Quarterdeck 4.1
Part 1
You mean Santa's at the North Pole?!
by Thomas Whitworth III
The stockings were hung by the chimney with care, and stuffed with treasures
like candy, freshly baked cookies and peanuts (in the shell!). But this
fireplace was fastened to the bulkhead with string and duct tape, and the
whole thing swayed slightly with each roll of the R/V Knorr.
There would be a few gifts exchanged; a short break in the normal routine
of the past twenty-five days. The next day was more than just Christmas,
it was hump day-halfway through the oceanographic cruise that began in Fremantle,
Australia on December 1, 1994 for the first leg of the Knorr's fourteen-month
Indian Ocean component of the World Ocean Circulation Experiment (WOCE)
Hydrographic Program.
The aim of the cruise was to get nowhere slowly. For every hour the ship
was underway, it was stopped on station for one and a half. The Knorr's
task was to take water samples along the southern parts of two lines (I8S
and I9S, in WOCE parlance) between Australia and Antarctica.
Expeditions to this remote part of the Southern Ocean are rare, and our
close station spacing of 30 miles was unprecedented.
At each station a 36-bottle rosette sampler is lowered to within ten meters
of the bottom, sometimes six kilometers deep. As the rosette is hauled back
toward the surface, the winch makes 36 brief pauses at different depths
to capture water samples. Meanwhile, greedy scientists begin to hover on
deck eager to lay claim to their small share of water.
Two hours later, some of the 360 liters of water has been transferred into
a variety of glass flasks, copper tubes, plastic vials, and glass syringes.
Most of it sloshes around on deck though-the residue of elaborate rinsing
and rerinsing routines designed to remove contaminants from sampling containers
and keep dreaded air bubbles from getting in.
Boots, yellow overalls, and frequently, hooded jackets made the watchstanders
collecting samples look like participants in some pagan cere-mony in a slow
procession around the rosette. Part of the ritual involved speaking in tongues.
Chants like "CO2 on bottle 14-3654" were intoned to the "sample
cop," who recorded the serial number of the flask containing the CO2
sample from rosette bottle #14 and insured that the Barium Guy did not draw
water from a bottle before the Tritium Guy had finished.
By the time we returned to Fremantle on January 19, 1996 we had completed
147 hydrographic stations and had collected water from more than 5,000 discrete
locations. Each sample might be the subject of as many as a dozen chemical
analyses.
Carnival Cruise Lines would not soon repeat our cruise track. We were about
as far from civilization as you could get, regardless of differing opinions
of Fremantle.
Follow that water mass
We spent most of our time crossing and recrossing the Antarctic Circum-polar
Current (ACC), the world's largest and longest current. Unimpeded by continents,
and only slightly inconven-ienced by islands and ridges, it flows eastward
around Antarctica and connects the South Atlantic, South Pacific and Indian
oceans.
The ACC carries about 130 million cubic meters of water per second-probably
not a meaningful measure for most of us. Next time you are in the observatory
on the 15th floor of the Oceanography & Meteorology Building, scan the
main campus of Texas A&M from Texas Avenue to Wellborn Road, and from
University Drive to George Bush Drive. Each side is about one mile long.
A square mile is about 2.5 million square meters. If the flow of the ACC
were diverted to College Station for just one second, you could watch the
water fill the campus to the top of the O&M Building. You might consider
bringing a snack-there is enough water in the ACC to continue that rate
for about 30 years.
The average width of the ACC in its 23,000-kilometer circuit of Antarctica
is about 1200 kilometers. Curiously, most of the flow is concentrated in
three bands about 100 kilometers wide. The edges of these bands of relatively
rapid flow, called fronts, separate surface waters with distinctly different
temperatures, salinities, and tracer concentrations.
[Continued...]
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Oceanography, Texas A&M University
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Updated May 27, 1996