What Are the Different Aquatic Jobs?

Aquatic life is a general term for living things in various water bodies. There are many types of aquatic organisms, including various microorganisms, algae and aquatic higher plants, various invertebrates and vertebrates. It also has a variety of lifestyles, including floating, planktonic, swimming, fixation and cave-dwelling. Some are suitable for living in fresh water, while others are suitable for living in sea water. Aquatic organisms provide humans with proteins and industrial raw materials, which have important economic value.

Water is the perfect environment for creating life. It is vital to the chemical reactions that organisms produce, so there is no doubt that life may start in shallow waters. Most life on Earth still lives in oceans, lakes and rivers. There, it has evolved into a variety of stunning forms ranging from microscopic plankton to giant fish ^[1]

Although there are many types of aquatic organisms, they are divided by function, but

Phytoplankton survey

Plankton take one qualitative sample at each sampling point every season, and use the No. 25 plankton net to take a shape at 50 ~ 100cm below the water surface. The quantitative sample of phytoplankton is collected from upper and lower water with 1L water collector. The layer was mixed with 1 L of water sample, and the sample was fixed with 1.5% iodine solution, brought back to the room, precipitated, concentrated, and identified under an optical microscope.

2. Zooplankton survey method

Qualitative samples of zooplankton were collected by shape at 50 ~ 100cm below the water surface using plankton net No. 13; quantitative samples of zooplankton were collected with 20L of mixed water samples from upper, middle and lower layers with 5L plexiglass water collector, and then used No. 13 The plankton net was filtered and concentrated, and the samples were fixed with 5% formaldehyde and taken back to the room for identification under an optical microscope.

3. Survey methods of benthic animals

According to the characteristics of the research environment, the samples come from different niche habitats, using a combination of quantitative and qualitative sampling and repeated quantitative sampling; the tools for quantitative collection are mainly Sauber nets and Peterson mud harvesters (1 / 16m ² ); Collection mainly includes D-type dip nets and hand nets. The obtained biological specimens were stored in 75% ethanol. The Peterson Mud Collector collects 2 samples at each sampling point. The collected sample is initially filtered with a sieving filter to remove large particles. It is fixed on the spot in a 10% formaldehyde solution, returned to the laboratory, rinsed with water in a sieve, and then placed in a white disk, using tweezers or a straw. Specimens are collected after picking and stored in 75% ethanol ^[2]

In China's vast land, rivers are crisscrossed, lakes are scattered, and the area of inland water bodies accounts for about 1/50 of the total area of the country, and aquatic biological resources are extremely rich.

However, due to unscrupulous hunting, environmental damage caused by human activities, water pollution caused by industrial wastewater, and flora changes caused by unplanned stocking, the destruction of China's aquatic animal resources has reached a very serious level, so much that Rare species are endangered.

Taking the world's rare freshwater whale, the white-fin dolphin as an example, it is a mammal and is one of the only five freshwater whales remaining in the world today. It is a specialty of China.

The white-fin dolphin mainly feeds on fish and shrimp. Because it is an ancient relic, it has a weak ability to adapt to environmental changes. Generally, the decline of water level or the decrease of food bait may affect its population's tendency to decline. Therefore, the protection of the white-fin dolphin is increasing. Urgent. In recent years, individual white-fin dolphins have been caught swimming in shallow water and have been used as scientific research materials. It is extremely beneficial to further study their habits for artificial feeding.

At present, the Xinluo Nature Reserve in Hubei Province is a nature reserve that protects white-fin dolphin, and its important scientific research value has been gradually valued. Now a male juvenile white-fin dolphin domesticated by Wuhan Institute of Hydrobiology, Chinese Academy of Sciences has been living for several years and lives normally. It is hoped that breeding will be carried out at home.

It is worth noting that there are many unique species of freshwater organisms in China. There are only 400 species of fish, and most of them have economic value. Among them are white magpie, sichuan tilapia, rouge, tufted bream, Songjiang bass, Dali rift. Rare species such as belly fish, flower eel, and sweetfish have been severely damaged, and some are even endangered. At present, only the two nature reserves of Huma River and Xembela River in Heilongjiang Province are clearly designated as protection areas for salmon and catfish. However, these two protection areas alone cannot meet China's protection of fish resources, so it is recommended Establish nature reserves in the following two areas:

1. Tongjiang Lake Reserve in the middle and lower reaches of the Yangtze River

Cooperating with the protection of Yangtze River fish spawning grounds, the reserve can protect the natural populations of farmed species such as green, grass, magpies, and cockles, in order to maintain the natural gene bank of the breeding objects, and at the same time protect the magpies, magpies, and whales , Catfish, catfish, copper fish, and some small fishes and catfishes of the subfamily, and subfamily. In this way, the basic state of freshwater fish fauna in the middle and lower reaches of the Yangtze River can be maintained, and research on aquatic ecosystems can be carried out. Fishes in the middle and lower reaches of the Yangtze River have special and important economic significance in the world's freshwater fishes. This protected area should be established as soon as possible.

2. Yunnan Plateau Lakes and Fishes Nature Reserve

The taxonomy of fish fauna in Yunnan Plateau is simple, and the species differentiation is complex. There is only one genus of carp, which is a species throughout the country, but 12 species and subspecies are differentiated in lakes in Yunnan, and they are all endemic species. These are good materials for studying genetic laws. In addition, there are endemic species of fissure fish and abalone in the lake. At present, due to improper introduction and stocking, the region's natural ecosystems have disintegrated, and endemic endemic species are gradually disappearing, so protection measures must be taken quickly.

The establishment of these two protected areas cannot solve the problem of protection of freshwater biological resources, but it is not possible to establish many protected areas immediately. Therefore, in the already established wild animal nature reserves, the aquatic organisms in the area should be protected at the same time, or some precious aquatic organisms should be introduced and protected. For example, the Changbai Mountain Nature Reserve in Northeast China can take into account the protection of salmon and trout and other cold-water fishes. The Western Sichuan Giant Panda and Golden Monkey Nature Reserve can pay attention to the protection of Sichuan pheasant and some fissure fish at the same time ^.

Since the Songhua River Rest and Restoration Policy was fully implemented in 2007, the aquatic ecology of the main stream of the Songhua River has continued to recover. The zoobenthos community is relatively stable and the species diversity is rich. Most sections have detected clean aquatic insects. The water environment of the Harbin River section has been improved significantly. The aquatic ecology of the Jiamusi River section is recovering year by year. The benthic fauna increased from 16 genera in 2009 to 27 genera in 2012, and the number of algae increased from 24 taxonomic units in 2009 to 37 in 2012. The clean (stone flies) larvae were continuously distributed after 2007, and the larvae of the pupae family also appeared in this river section in the past two years, and the number of clean species has been increasing ^[4] .