What is the reason for the decrease in oxygen content in water after eutrophication???

Algae. Reproduction and reproduction are too fast, covering the water surface, resulting in oxygen not being able to dissolve in water, and the original oxygen in the water is absorbed by the water organisms, resulting in a decrease in the oxygen content of the water Satisfied Thank you.

Eutrophication will affect the water quality of the water body, causing the water to reduce its transparency, making it difficult for sunlight to penetrate the water layer, thus affecting the photosynthesis of plants in the water, and may cause a supersaturated state of dissolved oxygen. The oversaturation of dissolved oxygen and the low amount of dissolved oxygen in the water are harmful to aquatic animals and cause a large number of fish deaths. At the same time, because of the eutrophication of the water body, a large number of algae with cyanobacteria and green algae as the dominant species grow on the surface of the water body, forming a layer of "green scum", resulting in the harmful gases produced by the decomposition of organic matter accumulated at the bottom under anaerobic conditions and the biotoxins produced by some plankton will also harm fish.

Because eutrophication water contains nitrate and nitrite, humans and animals will also be poisoned and sick if they drink water with these substances exceeding a certain standard for a long time.

In surface freshwater systems, phosphate is often the limiting factor for plant growth, while in seawater systems, ammonia nitrogen and nitrate are often the limiting factors for plant growth and overall production. For example, in normal freshwater systems, phosphorus content is usually limited, so increasing phosphate can lead to overgrowth of plants, while in marine systems, phosphorus is not lacking, but nitrogen content is limited, so the addition of nitrogen-containing pollutants will eliminate this limiting factor, resulting in overgrowth of plants. Domestic sewage, industrial wastewater such as fertilizers and food, as well as farmland drainage, contain large amounts of nitrogen, phosphorus and other inorganic salts.

When these effluents are received by natural water bodies, the nutrients in the water increase, which leads to the vigorous growth of autotrophic organisms, especially the number of cyanobacteria and red algae in which the number of individuals increases, while the number of other algae gradually decreases. The algae in the water body were originally dominated by diatoms and green algae, and the abundance of cyanobacteria was a sign of eutrophication, and with the development of eutrophication, it finally became dominated by cyanobacteria. Algae multiply rapidly and have a short growth cycle.

After the death of algae and other plankton, they are decomposed by aerobic microorganisms and continuously consume dissolved oxygen in the water, or they are decomposed by anaerobic microorganisms to continuously produce gases such as hydrogen sulfide, which deteriorates the water quality in two ways, causing a large number of fish and other aquatic organisms to die. In the process of decay, algae and other plankton residues release large amounts of nutrients such as nitrogen and phosphorus into the water for the use of new generations of algae and other organisms. Therefore, the eutrophicated water body, even if the external nutrients are cut off, it is difficult for the water body to purify itself and return to its normal state.

There are two main causes of eutrophication in water bodies:

1. Eutrophication caused by water sources. For example, the source and channel of aquaculture water sources include domestic sewage outlets, factory tail water outlets, etc. In particular, the water is rich in nitrogen, phosphorus and other substances, which is easy to cause eutrophication of water bodies.

2. Eutrophication caused by the filing of products. When breeding, we will fertilize, bait, medicine, these things contain a lot of nutrients, especially the excessive use of inorganic fertilizer and a large amount of surplus feed, easy to cause sludge, water and other nutrients, resulting in water pollution.

Eutrophication refers to the phenomenon of water pollution caused by excessive nutrient content such as N and P in water bodies.

Its essence is that the input and output of nutrients are out of balance, which leads to the imbalance of species distribution in the aquatic ecosystem, and the crazy growth of a single species, which destroys the pure flow of matter and energy in the system, and gradually extinguishes the entire aquatic ecosystem.

The reason for eutrophication of water bodies is that excess nitrogen, phosphorus and other nutrients in water bodies mainly come from untreated or incompletely treated industrial wastewater and domestic sewage, organic waste and livestock and poultry manure, as well as agricultural fertilizers, the largest of which is a large amount of chemical fertilizers applied on farmland.

The reason for eutrophication of water bodies is that the input and output of nutrients are out of balance, which leads to the imbalance of species distribution in the aquatic ecosystem, and the growth of a single species, which destroys the flow of matter and energy in the system, and gradually extinguishes the entire aquatic ecosystem.

Water eutrophication refers to the phenomenon that under the influence of human activities, a large number of nutrients such as nitrogen and phosphorus required by organisms enter slow flowing water bodies such as lakes, rivers and lakes, bays, etc., causing the rapid reproduction of algae and other plankton, the decline of dissolved oxygen in water bodies, the deterioration of water quality, and the mass death of fish and other organisms. Under natural conditions, lakes also transition from eutrophication to eutrophication, albeit very slowly.

However, eutrophication of water bodies caused by the artificial discharge of industrial wastewater and domestic sewage containing nutrients can occur in a short period of time. When eutrophication occurs in a water body, planktonic algae bloom in large numbers, forming a bloom (a natural ecological phenomenon in which algae bloom in freshwater bodies). Due to the different colors of the dominant planktonic algae, the water surface tends to appear blue, red, brown, milky white, etc.

This phenomenon in the ocean is called red tide or red tide.

Governance Implications:

1. The treatment and restoration of eutrophicated rivers and lakes is an urgent need for social and economic development, urban landscape and ecological environment construction, and has dual economic and environmental benefits.

2. Significantly improve the treatment effect of eutrophicated rivers and lakes, greatly shorten the treatment cycle, and effectively reduce the treatment cost.

3. Restore the function of water bodies and effectively alleviate the problem of serious shortage of water resources in China.

4. Improve the living environment of residents and improve the quality of life of the people.

The above content refers to Encyclopedia - Water Eutrophication.

Water eutrophication may be caused by natural changes, most of the lakes are from eutrophication, after hundreds of years of change to eutrophication, absorb nitrogen and phosphorus elements in rainwater, soil erosion, leaching, and provide nutrients for phytoplankton and aquatic animals. It may also be caused by the random discharge of industrial wastewater, which contains a large amount of nitrogen and phosphorus in the wastewater of the steel, chemical and paper industries. It may also be caused by untreated domestic sewage, and the detergent residue in the sewage will contain nitrogen and phosphorus, resulting in eutrophication of the water body.

Eutrophication of water bodies may be caused by natural changes, because lakes and rivers are from eutrophication, slowly changing, in the process of natural activities, lakes and rivers will absorb nitrogen and phosphorus elements in rainfall, and the soil in the water will also be corroded, providing sufficient nutrients for phytoplankton and animals.

Water eutrophication may also be caused by the random discharge of industrial wastewater, due to the wastewater generated in the industrial production process, which contains a large amount of nitrogen and phosphorus, before being discharged into rivers and lakes, the treatment is not complete, and the content of nitrogen and phosphorus in the wastewater is still relatively high, and it continues to form accumulation in the water body.

Water eutrophication may also be caused by excessive discharge of domestic sewage, due to the large discharge of domestic sewage, a lot of sewage is directly discharged without treatment, and most of the domestic sewage is the residue of detergent, which contains a large amount of nitrogen and phosphorus, resulting in eutrophication of the water body.

Water eutrophication may be caused by the excessive use of chemical fertilizers and pesticides, due to the large use of chemical fertilizers and pesticides, crops can not be completely absorbed, a large amount of organic matter accumulates in the soil, causing pollution of the soil environment, and eventually decay, fermentation and infiltration into the groundwater, resulting in the pollution of the water body.

a.All stupid ruin balls warm.

b.The effluent produced by phosphorus-containing detergents is discharged without treatment.

c.Large amounts of municipal wastewater.

d.Production and use of large quantities of nitrogen-containing and phosphate-containing fertilizers.

Positive with the answer: BCD

Water eutrophication mainly refers to the increase of nitrogen and phosphorus content in water.

Its essence is that the input and output of nutrients are out of balance, which leads to the imbalance of species distribution in the aquatic ecosystem, and the crazy growth of a single species, which destroys the flow of matter and energy in the system, and gradually extinguishes the entire aquatic ecosystem.

Eutrophication not only affects the use function of water bodies, but also endangers human health, and is generally considered to be inferior water bodies. Its impact on the environment is mainly reflected in:

1) The overbloom of algae in eutrophicated water bodies makes the water mildew and foul, reducing the quality of the water.

2) The dense algae on the surface make it difficult for sunlight to penetrate into the deep lake, and the photosynthesis of the deep water body is weakened, so that the dissolved oxygen is reduced. At the same time, the decay and decomposition of algae after death accelerates the consumption rate of dissolved oxygen in the water body, and the lack of oxygen in the water body becomes inevitable.

(3) The normal ecological balance of eutrophicated water bodies was disturbed, and the number of biological populations fluctuated violently, which led to the reduction of the stability and diversity of aquatic organisms and destroyed the ecological balance of water bodies.