Tardigrades are known to be the toughest animals in nature. They are ways to harness a unique form of suspended animation and to endure fatal conditions of high temperatures and pressures and even a cosmic vacuum. Scientists have discovered a new species of tardigrades that expands on this survival toolkit by using a kind of fluorescent “screen” to ward off lethal ultraviolet radiation. Reported by New Atlas.
Tardigrades are believed to be one of the few species to have survived all five global mass extinctions. These creatures do not require comfortable conditions for survival, as they can do without food, water and oxygen.
Researchers at the Indian Science Institute are studying the survival mechanisms of tardigrades by collecting local specimens and exposing them to extreme conditions. In one experiment, scientists exposed tardigrades to a UV germicidal lamp in doses sufficient to kill bacteria and roundworms in minutes.
Tardigrades of the species Hypsibius instanceplaris lasted a little longer, withstanding about 15 minutes of exposure to ultraviolet radiation, but another unknown species turned out to be completely immune to UV rays. All specimens of the new species survived. They were even treated with four times the dose, with about 60% of the test subjects continuing to live for another 30 days.
An unusual species of tardigrades was found on a simple moss-covered concrete wall – they are part of the genus Paramacrobiotus. Further studies using an inverted fluorescence microscope showed that microscopic water bears under the influence of UV light changed color from reddish brown to blue.
Scientists have concluded that a set of pigments under the skin are responsible for this, which act as a shield, absorbing deadly light and converting it into soft blue light. Researchers were able to extract these pigments and transfer them to earthworms to enhance their survival when exposed to ultraviolet light. The team believes the new tardigrade species may have developed a protective shield due to the strong sunlight in the tropics of southern India.