|
 |
|
March 17, 2003
A Floating Laboratory
The vessel that carried me to and from Palmer Station, the Lawrence M. Gould, is the outpost's lifeline to civilization. When not ferrying people and cargo, it is a research ship that makes scientific cruises. While I visit Palmer, the Gould and a crew of about two-dozen scientists, research assistants, and technicians make a month-long research cruise that extends about 200 miles south. About half way through the expedition, the ship passes near to Palmer Station. I am invited aboard to observe the research for a day. The visit begins in the wee hours of the morning. The ship is waiting for me not far off shore, eerily illuminated by running lights. I am ferried by Zodiac to the ship.
Robin Ross, the chief scientist of the cruise, welcomes us aboard. Ross and her husband Langdon Quetin have been studying the biology of ntarctica's Southern Ocean for more than a quarter century. Marine biologists say that the foundation of life in Antarctica is the krill, a pale pink organism in the same family as the shrimp. Almost every large organism in
Antarctica's austere food chain is dependent on krill, including penguins, humpback whales and many seal species. (The exceptions are mostly predators at the top of the food chain like killer whales and leopard seals and they eat the animals that eat krill.) The primary focus of Ross's work is the life of the krill.
The Gould gets underway at once. Ross takes me go to the galley for coffee, and briefs me on her research. Soon, the ship has reached its first sampling stop of the day. The scientist escorts me to a large watertight compartment.
The entrance to the room is a heavy steel hatch. It clangs shut behind me and I yank its big latch to seal it closed. The entryway, which reminds me of a bank-vault door is designed to keep seawater from flooding the Gould if the room is inundated in high seas. Now I am alone in the sealed, windowless chamber with a technician. I buckle a heavy harness around my waist and secure it to a nylon safety line. I am wearing a bulky jacket that doubles as a life vest, known as a float coat, in case I am washed overboard.
Suddenly, a garage-door-size hatch across the room swings open, flooding the room with sunlight. From my vantage point in the back of the room, I see the choppy blue sea, just 10 feet below. A hoist comes to life and lifts a big scientific instrument off the floor and through the opening in the side of the ship. Controlled by the technician, the hoist lowers the apparatus, which looks like a cylindrical steel cage just big enough to hold a person inside, into the sea. The gangly device is called a "rosette." The cage-like bars are actually a set of set of 22 upright plastic tubes for collecting water samples as it sinks to the sea floor. Attached to the frame is a device called a CTD, which measures conductivity, temperature, and depth continuously. (Temperature is the most important and basic parameter measured by ocean scientists. Conductivity is a way of determining the saltiness, or salinity, of the water.) There are also instruments to determine how clear the water is, the oxygen content and how much plant life is there. For the next hour or so the instrument-laden sampling platform gradually sinks to the ocean bottom thousands of feet below, making measurements and taking samples as it goes. Then the hoist slowly reels it up.
All day long and late into the night the Gould steams from stop to stop.
Between stops research assistants are processing the material brought from below. They add chemicals to water samples and monitor the results. They force other water samples through filter paper and count the microscopic organisms collected on the paper's surface. On some days the ship also collects krill and other organisms in nets, but not today. On the bridge a pair of researchers is surveying whales and penguins, petrels and other sea birds. One member sweeps the horizon with a pair of high-powered binoculars. The other records observations in a notebook. Their sightings will later be correlated with records of krill catches and ocean conditions to determine what animals are eating and why they go where they do.
Ross says a major goal of all this activity is to determine what factors control krill reproduction and growth. In bad years krill lay no eggs at all and the population stagnates. In good years they spawn more than once and the krill populations explodes. She wants to know what makes a year good or bad. The researcher says she has some clues, but more work is needed.
She says that sea ice, which covers tens of thousands of square miles of
Antarctic waters with a cap many feet thick during the southern-hemisphere winter, clearly plays a major role. Krill larvae feed on microscopic animals that live just underneath the ice. So in low sea-ice years there's probably less food for the krill. In recent years the average amount of sea ice in this region has been declining, possibly due to global warming. However, Ross says an earlier hypothesis that less sea ice always means fewer krill is not right. She now thinks the timing of the annual advance and retreat of the ice is a critical factor. She also thinks that in certain areas, where ice extends way beyond where krill live, reduced ice has no impact, whereas in other areas its impact is significant.
At some point during my stay on the Gould, I take a nap in the ship's lounge. Off-duty crew members are in the middle of watching one movie when I doze off. When I awake other crew members are watching another flick.
Then it's time to go. We're near the station again, and almost twenty-four hours after I arrived, I'm ferried back.
Read the March 14th entry
Read the February 14th entry
Read the February 10th entry
Read the February 6th entry
Read the February 5th entry
Read the January 31st entry
Read the January 27th entry
Read the January 22nd entry
Read the January 17th entry
Read the January 14th entry
Read the January 13th entry
Read the January 9th entry
Read the December 29th entry
Read the December 23rd entry
|
|
