Colleen Cavanaugh

Colleen Marie Cavanaugh is an American academic microbiologist best known for her studies of hydrothermal vent ecosystems. As of 2002, she is the Edward C. Jeffrey Professor of Biology in the Department of Organismic and Evolutionary Biology at Harvard University and is affiliated with the Marine Biological Laboratory and the Woods Hole Oceanographic Institution. Cavanaugh was the first to propose that the deep-sea giant tube worm, Riftia pachyptila, obtains its food from bacteria living within its cells, an insight which she had as a graduate student at Harvard. Significantly, she made the connection that these chemoautotrophic bacteria were able to play this role through their use of chemosynthesis, the biological oxidation of inorganic compounds (e.g., hydrogen sulfide) to synthesize organic matter from very simple carbon-containing molecules, thus allowing organisms such as the bacteria (and dependent organisms such as tube worms) to exist in deep ocean without sunlight.

Early life and education Cavanaugh was born in Detroit, Michigan, in 1953.

Cavanaugh received her undergraduate degree from the University of Michigan in 1977, where she initially studied music but ultimately majored in ecology. She says her life changed direction in her sophomore year when she heard about a course in marine ecology at the oceanographic center in Woods Hole, Massachusetts. There, her work involved wading out into chilly waters to study the mating habits of horseshoe crabs, and she described herself as "[falling] in love" with the relaxed camaraderie and exchange of ideas between biologists, geologists, and scientists from other disciplines. Her Ph.D. dissertation, entitled Symbiosis of chemoautotrophic bacteria and marine invertebrates, was accepted in 1985.

Discovery of chemosynthesis in tube worms By one account, Cavanaugh was attending a lecture by Meredith L. Jones, curator of worms at the Smithsonian Institution, shortly after she began her graduate studies. Jones was discussing the giant tube worm, a creature lacking both mouth and gut, where the challenge was to understand how it survived. Jones mentioned elemental sulfur crystals within the worms gut; Cavanaugh states that "It was at that point that I jumped up and said, 'Well, it's perfectly clear! They must have sulphur-oxidising bacteria inside their bodies'". This was followed by elevation to assistant professorship in 1989, and associate professor in 1993. In 1995, she was granted tenure as a full professor "for [her] discoveries and her reputation as a teacher and mentor." for 17 years.

Research and outreach highlights Cavanaugh has continued to build her career on the study of hydrothermal vent ecology. Cavanaugh went on to discover similar symbiotic partnerships among Solemyidae clams living in shallow eelgrass beds and mudflats along the New England coast, and in shrimp near sub-sea springs in the middle of the Atlantic. Cavanaugh, who has been called "a scientific Captain Nemo." As reported in February 2000, Cavanaugh is the discoverer of a new species of deep-dwelling mussel in the Gulf of Mexico that shares its body with symbiotic bacteria that feed on methane.

Cavanaugh Laboratory The Cavanaugh Laboratory at Harvard works on a number of projects related to bacterial symbiosis in marine invertebrates from deep sea hydrothermal vents, methane seeps, and coastal reducing sediments. Researchers there have a special interest in characterizing the metabolic and genetic capabilities of symbionts, their evolutionary relationships with free-living bacteria, and the co-evolution of symbiont and host.

Awards

Fellow of the American Association for the Advancement of Science (1996)

Significant publications