Science: Life in Time & Space

Two questions about life are asked over and over again. How long can organisms cling to the spark of life? Does life exist elsewhere than on earth? Last week scientists attempted to answer both questions—and thereby raised a scholarly scientific controversy.

In West Germany's highly respected Zentralblatt für Bacteriologie, Bacteriologist Heinz J. Dombrowski reported that he had revived dehydrated bacteria preserved in rock salt since the Permian Period 180 million years ago. In Britain's Nature, Dr. George Claus of New York University Medical Center and Chemistry Professor Bartholomew Nagy of Fordham University reported finding dead organisms that may have ridden in from outer space aboard meteorites.

Elaborate Precautions. Dr. Dombrowski got interested in ancient life when he noted that the warm, allegedly curative brine that comes to the surface near his laboratory at Bad Nauheim was full of living bacteria. They could not originate in the soil, he decided, because they are present in the water when it is still 600 ft. below the surface. Besides, they were a type whose modern representatives live in the sea. And along with the bacteria, the brine carried fossil pollen from trees that grew in the Permian.

Geologists know that the Bad Nauheim brine gets its salt from the thick Kali and Zechstein deposits 40 miles away, so Dombrowski next looked for bacteria in the salt itself. Guarding carefully against contamination by modern bacteria, he dissolved samples of Zechstein salt in sterilized nutrient broth. After a few days, he examined the broth, found it to be teeming with lively bacteria.

Sure that his colleagues would still suspect that ordinary modern bacteria had worked their way into his broth, Dombrowski developed elaborate precautions to keep the invaders out (including germ-killing ultraviolet light, antiseptic solution, and gas flames), repeated a laborious process 180 times. In 86 cases the broth contained a culture of living bacteria which, Dombrowski is sure, could only have come from the ancient salt. Most of the bacteria were strains of Pseudomonas, whose nearest modern relatives live in the intensely salt water of the Dead Sea.

Some bacteriologists may still be skeptical. Bacteria can be enclosed in crystallized salt and stay alive. Only last week bacteria were reported that had lived in Antarctic ice for 44 years, since the Shackelton Expedition of 1917. But living in salt for 180 million years is an unheard-of feat. Dombrowski, nevertheless, has able supporters. Bacteriologist Georg Henneberg, head of Berlin's famed Robert Koch Institute, does not doubt that Dombrowski extracted living bacteria from the interior of solid blocks of Zechstein salt—though there is still a slim possibility that the salt was contaminated relatively recently by bacteria that entered the crystalline mass through microscopic cracks. To buttress his theory further, Dombrowski is examining salt from even older beds. Last month the University of Montreal sent him samples from Saskatchewan deposits that are 320 million years old. In 20 experiments he found eight strains of living bacteria. Now he has broadcast a worldwide appeal for samples of pre-Cambrian salt 750 million years old, hopeful that he can find still more primitive germs.