Marine food chain refers to the demand relationship between predators and prey in marine biological communities, starting from autotrophic bacteria or organic matter formed by photosynthesis, passing through plankton, herbivores and carnivores at all levels. The structure of the food chain is similar to a pyramid, with a large base, and each level is smaller than the previous level. The whole network consists of various complex food chains. For example, the most common: algae-small fish, shrimp-shark, mackerel, tuna and so on. Some will emit ultrasonic waves, such as whales. Some emit infrasound waves, which are usually used to call for companions or courtship. Predators usually catch up with their prey by surprise or speed, while predators who feed on zooplankton are slow. Underwater animals have their own characteristics.

Sea cucumber crawls by stretching its muscles and can only advance four meters per hour.

Barracuda can swim dozens of kilometers per hour, and when attacking other animals, it is faster than ordinary trains.

Squid and octopus can suddenly spray water forward and use the reverse thrust of water to quickly retreat.

Some shellfish can't move by themselves, but they can travel long distances under the boat for free.

There are also some deep-water fish, which have their own luminous organs and swim like twinkling stars.

There are also some deep-water fish, which have their own luminous organs and swim like twinkling stars.

Deep-water fish: sunlight can't reach the bottom of the sea. The deeper the water, the dimmer the light. The seabed 100 meter is brighter, but it is not so bright at 200 meters. 300 meters and 400 meters are all black, and all below 500 meters are black. But in this dark deep sea, there are many bright spots like twinkling stars, which is actually because many fish in deep water have luminous organs. On the one hand, the light it emits can be used as bait for predation, and on the other hand, it can be used as a signal for guarding the enemy and guarding jiè.

These deep-water fish mainly include: candlelight fish that can emit strong light at night; Bald fish with a flat back covered by a pair of luminous bodies; An arowana with countless luminous cells attached to its body; There is a "lighting lamp" under the eyes, which can emit strong white light, such as flashlight fish. Do you know what the underwater world is like?

When the sea is rough, the bottom of the sea is still calm. No matter how big the wind and waves are, they can only affect tens of meters below the sea surface. So, there's no sound at the bottom of the sea? Not exactly. Animals under the sea often whisper to each other, but we just can't hear them. If you use a special underwater listening device, you can hear all kinds of sounds: some buzz like bees, some chirp like birds, some bark like dogs, some snore like people ... They make one sound when eating, another sound when marching, and even give an alarm when they are in danger.

Benthic animals have their own activity characteristics. Sea cucumber crawls by stretching its muscles and can only advance four meters per hour. Barracuda can swim dozens of kilometers per hour, and when attacking other animals, it is faster than ordinary trains. Squid and octopus can suddenly spray water forward and use the reverse thrust of water to quickly retreat. Some shellfish can't move by themselves, but they can travel long distances under the boat for free. There are also some deep-water fish, which have their own luminous organs and swim like twinkling stars.

There are also great differences in marine benthos. Their colors are varied, such as brown, purple and red ... and their shapes are different. Take seaweed as an example. The smallest can only be seen clearly with a microscope, and the largest is 200-300 meters long, which is the longest creature on earth.

There are peaks and valleys on the seabed. It is rich in coal, iron, oil and natural gas, as well as rare metals with few reserves on land.

The seabed is really a world with strange scenery and rich products.