This article is from the official account: Earth Knowledge Bureau (ID: diqiuzhishiju) , Author: Sue that day, from the title figure: Vision China
Wetland is an important ecological system in nature. If we make an analogy, wetland is to nature as kidney is to human body. It has the functions of conserving water, storing floods and preventing drought, degrading pollution and regulating climate.
Wetlands, an ecosystem that can store large amounts of water
It often plays a sponge-like regulatory role
(Picture: shutter-aabeele)▼
As a transition zone between terrestrial ecosystems and aquatic ecosystems, wetlands are like battlefields of repeated competition between water bodies and land. For example, the mangrove wetlands along the southeast coast of China are coastal wetlands formed by the rise and fall of ocean tides. zone.
Fujian-Xiapu Coastal Mangroves
(Picture: shutter-06photo)▼
The Northeast is the most widely distributed area of wetlands in my country. Of the 44 wetlands listed in the World Wetland List, 12 are in the Northeast. So what caused so many wetlands in the Northeast, and what secrets are hidden in these wetlands?
Northeastern Inner Mongolia-Hulunbuir-Ergun River Wetland
(Picture: shutter-redstone)▼
Hexian Zeguo
China has more than 53.6 million hectares of wetlands, and Heilongjiang is an important province with a large number of wetlands. The distribution of wetlands in Heilongjiang Province is divided by the Xiaoxing’an Mountains in the middle. To the east of Xiaoxing’an Mountains is the wet area of Sanjiang Plain, and to the west is the wet area of Songnen Plain.
Sanjiang Plain to the east, Songnen Plain to the west
In fact, Xiaoxing’anling itself also has a lot of wetlands (mainly marsh wetlands)▼
The reasons for the spread of wetlands in these two areas are the same, first of all lies in the flat terrain. The Songnen Plain and the Sanjiang Plain have small undulations. There is no natural river channel formed in alpine valleys. The rivers flowing on the ground are also difficult to wash out of a fixed channel because of the lack of gravitational potential energy rushing from high to low. Therefore, the diversion of the river and the overflow of the river bank are also occasional events.
Songnen Plain in Woze Thousand Miles
Because of the flat terrain, the river here seems a bit “random”
(Picture: hu rained over the sky / Mapworm Creative)▼
A strange lake on both sides of the river is common in the Northeast Plain. They are close to the river but not connected, and they often exhibit a strange O shape.
This kind of lake is called the oxbow lake. The oxbow was a tool used to drive cattle to plow in the countryside in the past. It was shaped like a herringbone. It was placed on the neck of the cattle when plowing, in order to give the cattle a place to make strength. .
Owbow Lake is not unique to Northeast China
Other very flat river banks in the world are also easy to appear
(Picture: westend61/Picture Chong Creative)▼
On the plain, the river course of the river often changes, and the small ups and downs of the terrain will make the rivers with insufficient potential energy flow slowly and curvedly on the plain. This is how the famous landscape of Mohe’s nine bends and eighteen bends was formed.
It’s really turbulent flow
(near Mohe, picture: google map)▼
Under the impact of the river, the erosion on the concave side of the river bank will become more and more serious, so the degree of curvature of the river bend will also increase over time. Slowly, the most curved part of the river became an extreme herringbone shape, very similar to an ox yoke.
This is how it came
(Picture: shutter-wickerwood)▼
There are no tall rocky mountains on both sides of the river bank of the Northeast PlainThe river is blocked by the veins, so the increasingly curved river will eventually be cut and straightened when the curve of the river turns reaches a certain limit due to the forward momentum of the water. The original curved river channel is abandoned to form an oxbow lake.
Those oxbow lakes that lack water supply and cannot flow into the rivers remain on the plain. They are an important factor in the formation of wetlands.
Along the Nenjiang River, I don’t know how many oxbow lakes and oxbow lakes are semi-finished products
(Along the Nenjiang River, picture: google map)▼
Another factor that causes a large area of wetlands in the Northeast is cold. The forest area in the northeast of China is the coldest place in China. The temperature in winter can reach an extreme of -50℃. Even the third largest river in my country, Heilongjiang, will inevitably be frozen in winter.
Heilongjiang and its two sides
(Picture: google map)▼
Heilongjiang and the downstream part of the Amur River outside its borders have a total area of 4,440 kilometers, spanning 7 latitudes from north to south and about 750 kilometers.The highest degree area. This has led to the freezing of the lower reaches of the river earlier than the upper and middle reaches of the river. Every November around the beginning of winter, the mouth of the Amur River is blocked by ice. The water level of the middle and upper reaches and tributaries of the Songhua River rises. The river overflows in some areas, and the surface water accumulates in Niujiao Lake. Frozen on the plain together.
Because the downstream is colder than the upstream, it freezes earlier
The upstream river water will overflow to both banks
This is also a common condition for rivers flowing northward in cold regions▼
After the beginning of spring, the northeast region gradually melted from south to north, and the scene of overflowing rivers was staged again. At this time, the frozen surface water, snow and frozen soil that were frozen on the plain melted together, forming a large area of moist land. The locals call it “paozi”, or wetland.
Wetlands have diverse ecological and environmental functions. Northeast China is not only a key area for wetland and water biodiversity, but also the main summer habitat for Stork and Gruiformes. When the flowers bloom every spring, There are a large number of red-crowned cranes flying back from the south, screaming in the humid land of the northeast.
A crane was found
(Picture: shutter-Tada Images)▼
Happy Cow
In the water system network composed of Heilongjiang lakes, wetlands and river networks, there is a special water area called Zhalong Wetland. Its formation depends on the largest inland river in Heilongjiang in my country-Wuyuer River.
Beside the Nen River, you can find the Wuyuer River
The Wuyuer River originates from Xiaoxing’an Mountains, first to the west and then south to the Zhalong Wetland▼
Geographically, we call rivers that do not flow into the ocean as internal rivers. Inland rivers are common in northwestern China. Due to drought and low rainfall and high evaporation, many rivers are completely evaporated or infiltrated into the ground before they are poured into large rivers.
The most iconic such as Lop Nur
After many upstream water sources were cut off, this big lake disappeared
(Picture: NASA)▼
There is such a river in Heilongjiang, my country. It is located in a humid temperate monsoon climate zone, supplemented by mountain melt water, and surrounding rivers and lakes, but it is an inland river.
This river is the Wuyuer River in Heilongjiang Province. It originates from the melting water of snow and ice in the Xiaoxing’an Mountains and flows from the valley to the Songnen Plain. After going down the mountain, the flow slows down. The Wuyuer River was originally an outflowing river that injected into the Nenjiang River. Later, the Nenjiang River was diverted to the west, and due to the impact of the siltation of the estuary, the river channel turned to the south.
Wuyuer River twists and turns all the way to the south
and a series of oxbow lakes are outlined along the way
(Picture: google map)▼
Due to the flat terrain, the water lacks forward power, and the river downstream is low-lying, the water spreads over the plain depressions to form a vibrant wetland, which is called the Zhalong Wetland.
The aquatic plants are lush and lively
(Picture: User from sunny to cloudy / Graphworm creative)▼
The natural conditions of the Zhalong Wetland are extremely superior. On the fertile black soil in the northeast, the wetland and meadow soil are rich in organic matter, which is suitable for comprehensive development of agriculture, forestry, animal husbandry, sideline and fishery. The middle and lower reaches of the Wuyuer River, including the Zhalong Wetland, is one of the commercial grain bases in Heilongjiang Province. Grain production and plain animal husbandry are the main force of the regional economy and an important business card for the economic industry of this region to move towards the country.
There are many types of vegetation such as meadow grassland, wet meadow, swamp vegetation, aquatic vegetation, etc. The coverage rate of tall grasses such as reeds exceeds 90%. Grass is a major group of forage grass and a favorite source of feed for animals such as cattle and sheep.
“True fragrance”
(Picture: GIS / Graphworm Creative)▼
Wetland gramineous forages have high water content and high sugar content. After being chopped, they can be processed into silage through the fermentation of anaerobic lactic acid bacteria. Silage is soft, juicy, and nutritious. The most important thing is that it is conducive to preservation. In the long winter in the northeast, livestock can still eat fresh and palatable feed, which solves the problem of lack of forage in autumn and winter while maintaining the health of cattle and sheep.
Ensilage is a good choice in winter
(Picture: SGr/Picture Chong Creative)▼
Especially for dairy cows during lactation period, compared with dry forage silage, it can provide more sufficient nutrition and moisture, meet their demand for intake of trace elements and vitamins, and prevent dairy cows from suffering from diseases in the harsh winter environment in the north. The milk volume and the nutrient content of the milk have decreased, making the quality of the milk source more secure.
In addition to feed, the water in Zhalong Wetland is also good for health. The wetlands in the Songnen Plain are called “alkali foam” in the local area. Due to geological activities, the groundwater in western Heilongjiang and surrounding ores will dissolve and corrode, forming natural weakly alkaline soda water. Drinking by livestock is beneficial to regulate metabolism, remove acidic waste and prevent disease.
This article is from the official account: Earth knowledge Bureau (ID: diqiuzhishiju) , author: Narisu