They actually live on the seabed where there is no sunlight!

The mid-ocean ridge is 2000~3000m below the sea surface. It is deep enough that sunlight cannot reach here.

Distribution map of mid-ocean ridges | wwiki.com

We know that sunlight, air and water are the basic elements that constitute life. So, in such a "harsh" environment, will this be a "desert" of life?

Most of the top of the mid-ocean ridge is a central rift valley formed by seafloor spreading, which contains hydrothermal vents.

Schematic diagram of mid-ocean ridge, central rift valley and hydrothermal vents | cn.bing.com

It's like a Russian nesting doll: the mid-ocean ridge contains a "small" central rift valley, and the "small" central rift valley contains a "small" hydrothermal vent.

In recent decades, scientists have discovered a large number of biological communities near hydrothermal vents. These communities are composed of many organisms unknown to humans, and the size of the organisms at this depth appears to be abnormally large .

Tube worms | pic.sogou.com

Clams | bbs.voc.com.cn

Mussels | www.sohu.com

Including tubular worms up to 1.8m long, clams with shells up to 25cm wide, giant mussels, etc. Look at the clams and mussels above. Do they look like the " meals on the plate " we are familiar with?

In areas where nutrients are scarce and life is scarce, hydrothermal vents are veritable " oases " in the deep sea. Why are these areas so rich in life?

Located 2,500m deep in the Galapagos Rift Valley near the equator of the eastern Pacific Ocean (near the Galapagos Islands named after "The Origin of Species"), it is the first active hydrothermal vent discovered by humans.

Galapagos Islands | pai-hang-bang.cn

The water temperature near the spring here is 8℃~12℃, while the normal water temperature at this depth is about 2℃.

In the " Ocean Today " exhibition hall of the National Museum of Marine Life, there is a simulated scene of hydrothermal vents and nearby ecosystems .

Simulation of hydrothermal vents and nearby ecosystems

Doesn’t this tall, protruding thing look like a factory chimney? Plus, it spews out hot water (350°C) rich in metal sulfides, which turns the water black, so we gave it the common name of “ black chimney ”.

"Black Chimney" | www.sohu.com

Its ejecta are extremely toxic seawater, including black metal sulfides of iron, nickel and copper, but such seawater is rich in microorganisms. Therefore, in the absence of photosynthesis, warm water and an ecosystem based on chemical synthesis have created this underwater oasis. At this point, I guess everyone will want to ask a question: Can the shellfish found in the hydrothermal vent be eaten?

Unfortunately for humans, they are not edible because the microorganisms that form the basis of the food web use hydrogen sulfide as their energy source (hydrogen sulfide, you may be familiar with it, it has a very special smell, it smells like rotten eggs).

However, hydrogen sulfide is a deadly poison to most organisms (even in low concentrations), and although organisms in vent communities have mechanisms to excrete sulfide, vent organisms may still be toxic to humans.

Even if they are edible, organisms collected from hydrothermal vents are extremely valuable because they live at such great depths and are more suitable for scientific research.

Scientific research shows that life originated in the ocean, and that the environment at the beginning of the Earth's formation was similar to hydrothermal vents, which are ideal habitats for the origin of life. In fact, since hydrothermal activity is often accompanied by the presence of volcanoes and seawater, hydrothermal vents may represent one of the oldest environments that can sustain life.