Hirondellea gigas is an ultra-deep sea creature that lives in the deepest part of the Mariana Trench Challenger Deep in the world. It was also confirmed that it inhabits the Izu-Ogasawara Trench near Japan and the ultra-deep waters of the Japan Trench. Hirondellea gigas is a species of gammaridea, and its scientific name is Hirondellea gigas. In fact, it is one of the most studied deep-sea creatures.

What do you eat and live in the desert of the sea, the ultra-deep sea?

 In general, gammaridea live by eating the carcasses, excrement, and microorganisms of other creatures. However, because of the extremely high water pressure in the ultra-deep sea, there are not many organisms and species. For this reason, the ultra-deep sea is called the "sea desert." Of course, food problems are also serious for Hirondellea gigas. In the deepest part of the world with ultra-high water pressure, we have no choice but to rely on things that fall from land or shallow sea.

​

 Falling objects include corpses and excrement of living things, and plant fragments from land. However, the carcasses and excrement of living things are also a treat for fish, shrimp, crabs, and microorganisms that live in shallow waters and middle layers. It hardly reaches the bottom of the deep sea where Hirondellea gigas live. On the other hand, plant pieces such as driftwood and fallen leaves fall without being eaten on the way. Therefore, Hirondellea gigas feeds on this piece of plant. Other fish, shrimp and crabs do not eat plant pieces. This is because plant pieces cannot be broken down into nutrients. Hirondellea gigas, on the other hand, has an enzyme that can break down plants into sugar. Hirondellea gigas can live in the deep sea without food by eating driftwood and fallen leaves that fall from the land.

Why there are no shrimp and crabs in the ultra-deep sea

Shells of shellfish, shrimp and crabs are very strong. Its tough shell is made of calcium carbonate crystals. In the case of shrimp and crabs, their feet and hands are also covered with shells, which are used to grab or pinch something. For shrimp and crabs, hard shells are a daily necessities. However, shrimp and crabs with hard shells are rarely found in the ultra-deep seas that exceed 5000 m in depth. This is because high water pressure melts calcium carbonate crystals in the ultra-deep sea. Therefore, shrimp and crab cannot live in the deep sea.

The shell of Hirondellea gigas doesn't melt even in the ultra-deep sea.

Hirondellea gigas inhabits the ultra-deep waters where calcium carbonate dissolves. However, the shell of Hirondellea gigas is made of calcium carbonate crystals. Why doesn't calcium carbonate dissolve? This is because the surface of Hirondellea gigas is covered with aluminum gel. Aluminum gel is made of aluminum hydroxide. Previously, aluminum gel was added to headache medicines as a protective agent for gastric mucosa. Aluminum gel protects Hirondellea gigas and prevents the dissolution of calcium carbonate .

 

There are still many secrets of Hirondellea gigas. Where do you bring aluminum, which is rarely contained in seawater? Not explained here. Hirondellea gigas, which live in the deepest parts of the world, are creatures that fascinate the evolutionary results of living organisms in various places.