88 kinds of freshwater shellfish in Poyang Lake Area shine out the "Eighteen Martial Arts" to purify the water body

"Cool wind to, white dew to fall, cold cicadas", the "white dew" in the 24 solar terms has passed, indicating that mid-autumn is coming, and the cold air begins to gradually go south, which can be described as "white dew autumn wind night, a cool night". For migratory bird lovers, this also means that the winter migratory birds of Poyang Lake will be available in the near future.

Poyang Lake is known as a "paradise for migratory birds", and a large number of birds come here every year to overwinter, including rare and endangered birds such as white-headed cranes and black cranes. In fact, Poyang Lake is one of the most biodiverse areas in China's wetlands, and its wetlands are inhabited by plankton, insects, molluscs and various fish and birds.

The benthic animals in the lake are an important part of the ecosystem of Poyang Lake, and these aquatic animal groups that live at the bottom of the water body all or most of the time are not only the main food source for migratory birds and fish in the lake area, but also the indicator organisms for the monitoring of the environmental quality of the lake body, and can also purify the water body.

There are about 106 species of benthic animals in Poyang Lake

Benthic animals are a long-term animal community that lives at the bottom of water bodies and is widely distributed in rivers, lakes and seas. This community is a vast ecological group that includes a variety of animal classes. Taking the freshwater environment as an example, our common shrimp, crabs, shellfish and aquatic insects, as well as freshwater sponges, hydras, nematodes, feather mosses, etc., which are not familiar to most people, belong to the benthic animal family.

Poyang Lake is the largest freshwater lake in China and has rich benthic animal resources. The reporter learned from the Poyang Lake Wetland Management Bureau that there are about 106 species of benthic animals in Poyang Lake, including 87 species of molluscs, 17 species of aquatic insects in 5 orders and 8 families, and 12 species of oligochaetes.

In the benthic community of Poyang Lake, the number of molluscs is absolutely dominant. In the animal kingdom, the mollusc phylum is the second gate after the arthropod phylum, which is divided into 8 classes, with more than 100,000 species, from mountains, rivers, lakes and seas to various temperature zones. Most molluscs are covered with a variety of shells, such as snails, snails, abalone, oysters, etc., which are members of the mollusk phylum. Generally speaking, people call mollusks with shells outside the body shells shells shells.

There are 88 species of freshwater shellfish in poyang lake area

The benthic animals of Poyang Lake mainly include freshwater shellfish, aquatic insects, oligochaetes and so on. Wu Xiaoping, director of the Department of Biotechnology at the School of Life Science and Food Engineering of Nanchang University, an expert in the study of freshwater shellfish, told reporters that freshwater shellfish are the largest population in Poyang Lake.

Freshwater shellfish, as the name suggests, are mollusks with shells that live in freshwater waters, mainly including bivalves and gastropods. Bivalves refer to molluscs Phylum Bivalve animals, mainly referring to mussels; gastropods and bivalves belong to the same phylum, mainly referring to snails.

It is understood that there are 88 species of freshwater shellfish in Poyang Lake, 8 families, 16 genera and 41 species of gastropods, and 4 families, 17 genera and 47 species of bivalves. Among them, 40 species of bivalve species are endemic to China. Many of the shellfish in Poyang Lake are rare species and are difficult to find at present, while the rest of the shellfish are more numerous and distributed throughout the lake area.

Poyang Lake smoke waves, the lake area water environment is complex, underwater life of many freshwater mussels, such as dome bead mussels, lake swamp clams, sword-shaped spear mussels, spinnaker mussels, etc., these mussels in the lake area is widely distributed and more numerous, of which the largest number of large fen lakes. Commonly known as the freshwater pearl mussel, the spinnaker mussel produces pearls with a strong sense of luster and a thick nacre layer, and is often used as a mussel species for cultivating natural and artificial pearls. The lake area's clam is also an important breeding mussel.

Among the benthic animals in Poyang Lake, snails are the most common, not only in number, but also in many types, mainly including Chinese round field snails, rust ring snails, Chinese swamp snails, large swamp snails and so on. These snails are more distributed in waters such as Mussel Lake.

Benthic animals are indicator organisms of the aquatic environment

Benthic animals live aptly as they are, mostly buried in underwater sediment, while others attach to hard substrates such as underwater rocks, or on the surface of aquatic plants and other benthic animals. They feed on surface plankton and sediment, and recuperation takes place underwater.

Because of this special habit, benthic animals have the characteristics of weak migration ability and strong regionality, and most benthic animals respond to changes in the environment of their habitats. Therefore, when the surrounding water environment changes, the survival of benthic animals will be affected to a certain extent. Wu Xiaoping said that some benthic animals are more sensitive to eutrophication of water bodies, some are more sensitive to water pollution, some are more sensitive to low-oxygen environments, and there are more snails with strong pollution resistance.

This indicator organism needs to survive under certain water quality conditions and is sensitive to changes in the quality of the water environment, in addition to benthic animals, plankton, oligochae, chlorella, etc. can also be used as indicator organisms.

As a class of macrobenthic animals, shellfish are often used as water pollution indicator organisms because of their unique filter feeding methods and their strong bioinvaluation effects on heavy metals, persistent toxic organic pollutants, nutrients, etc., especially bivalves.

Freshwater shellfish purify water bodies

Benthic animals are important biological groups in freshwater ecosystems and play an important role in freshwater ecosystems. In addition, benthic animals also have an unknown "function", that is, to purify the water environment, in this regard, shellfish can be described as the leader of benthic animals.

According to Wu Xiaoping, because shellfish are filter-eating animals, they can filter water bodies by ingesting plankton and some particles and debris in the water. In addition, the shellfish body can also secrete mucus, precipitating suspended solids in the water body, so as to achieve the effect of purifying the water body. Take the pleated crown mussels in Poyang Lake as an example, they inhabit the silt of the water body, mainly feeding on tiny organisms and organic debris in the water, like filters, cleaning up impurities in the lake.

In fact, in addition to benthic animals, many organisms in Poyang Lake can purify water bodies. The lake's abundant fish resources not only provide food for migratory birds, but also clean up plankton, food debris, rotten organisms, etc. in the lake, thus playing a role in improving water quality. At the same time, wetland plants in Poyang Lake also play an important role in the material production, nutrient cycling and degradation of pollutants in the wetland ecosystem.

Freshwater shellfish are a food source for migratory birds

Poyang Lake is China's largest freshwater lake, its area is 3960 square kilometers when the normal water level, Poyang Lake National Nature Reserve Management Bureau Great Lake Pond Protection and Management Station Director Gong Leiqiang told reporters that every winter, there are about 330 species, nearly a million wetland migratory bird population to Poyang Lake for wintering, "when flying do not see the clouds and the moon, when the sunset does not see the lake grass."

It is the world's largest bird sanctuary to protect rare migratory birds, such as white cranes. The reserve is located in the northwest corner of Poyang Lake, with 9 lakes, including Shahu Lake, Dafen Lake, Benghu Lake, Zhushi Lake, Meixi Lake, Elephant Lake, Dahu Pond, Changhu Pond and Zhonghu Pond, with a total area of 224 square kilometers, which is a veritable "migratory bird paradise".

Among the more than 300 species of birds in Poyang Lake, there are many national key protected animals. It is not only the world's most important wintering ground for white cranes, eastern white storks and wild geese, but also large bustards, black storks, cygnets, white-fronted geese and white spoonbills waiting for birds to overwinter here. Wintering migratory birds in the lake area are mainly concentrated in the 9 lakes of the reserve, shellfish are distributed in the lake area, in deep water, shallow water and some lakeside mud pools can be seen, especially in the mussel lake and dafen lake where migratory birds are widely concentrated, there are a large number of mussels and snails.

Gong Leiqiang introduced that these wintering migratory birds have a complex diet, including carnivorous birds such as oriental white storks that feed on small fish and shrimp and shellfish, omnivorous birds such as swans, and vegetarian birds such as white cranes that eat aquatic roots. The geese and ducks that are more distributed in the Great Lakes pond are a typical omnivorous bird. There is also a spotted autumn sand duck in Poyang Lake, known as the "panda bird", and the main food source of this rare and endangered species is shellfish.

Shellfish occupy an important position in the diet of migratory birds, and shellfish are also the main food of fish in the lake, so it can be seen that ensuring the number of shellfish populations in Poyang Lake is of great significance for the protection of migratory birds in Poyang Lake and the development of fisheries and the ecological environment of the lake area. Once the survival of shellfish in Poyang Lake is threatened, other aquatic biological resources are bound to be seriously affected. Therefore, protecting benthic animals such as shellfish is equivalent to protecting the vibrant Poyang Lake.