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Colleen Cavanaugh Dr. Cavanaugh is a Professor of Biology in the Department of Organismic and Evolutionary Biology at Harvard University. Cavanaugh's research focuses on the ecology and evolution of bacteria, with special emphasis on symbiotic bacteria, which is associated with marine invertebrates that inhabit deep-sea hydrothermal vents and shallow reducing sediments. Cavanaugh's studies showed the major macro fauna at hydrothermal vents studied to date host symbiotic, chemosynthetic bacteria.
These bacteria use chemical energy obtained from reduced sulfur compounds to fix carbon, while photosynthetic organisms use light energy to drive carbon fixation. Colleen Cavanaugh grew up in Detroit. She never thought she would study marine biology and would make discoveries. When Colleen was in the second grade, she wanted to be a scientist; however, she did not know what would be her field of studies.
By the seventh grade, Cavanaugh became very interested in biology and ecology. Much later Cavanaugh said, I thought about working on the Great Lakes, and decided to major in biology at the University of Michigan. (Cromie) When Cavanaugh decided to look for a waitress job, suddenly luck intervened, and Colleen replaced a last minute dropout of undergraduate research program in Boston University. At that time, she did not assume that she would make such important scientific discoveries. In her sophomore year, Cavanaugh heard about a course in marine ecology at Woods Hole, Massachusetts. This course for Colleen became an event that significantly changed her life. In 1997, Cavanaugh received undergraduate degree.
She moved to Woods Hole where she worked at the Marine Biological Laboratory. Cavanaugh believed that a life of research and teaching would be ideal. At the beginning, Cavanaugh was studying horseshoe crabs; however, after two years of work in the Laboratory she became interested in bacteria. Cavanaugh was impressed with the bacteria's ability to live everywhere. As a first-year graduate student, she discovered what makes life possible in the depths of the sea where the sun never shines and where the ocean waters pressure of thousands of pounds on every square inch of an animals body. Giant worms, huge clams and mussels live in such conditions because of one-celled bacteria that live on and inside of them.
These bacteria can turn sulfur, methane, and other inedible's into organic molecules that their hosts feed on. Bacteria provide food for these worms and mussels, and it is their tool of survival under such conditions. Some people think life on Earth began in these deep, hot springs. Cavanaugh thinks, The idea makes sense because some of the oldest forms of free-living bacteria show signs of being heat-loving organisms. (Cromie) Cavanaugh became focused on the nature and evolution of the partnerships that allow these host-guest combinations to live in otherwise inhospitable places.
Cavanaugh discovered that they cannot survive without the food produced by its guest; and the guest cannot survive without a stable place to live. Cavanaugh found that the same kinds of partnerships exist among bacteria. She also discovered a new species of deep-dwelling mussel in the Gulf of Mexico that shares its body with methane-utilizing bacteria. (Cromie) Methane, or marsh gas, is of no use to the mussels until bacteria convert it to carbon. (Cromie) The shellfish then munch the bacteria. This fundamental research earned Cavanaugh an M. A. in 1981, a Ph.
D. in 1985, a Junior Fellowship in the Society of Fellows in 1986 - 89, an assistant professorship in 1989, then an associate professorship in 1993. (Cromie) Vent life that was discovered by Cavanaugh has raised many interesting questions about life on our planet. It is a very interesting to know how different animals adapted to live in harsh environments and how they adapted to survive. As we know, the majority of living things get their energy from sunlight. Plants photosynthesize, which makes them to depend directly on the sun in order to obtain energy.
Animals eat plants to consume energy and they depend on the sun. For many years people though that life without sun is no possible; however, Cavanaugh's research has changed this belief. Cavanaugh has found the source of energy that exists in the dark depths of the sea in 1980. Answering the question of the vent lifes energy source actually turned out to be relatively straightforward. (Zoo Goer) Cavanaugh was convinced that the giant tubeworm's had symbiotic bacteria was so strong that she persisted and got a sample of giant tube worm tissue from Jones.
Scientific community was stunned when Cavanaugh presented her research, which was based on the idea that tubeworm's did indeed harbor bacteria inside their trophosome cells. In fact, bacteria comprise the bulk of trophosome tissue. (Zoo Goer) Other researchers showed that the trophosome contained enzymes characteristic of sulfide-oxidizing bacteria that are not found in animal cells. (Zoo Goer) When it was discovered what tubeworm's lived on, Cavanaugh was not surprised to find that Solely velum had symbiotic bacteria within the cells of its gills. Subsequent research showed that the 10 -inch white clams from the Galapagos vent and most other vent mollusks also have symbiotic bacteria in their gills, which are unusually thick and fleshy. (Zoo Goer) Nowadays, it has been discovered that such symbioses exists in more than 100 species on our planet. These species are marine invertebrates, including the tiny tubeworm's, which were originally thought to subsist on food absorbed through their skin. All these species live in the sulfide-containing environments. Cavanaugh with other researches has also discovered that several marine invertebrates have symbiotic bacteria that get their energy from methane, which can be found in many environments from hydrothermal vents to cold-seeps, cold springs in the Gulf of Mexico and the North Sea.
These species include two mussels from the Gulf of Mexico, a hair-sized tube worm found off the coast of Denmark, and a mussel from a vent along the Mid-Atlantic Ridge. (Zoo Goer) The vent mussel is particularly of a great interest, because it can also have sulfide-oxidizing bacteria, which would allow the mollusk to use whichever energy source available at a given time. Cavanaugh says, Its unprecedented to maintain a stable symbiosis with two kinds of bacteria. (Zoo Goer) Cavanaugh claims, The ribosomal RNA framework has absolutely revolutionized the study and exploration of microbial diversity. From what Ive been able to determine so far, symbiosis arose many times over hundreds of millions of years of evolution. Today, there are tens of thousands of different bacterial species living in soil, water, and even thousands of feet below the ocean bottom, but weve only identified about 4, 000 of them.
Ribosomal RNA studies will give us a start in categorizing this dizzying variety of life, to find out what they do, and to uncover the relationships between free-living and symbiont species. (Cromie) When hydrothermal vents were discovered it became obvious that people still do not know all the secrets of our planet, despite a scientific progress of the last half of XX century. People do not know a lot about the life under water yet. The depths of the ocean remain largely unexplored along with the live that exists there. Colleen Cavanaugh made a significant contribution into the discovering the mysteries of our planet. She worked on marine biology onboard ships and in the laboratory for 12 years.
Nowadays, Cavanaugh passes on her knowledge to students in undergraduate and graduate courses about environmental microbiology, bacterial diversity and symbiosis. Sources: Cromie, William. Microbiologist-Aquanaut Colleen Cavanaugh Receives Tenure, web Zoo Goer: Life without Light, web The Microbial World, web web
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Research essay sample on Gulf Of Mexico Hydrothermal Vents
