脱炭素社会とカイコウオオソコエビ(その2)(Decarbonized society and Hirondellea gigas, part II)

2021/01/31 ブログ















#カイコウオオソコエビ #脱炭素社会 #金属精製

Last time, I talked about the digestive enzymes of Hirondellea gigas. This time, I will talk about the secret of the shell of Hirondellea gigas. Hirondellea gigas is a member of the crustacean family. Like shrimp and crab, it has a "shell" on the outside. This shell is hard and can protect you from foreign enemies and protrusions in the environment. Then, as they grow and grow larger, they molt and make new shells. This hard shell is made of calcium carbonate crystals. The ingredients are the same as seashells. In fact, it is strange that crustaceans with hard shells live in the deep sea.


In the deep sea, calcium carbonate dissolves.


When the water depth becomes deep and the water pressure becomes high, there are various effects on living things and things. One of them is that calcium carbonate dissolves. Even hard crystalline calcium carbonate will dissolve in the deep sea as well. Calcium carbonate begins to dissolve from a depth of 5000-6000m. The deeper the water, the faster it will dissolve. Therefore, if the water depth exceeds 5000m, the number of shellfish and crustaceans will decrease. This depth is called carbonate compensation depth. As a result, attempts to prevent global warming by accumulating carbon dioxide, a greenhouse gas, in the deep sea were not carried out due to the dissolution of carbonates. Therefore, the Hirondellea gigas, which inhabits the ultra-deep sea at a depth of over 8000 m, is a very mysterious creature. In the past, many foraminifera were found in the Mariana Trench Challenger Deep. Foraminifera have a calcium carbonate shell and are organisms with various morphologies. However, the foraminifera that live in the Mariana Trench Challenger Deep were all foraminifera with organic shells rather than calcium carbonate.


Hirondellea gigas had a crystalline calcium carbonate shell.


Analysis of the shells of Hirondellea gigas revealed the presence of crystalline calcium carbonate. Originally, the calcium carbonate that melted out was maintained. In addition, aluminum was also present in the shell of Hirondellea gigas. Aluminum is one of the elements with the third highest Clarke number, but it is rarely contained in seawater. Almost all of the aluminum is contained in the rock. Surprisingly, the Hirondellea gigas was extracting aluminum from the rock. Aluminum becomes an "aluminum gel" in a weakly alkaline environment such as seawater. In fact, aluminum gel was used as a headache remedy and cold remedy for a while as a component that protects the mucous membrane of the stomach. The aluminum gel covered the surface of Hirondellea gigas and protected the crystalline calcium carbonate inside.


Use of the Hirondellea gigas system for a carbon-free society


Electric vehicles and hydrogen vehicles are often cited as symbols of a carbon-free society. However, the industry that really uses energy is actually the metal industry. A lot of energy is used and carbon dioxide is released in the process of extracting iron and aluminum from iron ore and bauxite and refining them. However, Hirondellea gigas uses very little energy in the process of extracting aluminum from minerals. Since aluminum is extracted in the deep sea with a water temperature of 2 ° C, it does not use extremely high temperatures of hundreds of degrees Celsius or dangerous chemicals such as strong acids and strong alkalis. The metal extraction system of Hirondellea gigas will enable the purification of metals without emitting carbon dioxide.

That's all, but please refer to the paper for detailed data. Also, please contact us by email.

#Hirndellea_gigas #DecarbonizedSociety #Metal_refining