November 7, 1995
Location: On Station 62 18' South Latitude x 57 14' West Longitude
In an area of the Bransfield Strait where measurements of high crust temperatures were
made in 1993.
Update:
We spent the day on station which means that we tried to keep the boat in the same
place for most of the day. This was a real challenge, because the winds were blowing at
40 knots for most of the day with gusts approaching 55 knots. It was a cold day to be
outside. Temperatures of about 20 degrees Fahrenheit mixed with snow and sleet made
it miserable to be on deck.
The coring crew was out on deck most of the day, testing a new sediment corer. Their
plan was to take core samples of the sediments in this area to look for evidence of
hydrothermal vents and to look specifically at the different layers of the sediment to get
and indication of what sort of geological factors caused these sediments to be deposited
by the sea in this area.
It took three trials to be successful with the corer. The first attempt was made from the
stern (back) of the ship. They attached the corer, which kind of resembles a long
stainless steel straw with weights on the top, to a large heavy cable and winch system at
the stern of the boat. The whole corer setup weighs about 1200 pounds and is about 15
feet long. A problem arose because the weight of the cable, at a depth of 2000 meters
where the samples were being made, was larger than the weight of the corer. As a
result, they had difficulty detecting when the corer had reached bottom, and the first
test was brought up with no sediment at all.
On the second attempt, they moved the corer to the starboard , (right) side of the boat
and used a much lighter cable and winch setup to raise and lower the corer. The setup
worked perfectly, and the scientists were able to determine when the corer penetrated
the sediments. As they pulled the corer out of the water from its journey of 2000 meters
in the ocean, the sediments shot out the end of the tube as soon as the corer hit the air.
Some of the scientists laughed, some yelled as a result of their frustration with the
devise. There wasn't much they could do until they got the corer back on deck.
Once on deck they were able to determine that a small pair of hinges at the bottom of the
corer that are designed to open after the corer has been pulled out of the sediment had
failed to close. This is what caused the sediments to fall out of the corer when it reached
the surface.
The team made some minor modifications to the corer and sent it down for the third time.
Just as on the second attempt, they were able to tell when the corer had pushed into the
sediments. This time the hinges had closed and when they pulled the corer from the
water, the core sample stayed intact in the corer. They brought the samples on board
and into the wet lab, where the scientists spent nearly 6 hours taking samples and
measurements of the various layers of the sediments. They also made observations of
color, texture and grain sizes, as well as features of the sediment which were unusual or
not typical for oceanic sediments. When the sampling process was done, the ten feet of
sediment had been cataloged into small sample bags, and small plexiglass boxes so that
future study of the samples could be made by them and other scientists back in the
states.
The OSU team continued to look for signs of hydrothermal vents and took water samples
using the CTD and made measurements for the presence of manganese using the ZAPS
sled in the same area that the cores were taken. At this location they did not find any
definitive evidence that vents were in this location, so the decision was made to move
later in the evening to the site of a ocean volcano that had been identified by scientists
mapping this area in 1993.
The plan for the night would be to take a number of water samples and ZAPS sled tests
to see if there were any hydrothermal vents active in this location.
As we made the move to the location of the volcano, a much welcomed change in the
weather followed us. The winds died down from 40 knots to about 15 knots. The air
pressure began to rise and the seas became much gentler. A noticeable change in the
stress level of the ship staff and scientists came with the calmer weather. The constant
motion and jarring of the wind and waves takes its toll on you throughout the day. Since
you are constantly moving and trying to maintain some since of balance, you attention is
always being distracted. It is like trying to do two things at the same time. In rough
seas, the seas take priority over science. With calmer weather comes a renewed
emphasis on the work at hand.
As I ended my watch and prepared to go up to sleep, I looked through the starboard
porthole in the computer lab. Due to the cold weather and snow, the porthole had frozen
to form a tunnel of ice and icesicles which formed an eerie frame against the moving ice
and sea. It had been a long and challenging day.
QUESTIONS:
MB & JB: There has been a question about women on the ship. As far as the ships's
crew goes, there is only one woman on the crew. She works in the ships mess. On the
support staff, we have two women marine technicians and one computer technician. On
the science teams, the University of Texas has two women and the Oregon State has
four. Although most of the staff is men approximately 1/4 are women.
cketjpet: The first animals that I saw in Antarctica were birds. They are usually with the
ship at all times. In calm winds the spend most of their time in the water. On the windy
days they spend most of their time gliding in the breeze along side the ship. The second
most common animals that I have seen are seals. They are pupping right now, but I have
not seen any young as of yet. The last type of animals that I have seen are penguins.
For the most part they are in their rookeries hatching young, and very few make it out
onto the ice where we are. Hopefully in a few weeks we will see more.
The temperatures here range from 18 to 38 degrees F. There is not a whole lot of
variation between daytime and nighttime temperatures. The wind is the major problem
when you are out on deck. A calm day has winds of about 10 miles per hour. On the
windy days the winds are 40 to 50 miles per hour.
In terms of seasickness, I was sick longer than I thought I would be. I personally was
seasick for almost two days straight. Since my initial bout, I have been just fine, even
though we have had some pretty severe seas. Others on the ship have gotten slightly
nauseous every time we experience a major change in the motion of the ship. I expect
that when we start our trip toward New Zealand that many of us will get sick again,
because we will be bucking some strong headwinds and the boat will be pitching rather
than the rolling that we experience mostly now.
MB on WASDILine: Greetings to all of the WASDI people. Thanks for your support and
questions.
Jennifer J: The ZAPS sled is a package of instruments which sample the water for the
presence of Iron, Manganese and Radon. The instruments are connected by a electrical
cable to the ship so that the scientists are able to record data being collected on
computers as the instruments sample the water for these elements. They are
parcticularly interested in the presence of Manganese, because manganese is a key
element that is found near hydrothermal vents.
The streamer is a 1200 meter bundle of wirers that are attached to special microphones
called hydrophones. The streamer is towed behind the ship at a speed of 4 to 5 knots.
There are large air guns which are pulled behind the ship in the water. These guns
produce sound waves which bounce off the layers of the ocean crust at different
speeds. The reflected sound waves are detected by the hydrophones on the streamer.
Special computer programs interpret the data about the reflected sound received by the
hydrophones and produce a picture of the layers of the earth's crust below the surface.
The Helium and radon which is sampled is dissolved in the water like carbon dioxide in
soda. The gas stays in solution in the water because of the high pressure and cold
temperatures at the depths the water is collected. The water is transferred to special
copper tubes once the water samples are brought on board. These samples will be
analyzed later at Oregon State. Some of the samples for radon are tested on the ship
using special carbon filters which absorb the gas, and then instruments on the ship are
used to determine the quantity of radon in the samples. There is not enough gas being
released for bubbles to be visible at the surface.
The primary mission of this cruise is to collect data and make maps of the ocean floor
looking for new evidence about volcanoes, plate tectonics and the geology of this area
of Antarctica. There is much to be learned. Everything about this area of the world is
still very new and exciting.
