As the launch date of Shenzhou 18 approaches, the mission of Shenzhou 18 has also been announced, and among them, the most curious is the "space fish farming" project.
According to the project introduction of Shenzhou 18, the first domestic research on the aquatic ecology project in orbit in outer space will be carried out, and the research objects are zebrafish and goldfish algae.
This research will achieve the first breakthrough in the continent's space cultivation of vertebrates, and the first international in-orbit study of plant stem stem cell function, which will reveal the adaptation mechanism of plants to zero gravity in space.
The significance of these experiments is to find and cultivate plants that adapt to the space environment in the future, and unlike space seeds, the purpose of this experiment is to be able to reproduce and survive in the future in the true sense of zero gravity in space.
Japan has done the same experiment
In fact, the experiment was preceded by the Japan Space Agency's previous experiments, when Japan sent an aquarium to the space station in July 2012.
At that time, the aquarium was called the "Aquatic Habitat (AQH)" and was loaded on a cargo spacecraft sent by Japan and transported to the International Space Station.
At that time, the experimental aquarium consisted of four main parts, two fish habitats, a water circulation system, a control unit and a camera.
The control unit mainly includes automatic feeding of fish, oxygen injection, temperature control and filtration system. During the experiment, the growth of fish was monitored throughout the experiment to record the living conditions of fish in space.
However, unlike the zebrafish that China chose this time, Japan chose medaka last time. At that time, there were several main considerations for the selection of medaka in Japan.
First of all, medaka fish is transparent, which is conducive to observing the changes in organs in the body through the skin of the fish, and at the same time, fluorescent proteins can be used as markers to record the changes in cells and genes of medaka fish under space radiation.
In addition to this, medaka fish, like zebrafish, are vertebrates and can be studied in how their bones and muscles are affected in space microgravity.
In addition to the characteristics of being easy to observe, medaka fish also have another characteristic, that is, fast reproduction. Due to this feature, these fish can reproduce for many generations during missions in space.
Japanese astronauts can analyze the growth trajectory of some fish that have been born in space since childhood, and what changes will occur in their bodies from the whole process from hatching to growth.
Another important point is how the body organs, cells and genes of medaka fish that have undergone many generations in space will be transformed under microgravity and high radiation.
These experimental data will be used as a reference sample to infer the physical changes of human beings in space for a long time, and also provide a theoretical basis for future interstellar migration.
Why did China choose Indian zebrafish instead of native Chinese medaka, and how did it differ from the Japanese experiment?
Although China's experiment is all about raising fish in space, the nature is different, and the first fish selected are somewhat different, Japan chose medaka fish that is easy to observe, while China chose zebrafish.
Zebrafish is an ornamental fish that has beautiful stripes on its body, just like the markings on the zebra's body, so it is named zebrafish.
Zebrafish are native to the waters around India, whereas medakafish are native to the waters around China and Japan. Morphologically, the two also have many similarities, both are relatively small, short-lived, and have a relatively strong reproductive ability.
Both of these fish have a mixed diet, both are omnivorous fish, and both prefer to live in a freshwater environment with slow currents and abundant aquatic plants, and there are many similarities between the two in addition to their origin and skin color.
So why choose zebrafish instead of medaka fish?
In fact, both medaka fish and zebrafish are ornamental fish, and they are widely used in scientific research, but due to the characteristics of the two fishes, their research directions are also different.
At present, the main research directions of medaka fish are developmental biology, molecular biology and toxicology, and it can be seen that it is mainly the study of cell proliferation, gene mutation and pollutant toxicity of vertebrate organisms. When it comes to pollutants, the first thing that comes to mind is what comes to mind, so it is clear that Japan's choice of medaka fish has its own purpose.
Zebrafish mainly exposes the development of embryos and tissues and organs, studies the relationship between zebrafish and the environment, and solves major problems in environmental science and agricultural science, and there are currently more than 1,500 zebrafish laboratories around the world.
From the above research directions, medaka fish studies individual changes, while zebrafish studies overall environmental changes.
Therefore, this time, China brought not only zebrafish to the space station, but also goldfish algae, a plant in the water. It is also clear that we are not limited to one type of fish, but the entire ecosystem.
In the process of farming, there will be not only zebrafish and goldfish algae, but also other microorganisms, so we can observe what kind of changes will occur in this ecosystem in the space environment of microgravity and high radiation.
These scientific studies are not just for each individual in the ecosystem, but also for the entire ecosystem as a whole.
Therefore, just from the matter of "raising fish in space", we can see what a big country is, what is the mentality of a big country, and what is the mentality of a small country?