One calls an ecosystem that has water as its natural habitat. It determines the uniqueness of an ecosystem, its species diversity and its sustainability.

The main factors that affect the aquatic ecosystem:

1.Water temperature

2.Its chemical composition

3.The amount of salt in the water

4.Water transparency

5.The concentration of oxygen in the water

6.Availability of nutrients.

The components of an aquatic ecosystem are divided into two types: abiotic (water, light, pressure, temperature, soil composition of the day, water composition) and biotic. Bioethics, in turn, is divided into the following subspecies:

Producers are organisms that produce organic substances using the sun, water, and energy. In aquatic ecosystems, algae are the producers, and in shallow water bodies, coastal plants are the producers.

Reducents are organisms that consume organic matter. These are various types of marine animals, birds, fish, and amphibians.

In ecology, water ecosystems are usually divided into freshwater and marine. This division is based on the salinity index of water. If a liter of water contains more than 35% of salts, these are marine ecosystems.

The sea includes oceans, seas, and salt lakes. Freshwater-rivers, lakes, swamps, ponds.

Another classification of aquatic ecosystems is based on such a feature as the conditions of creation. There are natural and artificial ones. Natural resources are created with the participation of the forces of nature: seas, lakes, rivers, swamps. Artificial water ecosystems are created by humans: artificial ponds, reservoirs, dams, channels, and water farms.

Freshwater ecosystems are rivers, lakes, swamps, and ponds. All of them occupy only 0.8% of the surface of our planet. Although more than 40% of the fish known to science live in freshwater reservoirs, freshwater ecosystems are still significantly inferior in species diversity to marine ones.

The main criterion for distinguishing freshwater reservoirs is the speed of water flow. In this regard, there are standing and flowing ones. Standing areas include swamps, lakes, and ponds. Rivers and streams belong to the flowing ones.

Standing water ecosystems are characterized by a pronounced distribution of biotic organisms depending on the water layer:

In the upper layer (the littoral zone) is the main component of the plankton and coastal thickets of plants. This is the Kingdom of insects, larvae, turtles, amphibians, waterfowl, mammals live here. The upper layer of reservoirs is a hunting ground for herons, cranes, flamingos, crocodiles, and snakes.

The middle layer of the reservoir is called profundal. It receives much less sunlight, and the food is substances deposited from the upper layer of water. It is home to predatory fish.

The lower layer of water is called bental. A huge role is played by the composition of the soil, silt. This is a habitat for bottom-dwelling fish, larvae, mollusks, and crustaceans.

The largest marine ecosystem is The world's ocean. It is divided into smaller ones: oceans, seas, and salt lakes. All of them occupy more than 70% of the surface of our planet and are the most important component of The earth's hydrosphere.

In marine ecosystems, the main component that produces oxygen and nutrients is phytoplankton. It is formed in the upper layer of water and under the influence of solar energy produces nutrients, which then settle in the deeper layers of the reservoir and serve as food for other organisms.

Large marine ecosystems are oceans. In the open ocean, species diversity is low compared to coastal zones. The main mass of living organisms is concentrated at depths of up to 100 meters: these are various types of fish, shellfish, corals, and mammals. In coastal zones of marine ecosystems, species diversity is supplemented by numerous species of marine animals, amphibians, and birds.

In coastal zones of marine ecosystems, there are smaller ones (by territory): mangrove swamps, shelves, estuaries, lagoons, salt marshes, and coral reefs.

Places on the coast where sea water mixes with fresh water (river mouths) are called estuaries. Species diversity is maximized here.

All marine ecosystems are highly resilient, able to resist human intervention, and recover quickly from human influence.

All artificial water ecosystems are created by humans to meet their own needs. These are various ponds, channels, backwaters, reservoirs. Smaller ones include aquariums and aquariums.

The following features are characteristic of artificial aquatic ecosystems: 

Small number of plant and animal species 

Strong dependence on human activity

The fragility of the ecosystem, as its viability depends on human influence.

The Japanese archipelago stretches widely from North to South and from West to East. So here you can see different pictures: the sea with the drifting ice of the sea of Okhotsk, and the sea in the Okinawa region, where one of the most outstanding coral reefs in the world is located.

Thanks to the Kuroshio current, which carries warm water from the South, and the Kuril current, which carries cold water from the North, rich in nutrients, the area of Japan has very rich ecosystems in terms of species diversity. 33 thousand species of living creatures live in the sea waters of Japan, which is 14.6% of the total number of living organisms in the world. In terms of marine biodiversity, it has some of the richest water areas.

The Japan sea is a closed water area, which is surrounded by the Japanese archipelago, Korean Peninsula, Eurasia, and which is outside the Pacific ocean only through four Straits (Korea Strait, Tsugaru Strait (Tsugaru), La Perouse Strait, Tartar Strait) with a depth less than 100 m. The average depth of the sea of Japan is 1752 m, the deepest depression reaches 3742 m. In the sea of Japan, warm and cold currents are also intertwined. The warm Tsushima current – a branch of the Kuroshio current-carries its waters along the shores of the Japanese archipelago from South to North. Liman current-along the coast of the continent from North to South. At a depth of more than 300 m, the deep waters inherent in the sea of Japan flow with a temperature below 1 ° C and a high concentration of salt.

The formation of the sea of Japan began 24-17 million years ago, and the current form took 8 thousand years ago. During the ice age, when temperatures dropped significantly everywhere on earth, 1 the sea surface was lower than it is now by 100 m and there was a time when communication with the Pacific ocean was very weak. During this period, the exchange of water between the deep and surface layers (vertical circulation) was carried out very poorly. As a result, the supply of oxygen to the deep-sea layers decreased and a low-oxygen environment was formed closer to the sea floor. At this time, many bottom animals became extinct, and most of the animals that now live in the sea of Japan are animals that appeared there from the Pacific ocean when the sea joined the ocean after the ice age.

1 New century of Oceanology of the sea of Japan. Ed. Council for the development of the Japanese marine science. Publishing house of Kadokawa

Endemic species of living organisms in the sea of Japan that have escaped extinction are valuable species that need to be preserved.

But, unfortunately, there is little information about the animal world of the sea of Japan, because not enough research is being done. Therefore, it is necessary to jointly collect data on what living organisms exist in the sea of Japan and where they live.