What is water quality ? Water details part-2
What is water quality
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The need for water for aquatic animals
Among the thousands of aquatic animals, our most well-known aquatic animal is fish. What happens if you leave the fish out of the water? You have all seen the fish die.
Why die? Because just as we cannot live without air or oxygen, we die of suffocation, as is the case with fish. Fish take in oxygen through the gills and the gills are made in such a way that it can take oxygen only from water, not from air. If there was no water, no fish could survive.
Not only fish, but all the animals that breathe by taking oxygen through the gills could not survive. As a result, the environment would be threatened and it would be difficult for us to survive. You know from previous content (What is food and what is nutrition) that protein is an essential element for our growth.
About 80% of our essential protein comes from fish. So without water we would not get the protein we need, so our physical growth and any other biological processes would not work properly.
What is water quality
Water standards
Water is a very valuable natural resource. In the previous discussion we have seen that river water is a very important part of our environment, it is a habitat for aquatic plants and animals. Not only that, this water is used for dancing in agriculture.
Similarly, ship’s sailors, who make a living by launching, boating or tuller, all process and drink river water or seawater and use it for other purposes. Therefore, if the water does not maintain a certain quality, it will be detrimental to biodiversity or the environment, and its use will be disrupted. Let’s take a look at water standards: The quality of the water depends on what we use it for. First we need to know what the standards of rivers, canals and seawater should be.
What is water quality
Color and Taste:
You know that pure water is colorless and tasteless, so it is better for the animals and plants living in the water to have water in rivers, canals, etc., colorless and tasteless.
The amount of whey
The amount of whey turbid water can cause serious damage to aquatic animals and plants. This is because when the water is turbid, sunlight cannot reach the plants under the water.
As a result photosynthesis is disrupted. On the one hand, it interferes with the production of food by aquatic plants, which slows down their growth, and on the other hand, the oxygen produced by photosynthesis is shut down. When water is turbid, fish or other animals cannot collect food properly.
The main cause of water turbidity is natural causes, i.e. river erosion, silt, etc. Water is also exposed to man-made causes, such as the presence of oils, greases, and other insoluble substances. As a result, navigability is reduced and navigation becomes difficult. You must have seen the news of launch, steamer getting stuck in the submarine in the newspaper or on television. Why are these stuck? The main reason is the decrease in navigability.
What is water quality
Presence of radioactive substances
The presence of radioactive substances in river water can cause cancer-like diseases in aquatic plants and animals. Therefore, river water should be completely radioactive.
Garbage
All natural water including rivers must be free from dirt and garbage. Because all kinds of life-destroying germs are created from garbage.
Dissolved Oxygen
Just as we need oxygen to breathe, so do aquatic animals need oxygen to breathe. Where do they get this oxygen from? They get this oxygen from the dissolved oxygen in the water. If for some reason this oxygen falls below a certain level, then aquatic animals have problems. If there is no dissolved oxygen in the water, other animals, including fish, cannot survive. Aquatic animals need at least 5 mg of oxygen in 1 liter of water to survive.
What is water quality
Temperature
Temperature is another important criterion of water. When the water temperature rises above normal, on the one hand the dissolved oxygen decreases; on the other hand all the physiological functions starting from the reproduction of aquatic animals are also affected.
What is water quality
Ph
A pH is a quantity that indicates that water or any other aqueous solution is acidic, alkaline or neutral. The pH is 7 when neutral, less than 7 if it is acidic, and more than 7 if it is alkaline. As the amount of acid increases, the value of pH decreases, on the other hand, as the amount of alkali increases, the value of pH also increases.
The pH value is very important for rivers, canals, etc. Usually river water is alkaline. Studies have shown that if the pH of river water is between 6-7, it does not cause any difficulty for the survival of aquatic plants or animals.
However, if the pH level drops or rises above this, then the water is severely damaged by other aquatic animals and plants, including fish. Fish eggs, fingerlings cannot survive if the pH of the water is too low or too high. When the amount of acid in the water is too high, i.e. the pH is too low, calcium and other important minerals are released from the body of the aquatic animal, which makes the fish easily infected.
What is water quality
Salinity
Do you know why our national fish hilsa comes in fresh water while laying eggs? Although hilsa is a marine fish, but it comes into the freshwater at the time of breeding, that is, during the laying of eggs, because the sea water contains a lot of salt, which destroys the eggs, so that the eggs can no longer produce good.
Therefore, according to the rules of nature, when it is time for hilsa fish to lay eggs, it comes to fresh water. However, this does not apply to all fish. Some fish and aquatic animals can only breed in salt water.
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