Logbook
August 26, 1998
Contents:
Today's Science News
Participant Perspective
Logbook from Teacher at Sea
Question/Answer from shore to sea
August 26, 1998
(photo (NOAA):Scientist Bill Chadwick, Bosun Matt Ofsthus and AB Patrick Quinanola (front to back) prepare the transponder (yellow sphere) for deployment.)
Science activities:
Dropped the transponders (8 of them)
and calibrated the transponder nets (3
separate nets: north rift zone, ashes, and south rift zone).
(See NeMO map for these areas). Looks like we will
be done with the calibration by late morning, then if all goes well we will be
ready for our first
ROPOS dive. Plans call for
SUAVE to be aboard the first dive
collecting samples.
Listing of all Science News postings
Personal Perspective:
Bob Embley, Chief Scientist
Hi Everyone,
I'm Bob Embley, Chief Scientist of the first
NeMO expedition. As I write this I
can't help reflecting on how much has changed in oceanography since my first
expedition 32 years ago. My first cruise on the VEMA in 1966 circled the North
Atlantic taking samples and measurements over thousands of miles during the
course of almost 6 months. Over the years there has been a steady increase in
complexity of the tools that scientists bring on board research vessels in
parallel with the sophistication of the vessels themselves. The
RON BROWN is
one of four state-of-the-art oceanographic vessels built in the 1990s with has
capabilities almost unheard of 30 years ago. As an example, it can hold station
over a spot on the seafloor with an accuracy of about 5 meters (~16 feet)! In
1966 we were fortunate at any given time to know our position within about half
a mile!
You're probably wondering what a "Chief Scientist" does on an expedition like
this. First, I should say that this is probably the most complex expedition
I've ever been involved in. My colleagues and I have spent the last two years
preparing for it! First, we had to develop the NeMO concept. Then we had to
write "proposals", wherein we presented our scientific ideas and requested money
to support the research. After that came the task of ensuring that we had
access to both the RON BROWN and the
ROPOS at the same time. So really the job
of chief scientist starts long before the cruise begins. Now that we're at sea,
I'm the primary contact person between the scientific party, the ship, and the
ROPOS group. My job is mostly coordinator of the science program, making sure
that everyone has a good chance to accomplish the goals stated in their
proposals. Since there are 33 in the science party (the most I've ever been at
sea with previously was about 25), this can be an interesting experience! In
addition, I have my own scientific goals which are aimed at a better
understanding of how mid-ocean volcanos form and interact with the ocean.
Tonight we are laying in "transponders", which are sound-emitting beacons placed
on the seafloor to provide ROPOS with its location while its operating on the
seafloor. Soon after we complete that sometime tomorrow afternoon, ROPOS will
descend to the top of Axial Volcano for the first time. In February, I was on
the
first cruise to the site on the research vessel
WECOMA after the
"event".
We measured large temperature anomalies in the water overlying the volcano but
could not visit the seafloor. The brief view I had of the
site in July from
the porthole of the submersible
Alvin revealed a volcanic landscape covered in
places with large areas of bright white bacterial mat and warm water gushing
from uplifted slabs of lava. Now we are poised over the volcano with ROPOS,
whose lights, cameras, and specialized instrumentation will bring this unique
group of biologists, microbiologists, chemists and geologists to this unique
environment for the the next several weeks. Even though the ship will not move
more than a few miles, I'm sure this journey will take me to at least as many
interesting places as I visited on that first expedition more than 30 years ago.
All of us out here on the RON BROWN are looking forward to sharing this journey
with you.
Bob Embley
Listing of all Perspectives postings
August 26 - 0800 hours
360 degrees around the ship, nothing but water. No land anywhere. That's a
strange feeling for those of us who spend most of our lives strolling around on
solid land. Speaking of solid land, let me give you just a little background on
where we are going and why we are going there. People who live along the west
coast of North America, at least those who live north of California, are just
becoming aware of the very real potential for a huge earthquake in this area.
There is plenty of evidence of such earthquakes in the past, and its been
several hundred years since the last one. Directly under our ship is the
Axial
Volcano. It is part of a huge and complex system of geologically active areas
called
mid-ocean ridges. Axial Volcano is producing new ocean floor, and in the
process is setting up a strain in the oceanic crust that will eventually drive
the leading edge of the ocean crust under North America. The result could
easily be an earthquake that would exceed 8.5 on the Richter Scale. We are here
to try to better understand that process. We are also here to try to understand
more about the biology, chemistry and physics of these vent systems.
1600 hours
We just deployed one of the first and most important scientific instruments. It
is the transponder. The transponders are the scientist's eyes and ears on the
sea floor. Transponders tell the scientists exactly where ROPOS is at any time.
This is absolutely essential in order to keep the multi-million dollar device
clear of the many dangers that lurk in the dark waters of the vent area. The
external surfaces of the ROPOS show a fair number of dents and scrapes that
attest to earlier close calls.
The transponder is a relatively simple piece of equipment. A radio transmitter
and receiver are placed inside two amazingly thin glass hemispheres.
(note correction later on
9/8 teacher log...not "radio"!) Some of
the air is pumped out of the sphere. This holds the two halves together. A
plastic cover then protects the whole sphere from bumping into solid objects on
the deck of the ship while the transponder awaits deployment. A transducer
attached to the top of the whole structure emits and receives radio signals at
frequencies that are different for each transponder. Another transponder
attached to the ROPOS cage and a slave unit attached to the ROPOS itself
constantly send signals back and forth. By simple triangulation (similar to the
way earthquake epicenters are determined by seismologists) the scientists are
able to locate the ROPOS and direct its movement over the ocean floor.
Hopefully as early as Friday or Saturday we will begin to see high resolution
color video shots direct from the vent zone. I encourage all students and
teachers to link to the ROPOS web site to find further information about this
phenomenal piece of engineering. We will be taking a closer look at the ROPOS
as well as the data and samples it collects throughout the voyage.
I should mention that I personally lost much of today after two seasickness
pills put me into the ozone. I was not alone. Many experienced ocean people
were green around the gills. For most people the symptoms last one or two days.
I vote for one! There is a price to be paid for being on the cutting edge of
marine science. It is a price worth paying. Beginning tomorrow I will be
spending four hours each day helping scientists in the labs. Check back with
this site to see what new discoveries are hidden tonight on the cold sea floor
1400 meters below the Ronald Brown.
Gene
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