Professor of Biology Colleen M. Cavanaugh loves bacteria.

She's especially fond of the organisms that live inside undersea tube worms, existing on sulphur filtering out of deep-sea thermal vents.

Now in her 16th year at Harvard, Cavanaugh, who came to Cambridge as a graduate student and was tenured last February, has spent most of her professional life studying marine ecology.

In graduate school, Cavanaugh spoke up during a colloquium to propose the theory that bacteria live symbiotically within tube worms, metabolizing chemicals to stay alive.

The implications of this idea proved far-reaching, and scientists are still studying such symbiotic relationships.

"By looking at synthetic systems, we can understand eukaryotic forms," Cavanaugh says.

Today, Cavanaugh and her 11 student research assistants--post-doctoral fellows, graduate students and undergraduates--are pursuing several interrelated projects, including the diversity of symbiotes within the vents and the ecology of the carbon dioxide-fixing enzyme RuBisco.

But Cavanaugh is always looking for new avenues of research.

"We have a zillion little projects," she says.

The professor personally presides over all activities in the Cavanaugh Lab and is present in every decision, students say. The atmosphere of scientific congeniality is notable.

"She is a very enthusiastic, involved person," says Benjamin C. Kirkup '96, who is working on a phylogenetic analysis of RuBisco in the lab. "She has her hand in everything and is on top of all aspects of the lab."

Kirkup praises his mentor's involvement in the projects of her students.

"She is very concerned about people falling through the cracks, and is not only concerned for the lab work and science but also for the education and career development of all the lab personnel," he says.

For her part, Cavanaugh says students are her favorite aspect of the University.

"The best thing is the students," she says. "The undergrads are just amazing."

Given the unusual nature of organismic and microbiology departments, Cavanaugh says her department--Organismic and Evolutionary Biology--is another major benefit of working at Harvard.

As part of her new position, Cavanaugh is preparing to move into a newly-renovated lab three floors above her current location. Her new quarters should be finished on the first of July, "but it will probably be in the fall," she says.

She has decorated the walls of her office in the Biological Labs with images of pandas--her favorite animal--and her three-year-old son, Matthew Cavanaugh Gschwend.

The other loves of her life--bacteria--are already well represented in the lab's test tubes.

Asked what she would do with her life given the choice, Cavanaugh looks puzzled and responds, "Well, this," indicating her scientific domain with a sweep of her hand.

Cavanaugh says she and her husband, Philip Gschwend, a professor of environmental organic chemistry at MIT, joke about winning the lottery so they could avoid the tedium of writing research grant proposals.