what causes a lake to turn over what causes a lake

Causes & Effects of Fall Lake Turnover

Water is quite possibly the most fascinating substance on earth. This is true for a number of reasons, not the least of which is that without water, life as we know it would non exist.

In terms of humans, I recently heard of a new way to calculate how much water ane should consume each day: Take one's body weight in pounds and divide it by two, and that is the number of ounces of water required daily! I am unaware of the requirements for other warm-blooded beast forms, simply I do know that the cold-blooded species so cherished by sports enthusiasts -- fish like walleye, bass, northern pike and musky -- require a lot of water: fresh, clean and oxygen-laden H_iiO in order to survive.

And a unproblematic procedure referred to as lake turnover plays a very disquisitional role in that survival process. Did I say simple? Well... it is, then over again information technology isn't. But I'll try to describe the process in every bit simple and not-technical a way every bit possible.

Water is fascinating, for a number of reasons. I of the more than interesting reasons is due to a water molecule's amazing structure - its chemical science if you volition. In nature, estrus and cold change the concrete properties of all substances in predictable ways.

In general, as things get colder, they contract and become more dense/heavier; as they become warmer, they expand and become less dense/lighter. This chief holds for solids, liquids and gases. Able to exist in all iii forms, water, as a liquid, contracts and becomes more dumbo as it gets colder... at least to a point.

And that bespeak is where the oddity owing to water'south special chemical science comes into play, the one that keeps your favorite lake -- and your favorite gamefish -- healthy and happy.

Something strange and wonderful happens when water reaches a temperature of approximately 39 degrees Fahrenheit (xl Celsius). Well, it is wonderful for lakes and the life in them, not so for the roads on which we drive -- more than on that afterwards.

In any example, as water cools to that temperature, it does, as predicted, contract and become more dense, ultimately sinking to the bottom of the lake and pushing the water information technology has displaced to the surface, where it as well can absurd. With continued cooling at the surface, the decreasing temperature should (or and then it would seem) eventually cause all the h2o to eventually freeze solid and sink to the bottom... significant that the lake would freeze from the lesser up -- eventually destroying all life beneath the waves.

Why and so does this not happen? The chemical science of the water molecule dictates that at 39 degrees (39.20 to be precise) Fahrenheit, water actually expands and becomes less dense, assuasive it to float to a higher place the warmer water! The water that cools beneath that temperature, to 32 degrees, freezes and stays on the acme, effectively capping the lake. It besides stops further energy loss from the lake. Everything below the surface of the ice never gets any colder than 39 degrees Fahrenheit.

And so how does all of this relate to lake turnover (which by the way can actually take place once or several times per season, depending on many boosted factors)? Let's first consider the autumn turnover.

Starting in the bound and over the course of the summer, surface waters absorb a lot of the dominicus's energy and can heat extensively, causing them to become quite buoyant. Winds and storms tin cause some mixing and practise add some oxygen; atmospheric oxygen is added by the air-water interaction to the oxygen produced within the water by aquatic plants.

Merely there is besides much difference in temperature between the surface water and that at depth to let for complete mixing of all the water in the lake. Considering of the density-temperature relationship, many lakes in temperate climates tend to stratify, that is, they separate into distinct layers.

The middle layer, known equally the thermocline, acts as an constructive bulwark to whatever mixing of the deeper waters. Toward the cease of summer, the deep water becomes quite depleted of oxygen because no mixing has taken place.

As the days get shorter and cooler, and free energy is transported away from and out of the lake, mixing becomes easier. At about 50 degrees, the cooler water (with a higher oxygen content) at the surface begins to sink into and through the thermocline, forcing warmer and less dense water to the surface, eventually erasing the temperature stratification built up over the summer.

At some point, the bulk of the water in the lake reaches an approximately compatible temperature. Now, storms and sustained loftier winds can begin to perform the task of overturning and mixing all of the water in the lake -- referred to as autumn turnover .

The deep water contains an abundance of decaying matter and sulfurous gases; when information technology reaches the surface, it produces a telltale odour that indicates the process has begun. Eventually the turnover mixes fresh oxygen into the entire lake mass, replenishing the deep waters with the life-giving stuff and cleansing the sulfurous fumes from the h2o, assuasive fish to return to the depths where they will spend the winter months.

Just an extra note, since this page seems to get a lot of views, especially in the autumn of the twelvemonth. Non all lakes experience turnover to the aforementioned extent or in the exact same way, due to things like depth, lesser structure and size.

Very shallow lakes -- with piffling or no thermocline -- may experience little if whatsoever noticeable turnover. Large and very deep lakes will plainly take longer for the phenomenon to exist completed.

Equally winter approaches, the h2o that has now reached 39 degrees sinks to the lesser, assuasive colder and less dense, buoyant water to remain at the surface to freeze. The ice thickens because it is not a skillful insulator; water in contact with the underside of the water ice cools further and freezes, adding to the surface layer.

A stratification similar to that of the summer months will occur in the water column during the wintertime months, but non to every bit smashing an extent. With the advent of spring, the warming/melting of the water ice layer at the surface and the much smaller temperature differences in the h2o column, winds and storms are able to create a spring turnover with trivial difficulty.

As the waters continue to warm, stratification begins once more and the endless bicycle continues. Mother Nature has performed her timeless and never-ending job, adding additional life-giving oxygen to the lake and readying information technology for the onslaught of another season of fishermen.

Oh, yes -- remember the roads I mentioned earlier? Well, the same temperature and density changes that cause the expansion and contraction of water as information technology freezes and thaws -- office of the natural and positive process for lakes -- works the same way for the water that seeps into and under the roads on which we drive.

As it freezes and thaws, expanding and contracting as the temperature continually moves upwardly and down past 39 degrees, ultimately causes the potholes and cracks that are headaches for drivers and road crews alike.

Just recall to accept that bottle of beer out of the freezer before it explodes!

Every bit always, I hope to run into you On the Lake!

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Source: https://onthelake.net/fishing/turnover.htm

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