O. Wirsen is a Senior Research Specialist in the biology
department at the Woods Hole Oceanographic Institution
in Woods Hole, MA.
holds a B.S. in Zoology from the University of Massachusetts,
and an M.A. in Microbiology from Boston University.
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
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Peter B. asks:
Do you ever find sunglasses down at that depth?
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.
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?
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.
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?
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
) Jackie M asks:
Are animals at one vent related to those at others? How
do they disperse?
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.
) Carly C. asks:
What do you like most about your work? What is frustrating?
What classes should one take to follow in your footsteps?
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.
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.