Jannasch, Holger Windekilde (1927-1998)

German marine microbiologist

Holger Jannasch was a marine microbiologist who made fundamental contributions to the study of microbial life in the extreme environment of the deep-sea. His discoveries helped reveal a hitherto unknown type of bacterial growth and broadened human knowledge about the diversity of life on Earth.

Jannasch was born in Holzminden, Germany. After a short stint as a lumberjack, he returned to school. His educational experiences and a job as a warden at a coastal bird sanctuary stimulated an interest in both biological life and the ocean. These interests were pursued during graduate studies at the University of Göttingen. He received his Ph.D. in biology in 1955. From 1956 to 1960 he was an assistant scientist at the Max Planck Society. At the same time he was also a post-doctoral fellow at the Scripps Institution of Oceanography in San Diego, California, and at the University of Wisconsin. From 1961 to 1963 he served as an assistant professor in the Department of Microbiology at the University of Göttingen. He also held the position of Privatdozent at that University from 1963 until his death.

Visits to the Woods Hole Oceanographic Institution in the early 1960s lead to his joining the institution in 1963. He remained there for the remainder of his career and life.

While at Woods Hole, Jannasch proved to be a consummate mentor and educator. As well, he was a prolific researcher. His main interests were the growth of microorganisms in the sea, the existence of microbes at the low temperature and high pressure of the ocean depths, and the microbial processes taking place at hydrothermal vents on the ocean floor. Indeed, it was Jannasch who discovered hydrothermal vents.

Jannasch's research on the hydrothermal vents and their associated bacterial populations became classic papers that inspired other microbiologists to similar research. His discovery of sulfur-utilizing bacteria that support an entire hydrothermal ecosystem has had major implications for deep sea microbial ecology and may be of fundamental importance to providing insight into the origin of life on Earth.

Jannasch was also a seminal influence of the field of microbial ecology. He was a participating author on some 200 research publications. For these and other accomplishments in microbial ecology, a new microorganism was named for him in 1966: Methanococcus jannaschii. That same year Woods Hole established the Holger W. Jannasch Chair in recognition of his accomplishments.

Many other awards and honors were bestowed on Jannasch during his career. Foe example, in 1995 he was one of only a handful of non-United States citizens elected to the National Academy of Sciences.

See also Extremophiles