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...