wondering how much effect does light penetration into the water or vegetation effect a thermocline. And is it true that when a thermocline forms, the fish would prefer to stay 10 feet above it, or would they rather be right above it?

[Moose1am]

The water's clarity has a great deal to do with the depth that the light can penetrate into the water. It probably has a much greater effect on how deep submergent vegetation can grow than on the water's temperature.

But the warming of the water is totally dependent on the sunlight heating the air and water.

Not really sure how the fish relate to the thermocline. Most thermoclines that I have seen while scuba diving in lakes are about 10 to 20 ft down.

I can tell you about one dive I made in a lake that was used for public swimming. I am talking about the old Wes Lake on the NW side of Evansville, IN.

I use to work there as a life guard when I was younger and was good friends with the owners. All the life guards were allowed to swim there after hours. So in the morning before the lake opened to the public I would often get my scuba gear out and go for a dive. The lake is about 5 or 6 acres in size. They had installed concrete docks for diving boards and a big tall trapeze. The docks were build on 25 ft tall concrete columns. There were four columns holding up the Trapeze dock.

One morning I was diving by one of these concrete columns. I held onto one of the docks ladders that was next to the column and was gradually allowing myself to sink down toward the bottom. I had gone down about 10 ft to 15 ft and could see some bass hanging right next to the column. My head was 10 to 15 ft below the surface but my feet were 21 ft beneath the surface and touching the colder water below the thermocline.

When you dive down you can feel the colder water.

I think that anyone that's dove down into a lakes depths knows that you can feel the colder water below. I use to free dive down to the bottom of the lake underneath the trapeze to search for drowning victim.

So this day I found the 1 and 2 lb sized largemouth bass suspended and associating very close to the concrete pillar (vertical Structure). The pillar was about 2ft by 2ft in size.

Now this was in an area of the lake that had the bottom deepened. The clay bottom was dug out to make this area of the lake deep enough to keep people from hitting bottom when the dropped off the trapeze and diving platform. The diving platform was about 4 meters high. At times when I went off the tepees and entered the water just right I could easily reach the bottom of the lake which was around 25 to 30 ft deep at that point.

Most of the other parts of the lake were about 15 ft deep. The lake bottom out in the middle part of the lake was muck. You could be swimming along the bottom out there and not see more than two feet around your face mask. A few times I was scuba diving out in the middle of the lake just exploring the bottom. I didn't see many fish out there. One in a while I would see a small crawdad flipping out of my view and leaving a mud plume behind him. There were a lot of crayfish living out on the bottom of this lake. So the bass had a lot to eat.

I fished this lake from the shore and from a row boat and also from the concrete dock. Once while fishing from the dock in the early spring when the lake was closed I dropped an unweighted small 4" long plastic worm down near the pillar where I had seen the bass suspended. Sure enough I saw a bass come out of the gloom and hit the worm. I could see him opening his mouth and sucking in the small plastic worm. I was not quick enough to set the hook and he spit the hook out fast. It happened so fast. And the worm had not sunk down more that 5 ft.

Not sure what the fish did when there were 2000 people swimming on that lake on the Fourth of July Weekend.

Now I often would walk around that lake in the mornings during the spring time and catch bass on my fly rod. Never did catch anything really big but I did have a lot of fun hooking and releasing a lot of small bass. I caught a lot of bluegills too. The fishing was best on the secluded parts of the lake. I didn't really fish near the swimming areas as I didn't want to have a hook come of and get into that area. I didn't want to be stepping on any fishing hooks when I went swimming,,, if you know what I mean.

All I really know for sure is that most fish that require a lot of oxygen to survive will need to stay above the thermocline in the hot summer months.

The area below the thermocline is called the hypolimnium and it's where all the dead plants and dead animals fall. These organisms are eaten by bacteria. The bacteria are consuming up oxygen in the process of living and after the summer goes along they eventually can deplete the dissolved oxygen in these deeper waters. Since the lake is thermally stratified and not mixing there is no way to get new oxygen into the depths until the lake turns over in the fall. Not until the water from top to bottom reaches the same temperature will the lake become unstable enough to turn over and mix again.

You can go across most lakes and use the depth finder to see how deep the fish are suspended. They may be suspend anywhere above the thermocline but most game fish won't be below the thermocline

Also remember that fish move vertically as the day progresses and turns to night and back again.

Many of the small macrovertibrates are effected by the sunlight. They tend to go deeper during the daylight hours and then rise back up toward the surface at night. Daphnia do this. And those fish that feed on the Daphnia will follow this vertical migration too.

I think that the fish are trying to get below the area where the sunlight penetrates to hide and make it easier for them to catch a meal.

Like a lion hiding in tall grass these game fish like to hide in the shadows. From the depths they can look up and see any small fish above them that are back-lighted by the sunlight.

When you are scuba diving in really clear water you can see what this looks like from a fish's view point. Looking up from the bottom on a sunny day you can see the bright sky above. And this is the reason why the bottom of a fish is light colored. If you are at the surface and looking down at the lake bottom you see a darker colored bottom in some cases. This is why the top (dorsal) part of a fish is darker in color a lot of times. The dark back of the fish blends in with the dark bottom and the light colored top blend in with the brighter sky above the.

[Dakota Kid]

Thank you. Not many people under stand a spring turnover. I grew up in S dak, the ice out IS very important. Wht you just described it, is exactly the way it happens. Warmer water stays on top because it is less dence. Its science.

[slowride]

I think if a resovoir that is large and generates electricity so it has moving water like i.e.kentucky lake they dont have much of a turnover if any. If it gets really dry and the river doesn't feed in water, they will develop a thermocline.

[GeoFisher]

Geofisher:
You are doing just fine mate.

Remember guys that during the winter months the lake has mixed and will be the same temperature from top to bottom. Well there will be a slight temperature difference in that the very bottom of the lake will have the most dense water. Water is more dense at 4 Deg C or about 38 or 39 deg F. Water at 3 deg C is lighter than water at 4 deg C. and Ice floats because it's lighter than the water. So at zero deg C or 32 deg F and below the water turns into ice and will float to the top.

This physical property of water prevents lake and river from freezing from the bottom to the top of the lake. That would kill all the fish in a lake if that were to happen. It's things like that that make me want to believe in a god.

Anyway lets go though this and see what happens to a body of water going from cold months to the spring time.

First off I have read about lakes turning over in the spring time but I never really understood what that meant. I fully understand the lake turning over in the fall but this spring turnover has me puzzled

Lets go from Ice on the water to ice out and then spring and see what is meant by a spring turnover.

When there is ice on a lake the lake is truly stratified. The Ice is one layer and then there is water right under the ice that's very cold. Then there is a layer of water on the bottom that's right at 4 deg C.

OK as the ice begins to melt the surface waters are at zero deg C still. As they warm up from zero deg C to 4 deg C the lake turns over. The lakes waters are no longer stratified by temperature and the entire lake is free to mix from top to bottom.

Now as the lake reaches 5 deg C the surface water begin to heat up and will float above the colder 4 deg C water.

Most heat is obtained from the sunlight so that means that the surface waters have to heat up first. And since warmer water is lighter the cool water the warmer water will float above the colder water.

As the surface waters heat up to 70 deg F or 25 deg c they will stay on top of the bottom waters.

As summer progresses the hottest water will be found laying on the surface. Water below will stay colder. Now the water is layers once again. There is a very high thermal gradient between the top surface water and the bottom waters. This is when you get a thermocline formed in some lakes. The temperature difference is so great that the wind and waves can't break up the thermocline.

Now as fall arrives and the surface water's temperature drops down to the 54's it reaches the same temperature as the lake's bottom waters and the lake turns over. This is the fall turnover. This is were the bottom waters are mixing with the surface waters again.

Hope this helps. It helped me figure out what they mean by the spring turnover.

Ice out up North is an important event for those Northern Guys. You might call that their spring turnover.

But this time of the year in the Midwest we are not really experience any major turn overs that might have a significant effect on the fish.

That's my two cents.

Moose........you ARE the man...........Thanks.

I would have answered sooner, but I was out spanking smallies in Canada, and must have missed this thread........

Later,

Geo

[raporter]

We sure feel sorry you weren't here to answer that one Geo.