A species of tardigrade shields itself from UV light using a glowing blue pigment, researchers have discovered.
Eswarappa found that like many other tardigrades, these Paramacrobiotus are resistant to ultraviolet radiation. After sitting under a germicidal UV lamp for 15 minutes — ample time to kill most microbes and give humans a skin lesion — all Paramacrobiotus specimens survived, seemingly unfazed by the ordeal. The secret of how these water bears persisted eluded Eswarappa and his team until one day when the researchers happened to view a tube of the ground-up tardigrades in a UV transilluminator, used to visualize fluorescence in the lab. To the team's surprise, the tube glowed blue.
Photo excerpted from H.R. Suma, S. Prakash and S.M. Eswarappa, Naturally occurring fluorescence protects the eutardigrade Paramacrobiotus sp. from ultraviolet radiation.