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Beneath the Sea

 
  Science Hotline  
Photo of Wirsen Carl Wirsen
Please e-mail your questions before May 28th Read the Answers

Carl O. Wirsen is a Senior Research Specialist in the biology department at the Woods Hole Oceanographic Institution in Woods Hole, MA.

He holds a B.S. in Zoology from the University of Massachusetts, and an M.A. in Microbiology from Boston University.

His research interests include Microbial degradation of organic matter in the deep sea; activity of marine bacteria at elevated hydrostatic pressure and reduced temperatures; equipment development for conducting in situ deep sea microbiological experiments; physiology and morphology of sulfur bacteria from oceanic thermal vents; physiology of thermophilic microorganisms from hydrothermal vents; physiology and ecology of marine bacteria; continuous culture techniques.

     

For links to this scientist's home page and other related information please see our resources page

Wirsen responds :

04/09/02 Peter B. asks:
Do you ever find sunglasses down at that depth?

Wirsen's response:
No sunglasses, but in the course of many ALVIN dives at many different locations I have seen the "human touch" on the deep sea floor. In particular, when we conducted a number of dives several hundred miles off the East Coast at depths of 3,600m there were many sightings of man made items. These ranged from unexploded WWII Hedgehog bombs to empty oil cans which stained the sea floor to nylon fish net material. So it can be disappointing considering the vast area of the ocean bottom to come across these types of things when we are working in such a small area. The time for organic materials to degrade and recycle in the deep sea can be extremely long and therefore the effects of pollutants will be long lived in this environment.

04/09/02 Sabre K. asks:
What was the condition (temp, pH, et c.) of the water around the lunch? Was it ever determined exactly what kept the lunch so fresh?

Wirsen's response:
While the actual pH of the water inside the open submersible sphere was not measured we can assume it was not significantly different from surrounding seawater (close to pH 8.0) since there was ample opportunity to have mixing over the 10 month period. The temperature would have been ambient at just about 2 to 3 C. The factors responsible for keeping the lunch materials from spoiling was a combination of high hydrostatic pressure (about 2,400 psi) and low temperatures. Under these conditions, microbial activity in the deep sea is generally much reduced compared to what would occur in shallow coastal waters. As an additional factor, if we just add a large amount of carbon containing material (e. g. bread, paper) such as was in the lunches, then microbial growth in the nutrient poor deep sea can also be rate limited by other essential nutrients such as N or P containing compounds.

04/09/02 Michael asks:
Do scientists know how many vents there might be in the world? Can you make an educated estimate? Have there been vents continuously in Earth's history?

Wirsen's response:
The Mid- Ocean Ridge (MOR) system stretches for some 72,000 km around the worlds oceans and all of the oceans water is re-circulated through these systems every 6 to 11 million years. While we don't know the exact number of vents along all the ridge axis we do know they occur in the Atlantic, Pacific and Indian Oceans and probably at other sites as well. While hundreds may have been seen, there are probably thousands we have yet to find. We find hydrothermal vents at the MOR due to the injection of magma from below, its solidification and cooling. New crust of the Earth is formed at the spreading axis above a magma chamber at a crustal plate boundary. The oldest crust in the oceanic basins is about 200 million years old, which means that since the earth was formed the process driving plate tectonics have produced about 20 times the volume of the present oceanic crust.

04/09/02 ) Jackie M asks:
Are animals at one vent related to those at others? How do they disperse?

Wirsen's response:
Animals of the same species but found at different vent sites are generally closely related and there are some cases where animals that are not of the same species (for example different types of tube worms) can be fairly closely related based on their genetic analysis. What has been found is that the relatedness of animals at a number of vent sites tends to cluster in what are referred to as biogeographic provinces. It is also found that animals of a similar type (e.g. mussels, tube worms) are generally related whether they are found at cold seeps or at warm vents. We have found that for certain sulfur bacteria carrying out chemosynthesis at vents that the same genetic species occurs at different vents in the Pacific, as well as being found at an Atlantic vent. Other bacteria and archaea are different from different vent sites, but we have still a lot of work to do to accurately describe the microbial ecology of these sites since we have cultured only a relatively few of the microbes present at any one site.

Animals from vents tend to disperse in larval stages (not adult stages), but we are not certain how far they can travel from any one spot to colonize another. Some biologists are studying this process by placing settling panels at vent sites to learn how fast and by what species they become colonized.

04/09/02 ) Carly C. asks:
What do you like most about your work? What is frustrating? What classes should one take to follow in your footsteps?

Wirsen's response:
In my particular situation I like most all of it. I work at a non-profit research organization which allows me to do what I like the most - hands on research. I don't have to do a lot of teaching, but can and have done it to some degree. I do research in the lab, plan and conduct experiments, go on cruises, help design and make equipment needed for our research, and write up and present our results. The major difficulty of research here at Woods Hole is that our funding has to all come from competitive research grants which we have to write and apply for funding from various government (and a few private) agencies. It seems I have to spend more time in the office and behind the keyboard than I used to. I loved it when we went to sea for several weeks and my only contact back to the lab or home was maybe one phone call (via a ham operator) a week. Now we have email, sat. phone, faxes etc. that keep us in constant contact with our labs. This has some good and some bad points in my opinion.

As far as classes go I encourage young students to take a diversity of classes as many discoveries of future careers are made by taking the right introductory class. Don't limit your options. Of course, they are those few that know they want to be a marine mammologist or a microbiologist or a geologist from very early on. To those, I would say take as many fundamental and advanced courses in your major field as possible. Often the marine aspects to a field can follow later on.

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