Last night (25th), the Shenzhou 18 manned spacecraft was successfully launched, and there were several special members of the 3 astronauts - zebrafish.
This time, the astronaut crew will carry out the first in-orbit aquatic ecology research project in China. In layman's terms, astronauts are going to raise fish in space. In space, what to do with the excrement of small fish? Without oxygen in space, how can small fish breathe?
How does the "space fish tank" maintain ecological balance?
Zebrafish is a very beautiful ornamental fish, about 3-4 cm long, slender body, from head to tail with multiple dark blue lines, like zebra, so it is called zebrafish.
The space fish tank in the sky is equipped with 4 zebrafish and goldfish algae. How does this "space fishbowl" maintain ecological balance?
Cang Huaixing, a researcher at the Chinese Academy of Sciences' Center for Space Application Engineering and Technology and a consultant for space science experiments, said that the "space fish tank" is an ecosystem that is "both beautiful and complex". Goldfish algae produce oxygen through photosynthesis to supply fish respiration, and fish excrement provides nutrients to the algae, and they are both producers and consumers of each other, forming a scientific experiment that looks simple, but is actually complex inside.
In the future, more in-depth research can continue to be carried out on a rolling basis, and the system will become more and more complex.
How does lighting work?
There is also a very important player in this ecosystem: sunshine. But in space, there is no regular day and night and light on Earth, how to solve this?
Experts told reporters that during the ascent of the manned spacecraft, the ascending aquatic support device will provide LED light source for goldfish algae to maintain normal photosynthesis and ensure that the oxygen content in the ecosystem meets the survival needs of zebrafish.
After entering orbit, the astronauts will transfer the experimental components to the small controlled life ecology experiment module of the life ecology experiment cabinet of the Wentian module to carry out on-orbit experiments.
How do you feed small fish in space?
The problem of sunlight is solved, and there is also the problem of water. In weightlessness, the water will be spherical and can even be held in the hand. Does this water allow small fish to swim in it? Will it not move because of weightlessness? And how can it be fed?
Wang Gaohong, a researcher at the Institute of Hydrobiology of the Chinese Academy of Sciences, said, "We designed a special fish food, like toothpaste, which is pushed with a syringe every day to let the fish eat as much as possible. The excrement produced by the fish after eating can be transported to the goldfish algae through pipes to encourage it to grow. ”
How long do small fish survive on the space station?
In keeping fish in space, the "fish tank" must be designed with great care, not only to seal well, but also to fill the water as much as possible. In addition to the "house" where he lives, the meal eaten by Xiaoyu is also a special "space meal". How long will these little fish survive on the space station?
Wang Gaohong said that the initial plan is to run stably for a month so that these zebrafish and goldfish algae can survive, and then obtain some experimental samples, such as fish eggs and water samples. Because of the constraints, it is not easy to cultivate in such a small space. As for whether it can be extended in the future, it depends on the actual situation in space.
In order to prevent the dead small fish and algae from rotting and deteriorating in the space station, the astronauts inactivated them after the experimental project. If the experiment goes well, the next generation of these small fish may be born on the ground.
Zhang Tao, a researcher at the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences, is looking forward to the small fish spawning in space, "Once we find that the fish are ovulating, we will activate a special ovulation device to collect the eggs." This is a tentative and exploratory work, and it is also the first time to do it in China, and it is the most distinctive part of this experiment. ”
Why are zebrafish in space?
Experts explain that zebrafish are vertebrates with vigorous vitality and strong reproductive ability, and they are also model experimental animals. Zebrafish have more than 70% similarity to the human genome, and this is the first vertebrate animal to be welcomed by China's space station other than astronauts.
For the first time, a confined space tank of zebrafish and goldfish algae will allow a continent to cultivate and reproduce vertebrates in space.
Source: CCTV News
Editor: Chen Meijuan (intern)