Preliminary results on the action of cosmic heavy ions on the development of eggs of Artemia salina.

The Biostack experiment (Principal Investigators: H. Bucker) aboard Apollo 16 contained one unit with eggs of the brine shrimp Artemia salina. The eggs were fixed in polyvinyl alcohol foils. Nuclear emulsions and plastics were used as track detectors. The development of 260 eggs hit by cosmic heavy ions was investigated. It differed significantly from the development of the flight controls--eggs flown in the Biostack but not hit by heavy ions--and of the ground controls. From these results it was concluded that a hit of a single heavy ion may injure the encysted blastula. This damage was found to influence the gastrula formation and even the hatching process of the nauplius. Abnormalities of the orthonauplius were observed during the development of the hit eggs. These are shortened extremities, or abnormal thorax or abdomen. In addition, in the Biostack II aboard Apollo 17 eggs of Tribolium confusum and Carausius morosus were included. The influence of single heavy ions on the development process of these highly organized insects was investigated.