What is the concept of eutrophication in water bodies?

Eutrophication refers to the phenomenon that under the influence of human activities, a large amount of nutrients such as nitrogen and phosphorus required by organisms enter slow flowing water bodies such as lakes, estuaries, and bays, causing the rapid reproduction of algae and other plankton, the decline of dissolved oxygen in water, 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 and blooms. 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.

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Water eutrophication refers to the phenomenon that under the influence of human activities, a large amount of nutrients such as nitrogen and phosphorus required by organisms enter slow flowing water bodies such as lakes, estuaries, and bays, 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, the lake transitions from a flat trophic lake to a eutrophic lake, and then to a swamp and land, as the river entrainment impact and aquatic debris continue to settle and silt at the bottom of the lake.

Eutrophication of water bodiesThe hazards are:

1. ImpactPhotosynthesisEutrophication of water bodies reduces the transparency of water, which makes it difficult for sunlight to penetrate the water layer, which affects the photosynthesis of plants in the water and the release of oxygen.

2. Endanger aquatic animals. After the "eutrophication" of the water body, the organic matter accumulated at the bottom layer decomposes under anaerobic conditions, and produces harmful gases, as well as some plankton.

The biotoxins produced can also harm aquatic animals.

3. Harmful to the human body. "Eutrophication" water contains nitrites.

and nitrate, humans and animals drinking water with these substances above a certain standard for a long time will be poisoned and carcinogenic.

4. DestructionBiodiversity"Eutrophication" of water bodies often leads to the disorder of aquatic ecosystems, the reduction of aquatic species, and the destruction of diversity.

Prevention and control methods of water eutrophication:

1.Chemical method: The use of chemical reagents that condense sedimentation silver to kill algae plants in the water body.

2.Biological methods: reduce nitrogen and phosphorus in water by cultivating aquatic plants.

content. 3.Artificial method: Excavate the sediment and sediment material in the water world through artificial methods, add oxygen to the water, and introduce water that does not contain nitrogen and phosphorus or has a low content.

Eutrophication is a kind of nitrogen, phosphorus and other plant dus

Water caused by excessive nutrient content.

DAO quality pollution phenomenon. In since.

Under specific conditions, the lake will transition from a flat trophic lake to a eutrophic lake, and then to a swamp and land, which is an extremely slow process as the river entrainment alluvium and aquatic debris continue to settle and silt at the bottom of the lake.

However, due to human activities, after a large amount of industrial wastewater and domestic sewage and plant nutrients in farmland runoff are discharged into lakes, reservoirs, estuaries, bays and other slow-flowing water bodies, aquatic organisms, especially algae, will multiply in large quantities, changing the number of biomass species and destroying the ecological balance of water bodies.

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Analysis: Due to the discharge of excess nutrients (mainly referring to nitrogen, phosphorus, etc.) in natural water bodies, various aquatic organisms and plants are abnormally reproduced and the growth of raw oaks, which is called eutrophication.

These excess nutrients mainly come from farmland fertilization, agricultural waste, municipal domestic sewage and some industrial wastewater.

The nitrogen in sewage is divided into two categories: organic nitrogen and inorganic nitrogen, the former is nitrogen-containing compounds, such as proteins, peptides, amino acids and urea, etc., and the latter refers to ammonia nitrogen and nitrite nitrogen, most of which come directly from sewage, but some of them are formed by microbial decomposition and transformation.

Urban domestic sewage is rich in nitrogen and phosphorus, such as human excretion contains a certain amount of nitrogen, and the use of phosphorus-containing detergents contains a large amount of phosphorus. In addition, such as the mining of apatite, saltpeter, guano layer, and the large use of chemical fertilizers, it is also the first time that nutrients such as nitrogen and phosphorus enter the water body.

Generally speaking, if the total phosphorus and inorganic nitrogen are 20 milligrams and 300 milligrams of cubic meters, respectively, the water body can be considered to be in a state of eutrophication. The key to the problem of eutrophication is not the concentration of nutrients in the old shed, but the load of nutrients that continuously flow into the water body, so the degree of eutrophication of the water body cannot be determined completely according to the concentration of nutrients in the water. There are two ways to express the ultimate loading of nutrients in a water body:

Loading per unit volume: grams (cubic meters.) years).

Load per unit area: grams (sqm.) years).

According to the study, if most of the phosphorus entering the water body flows in the form of biological metabolism, the critical load between the oligotrophic lake and the eutrophication lake is: total phosphorus is g (square meters). years), the total nitrogen is 5 10 g (m².

years).In short, the role of phosphorus is much greater than that of nitrogen, and eutrophication can be caused when the content of phosphorus is not very high.

In the normal cycle of natural materials, lakes will develop from nutrient lakes to eutrophic lakes, and further develop into swamps and dry lands, but this process takes a long time, tens of thousands or even hundreds of thousands of years under natural conditions. However, eutrophication due to water pollution will greatly facilitate this process. If plant nutrients such as nitrogen and phosphorus enter slow-flowing water bodies such as lakes, reservoirs and bays in large quantities and continuously, they will promote the activity of various aquatic organisms, * They bloom abnormally (mainly algae), which can lead to a series of serious consequences:

1) The space occupied by algae in the water body is getting larger and larger, so that the space for fish activities is getting smaller and smaller; Dead algae will be deposited at the bottom of the pond.

2) The number of algae gradually decreased, and changed from diatoms and green algae to cyanobacteria, and many species of cyanobacteria have colloidal membranes, which are not suitable for fish bait, and some of them are toxic.

3) The excessive growth and reproduction of algae will cause a sharp change in dissolved oxygen in the water, and the respiration of algae and the decomposition of dead algae consume a large amount of oxygen, which may make the water body in a serious hypoxic state for a certain period of time, which seriously affects the survival of fish.

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 flow of matter and energy in the system, and gradually extinguishes the entire aquatic ecosystem.

Excess nitrogen, phosphorus and other nutrients in the water body 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.

Causes of eutrophication of water bodies].

Water eutrophication is a type of organic pollution that deteriorates water quality due to excessive nutrients such as nitrogen and phosphorus entering natural water bodies. In general, about half of the nitrogen fertilizer applied to farmland is not used and flows into groundwater or ponds and lakes, and a large amount of domestic sewage often overfertilizes the water body. Excessive nutrients promote the proliferation of phytoplankton in the waters, such as cyanobacteria, diatoms and aquatic plants, and sometimes the entire water surface is covered by algae to form a "splash", and the algae are deposited at the bottom of the water after death, and the microbial decomposition consumes a large amount of dissolved oxygen, leading to the death of a large number of fish due to lack of oxygen.

Eutrophication of water bodies accelerates the decline of lakes and turns them into swamps.

1. The color of the water body is abnormal;

2. Elevated pH;

3. Reduced transparency;

4. Dissolved oxygen increases significantly during the day and decreases significantly at night.