Imre Friedmann, who died on June 11 aged 85, led an international team of researchers which claimed, in 2001, that they had found "conclusive evidence" that Mars had once been teeming with life—3.5 billion years ago.
An expert on the microbial ecology of extreme environments, Friedmann led tests on a fragment from the potato-sized Martian meteorite ALH 84001 that had landed in Antarctica about 13,000 years ago and been retrived by scientists in 1984. The team discovered long chains of magnetite crystals that could only have come from living organisms.
The findings reignited a controversy which began in 1996 when NASA announced it had found the imprints of fossil bacteria in the same meteorite. Many scientists had argued that the biological traces were probably due to contamination by terrestrial bacteria. But Friedmann found the magnetite crystals embedded in layers of carbonate minerals and glass that could only have formed on the Red Planet. Furthermore the magnetite bacteria could not have existed in the Antarctic in the time since the meteorite landed, since they only live in mud. "No reasonable person," Friedmann concluded, could doubt the evidence of life on Mars.
Imre Friedmann was born into a large extended Jewish family in Budapest, Hungary, on December 20, 1921. He knew he wanted to be a biologist from childhood but by the time he reached the age to go to university, his path had been blocked by the anti-Jewish laws passed by the government of Miklos Horthy. Instead he studied science from books, carrying out chemical experiments in his mother's kitchen and working at home with a microscope.
In 1943 he was rounded up by the Hungarian military and sent to work in a forced labour camp in the Carpathians. One day in 1944, after he had spent several months in he camp, the camp guards disappeared and the cry went up that the Russians were coming.
Feeling that they had little option but to join the general exodus, the inmates joined hundreds of soldiers, civilians, horses and trucks fleeing the Russian advance. As he made his way west, Friedmann was approached by a Hungarian soldier who warned him that in the town just ahead, German soldiers were lying in wait for Jews. If he was caught, he would be whisked off to a death camp if not shot in the spot.
Hoping to escape this fate, Friedmann and a fellow inmate slipped off into a ditch, but they were spotted by a Hungarian army officer who forced them back on to the road and marched them at gunpoint towards the town. When they reached the town limits they were met by another column of Jewish forced labourers being marched along by a Hungarian officer: "Jews!" the officer said. "Come here, you are under arrest."
Friedmann recognised the "officer" as another forced labourer who had somehow managed to get hold of an officer's uniform. As ordered, Friedmann fell into line and the "guard" marched his prisoners to an empty cellar in an abandoned farm house where they hid in darkness for three nights as the Russian front swept over them. On the third day the cellar door opened and they were greeted by Russian soldiers who set them free after relieving them of their watches.
For the next two months Friedmann made the slow journey by foot towards Budapest, finding food and shelter where he could. The road went through the university town of Dubrecen where, even though the war was still raging, the university was preparing to open for a new term. He enrolled and spent a term there before continuing on to Budapest in the spring.
The city had been reduced to rubble and while Friedmann's mother had survived, most of the rest of his family, including his father, his brother, his grandparents and most of his aunts, uncles and cousins, had either perished in concentration camps or died of starvation and disease in the ghetto.
Friedmann escaped to the West in 1949 and finished his studies in Vienna. In 1951 he moved to Israel, where he became a professor at the Hebrew University. As a botanist he had studied seaweed and in Israel he began to look for algae in the arid Negev Desert. He found none in the desert soil but in 1961 an oil geologist friend brought him a piece of desert limestone with a green substance inside. At first he thought it must be some sort of copper compound but tests proved negative.
He scraped off a sample, looked at it under the microscope and saw that it was algae. He called these organisms cryptoendoliths and once he knew what he was looking for he found them everywhere. A millimetre or so beneath the rocky surface, the desert was alive with algae.
The scientific community at the time was not excited and his first presentation of his findings at an international botanical conference in Edinburgh in 1964 was largely ignored. However his research caught the attention of Lutz Weise, an algologist at Florida State University. Weise invited Friedmann to give a seminar at Tallahassee and in 1968 he moved there as an associate professor.
In 1976 he published an article describing cryptoendoliths living in the Ross Desert of Antarctica. His article attracted little attention at first because scientists were focusing at the time on the Viking landing on Mars. When, like the Negev soil, the Martian soil samples failed to reveal life, NASA turned to Friedmann's work and gave him funding which enabled him to collect samples and study micro-organisms throughout the world.
Suddenly cryptoendoliths became big news as Friedmann's rock-bound organisms renewed hope of finding signs of life on Mars. Microbes, it was thought, might have escaped the hostile surface environment by developing inside rocks. In 1997 he was one of a number of scientists given a sample of the ALH 84001 meteorite.
Imre Friedmann's wife and fellow microbiologist, Rosalie, died in 2005. He is survived by their three children.