The four zebrafish that China sent to its space station are thriving after spending nearly a month in orbit.
Launched on April 25 along with three astronauts aboard the Shenzhou-18 spacecraft, the zebrafish and four grams of goldfish algae are currently in good condition in their aquatic habitat on China’s Tiangong space station, the Xinhua News Agency reports this.
The so-called “aquastronauts” are part of a research project led by the Chinese Academy of Sciences (CAS) to study the impact of microgravity and a limited ecosystem on the growth, development and behavior of vertebrates. The study – the country’s first aquatic ecological research project in orbit – was based on establishing a self-sustaining aquatic ecosystem in orbit.
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Chinas Tiangong Space Station orbits the Earth at an altitude between 340 and 450 kilometers, which is approximately the same orbital altitude as the Earth. International Space Station (ISS). Astronauts (or taikonauts, as the Chinese space fliers are called) studying zebrafish have successfully collected water samples twice and replaced the fish food box once. This initiative marks the first experiment of its kind in growing vertebrates in space, according to Xinhua.
The zebrafish, a small fish species belonging to the minnow family, are one of the most widely used model organisms for genetic and developmental studies. The research currently underway at Tiangong will investigate the effects of microgravity and radiation on biological systems and help reduce bone loss in astronauts.
Seen microgravity environment on Tiangong, the astronauts also observed that the zebrafish exhibit unusual directional behavior such as reverse swimming and turning movements, Zheng Weibo, a researcher at the Shanghai Institute of Technical Physics of the CAS, told a public science day in Beijing on May 19.
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“Zebrafish, as a model animal with genetic similarity to humans, can be used for research into many human diseases,” said Wang Gaohong, a researcher at the Institute of Hydrobiology of the CAS, in the Xinhua report. According to the National Institutes of Health, about 70% of human genes have an analogue in the zebrafish genome.
In addition to water samples, the astronauts will collect samples of fish eggs for their research. Zebrafish serve as a unique biological model because their embryos are transparent and develop outside the uterus, meaning the fish’s development can be studied from fertilization onward.
Furthermore, the self-sustaining aquatic ecosystem, where algae and fish sustain each other, also has implications for understanding the challenges of maintaining life support systems for long-duration space missions and future space habitats.
