Claude Ephraim ZoBell, 84; Father of Marine Microbiology

Claude Ephraim ZoBell, whose discovery of organisms living at extreme ocean depths earned him the title “father of marine microbiology,” has died of cardiac arrest. He was 84.

ZoBell, who died Monday at Scripps Memorial Hospital in La Jolla, discovered not only 65 species of ocean bacteria but showed that microorganisms affect the formation of petroleum.

“Claude ZoBell’s contributions to marine biology and the ecology of the oceans is acclaimed worldwide, but less known was his devoted service to the scientific community,” said Edward Frieman, director of Scripps Institution of Oceanography at UC San Diego, where ZoBell had been on staff since 1932.

“His leadership in the field of marine microbiology drew many researchers from all over the world to his laboratory, and his generosity in directing younger scientists will last for many years into the future.”


ZoBell, a professor emeritus at Scripps since 1972, was the first researcher to recover and cultivate living organisms from ocean depths greater than 20,000 feet, said George Somero, chairman of the Marine Biology Research Division of Scripps Institution.

“Claude ZoBell’s discoveries that microbial life is possible in such extreme habitats as the deep sea opened entirely new vistas for later generations of microbiologists,” Somero said.

He kept the microorganisms living and reproducing in a laboratory at Scripps in steel tubes thick enough to withstand pressures 1,000 times greater than the Earth’s atmosphere.

His research also led him to conclude that life began not on the Earth’s surface but at the bottom of the oceans under tremendous heat and pressure.


King Frederick IX of Denmark awarded ZoBell the Galathea Medal in 1952 for successfully recovering living bacteria from more than 34,000 feet of water in the Mindanao Trench near the Philippines.

His other honors included the Oceanography Medal from the Soviet Union Academy of Sciences in 1958 and a U.S. Congressional Citation in 1972.

ZoBell’s early research at Scripps included discoveries that bacteria can cause oil to separate from marine sediments. He won a patent for the process in 1947, which ZoBell assigned to the American Petroleum Institute for free public use. His research has shed much light on how microbial action affects oil spills, Frieman said.

ZoBell published nearly 300 scientific papers and one textbook. He also founded the international Geomicrobiology Journal in 1976 and served as its editor until 1981.