Quarterdeck Volume 4, Number 1, Spring 1996
You mean Santa's at the North Pole?!
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 ceremony 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.
We spent most of our time crossing and recrossing the Antarctic Circumpolar Current (ACC), the world's largest and longest current. Unimpeded by continents, and only slightly inconvenienced 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.
The most prominent front, and the first to be noticed, was dubbed the Antarctic Convergence by Sir George Deacon in the 1930s, but is usually called the Polar Front these days. By the late 1970s, the Subantarctic front to the north was recognized as circumpolar. More recently, Texas A&M oceanography graduate Alex Orsi showed that a third front, the southern ACC front, is also a ubiquitous feature of the current. One of the goals of our cruise on the Knorr was to pinpoint the location of the fronts more precisely in this data-sparse region.
We confirmed that the southernmost front of the ACC turns northward after squeezing through a deep gap south of the Kerguelen Plateau near 85°E. Sophisticated tracer information was hardly required for this discovery because a line of nature's own tracers (icebergs) streamed continuously toward the north here, and then turned toward the east.
Our eastward transit between the end of our first line at 85°E and the beginning of the second one at 110°E was lengthened by more than a day when the Knorr was forced to retrace her track and head west and then north to avoid the dead end formed by the convergence of drifting ice to the north and permanent ice to the south.
There she blows!
Most of the science party was able to relax a bit during the three-hour transit from one station to the next, but four NOAA whale-watchers pulled the swing shift-they rested during stations, and manned the flying bridge when underway. Their job seems enviable in the tropics, but its appeal diminished considerably when several layers of survival gear were required to withstand the cold and wind.
They watched for birds, whales, and other wildlife any time the ship was underway during daylight. On the southern reaches of our cruise track, not only was it cold, but night lasted only four hours or so. Not even fog provided a break for the NOAA team-they were pressed into service as look-outs to watch for growlers, VW-sized bits of broken icebergs that barely break the surface but could easily break the ship.
Despite a reputation for teeming wildlife, these Antarctic waters were surprisingly barren. For several days, there were not even any birds in sight.
A highlight of the cruise was the pair of humpback whales that cavorted close to the ship for several hours during a Christmas Day station. The performance was dizzying; hoards of shutter-clicking humans raced clockwise, and then counterclockwise around the main deck frenetically composing shots of whales, sky, bulkheads and other scientists' backs.
On New Year's Day, we made our second excursion to the edge of the icepack, this time almost to 65°S. Clear skies and calm seas enticed photographic gear topside, once again proliferating the idea that Antarctic cruises are blessed with perfect weather. The truth is that half of everyone's photographs are taken on the same two good days.
With the closest Wal-Mart half a globe away, the stockings were hand sewn after several raids on the boatswain's locker and the ship's hospital. (Photo by Thomas Whitworth III)
Steve Rutz (foreground) helps snag the rosette after a hydrographic cast. (Photo by Thomas Whitworth III)
The first sample extracted from each rosette bottle is tested for CFCs (2 o'clock), followed by helium (4 o'clock) and CO2 (6 o'clock). (Sample takers circle the rosette counter-clockwise in the southern hemisphere.) (Photo by Steve Rutz)
The Southern Ocean officially begins at the Subtropical Front. The three fronts of the ACC diverge around the Kerguelen Plateau. Ice prevented us from crossing the southern broundary of the ACC at 82E.
Initially, all Antarctic icebergs are tabular but wind and wave erosion can produce some bizarre shapes. (Photo by Thomas Whitworth III)
This friendly humpback was not as wary of man as the rare Southern Right Whale. We were able to track a Right Whale for a few hours by following its distinctive double spout. (Photo by Steve Rutz)
A typical balmy day in the Southern Ocean. (Photo by Thomas Whitworth III)
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Last updated February 24, 1997