10 March, 2000
The Seal People in Their Tower
72 15 s, 114 30 w
-7 C (19 F), 15 knot (17 mph) wind out of the southwest
Barometer 972 MB and dropping, steady moderate snow
Ship heading 320 @ 5 knots (6 mph)
100% ice pack coverage
Depth 476 m (1562 feet)
Once again I'm on the bridge in the early morning darkness, watching the snow in the spotlights, not the stars in the sky. The Nathaniel B. Palmer is in transit to Thwaites and Pine Island glaciers, but it is not a direct route. We're in heavy ice, occasionally backing and ramming. The crew picks the best possible path, which sometimes involves going around very large flows, or retracing our path. Occasionally the ice halts the ship altogether. When this happens, the slowing down and stopping occurs so gradually that it is hard to tell exactly when the ship has completely stopped. Then, just as gradually and smoothly, it starts to back up. Once in a while, the propellers hit a large chunk of ice floe. Then you hear and feel a distinct shudder.
When the ship is in heavy ice floes like this, it almost seems as if I could run along beside it, or at least ski. There are very few cracks I could not jump across. I'd have to stay away from the ship, though, because it breaks and overturns floes as it goes.
Answer to yesterday's question: Why are there fewer than 30 planktonic foram species, while there are thousands of benthic types? Planktonic animals float and move around with the water. The populations mix and a few dominant types survive. Benthic forams probably cannot travel more than a few centimeters in their lifetimes, so populations become localized. Also, the environment of benthic forams, nutrients and oxygen, for example, vary widely over short distances. Planktonic forams live in an environment that is usually the same for hundreds of kilometers in any direction, and several hundred meters vertically. Since the water they live in is always mixing and moving, they may move many kilometers in their lifetimes. They are adapted to a huge water mass, not a few square centimeters of bottom.
Since we are in transit, and a slow transit at that due to ice conditions, I have a little bit more free time on my hands. I took the opportunity today to go up to the ship's ice tower, and talk with the seal people.
The ice tower observation post is a little room three stories above the bridge. It is used sometimes by the crew to find ways to get the Nathaniel B. Palmer through dense pack ice. To get to it, you climb three ladders and go through a hatch. There is enough space for three or four people, and big windows all around. There is a little electric heater, and a couple of comfortable chairs. There are window ledges for binoculars, and to lean against if the ship is rocking. There is even a door and a little catwalk around the outside of the tower, if you need fresh air or want to take a picture. Best of all, there is some of the wildest scenery on planet Earth all around you, from horizon to horizon. One of today's pictures, the iceberg with the peak, was taken from the catwalk. The ice tower is definitely the top of the bottom of the world.
The seal people, Dr. Suzanne Hill and Dr. Brad Scotton, spend hours each day up in the ice tower watching for and counting seals, whales and penguins.
When she is not in the ice tower, Sue Hill spends most of her time in Redmond Washington. There she is part owner of a company and full time mother of three children, two boys eight and twelve, and a girl ten. She has been coming to Antarctica since 1982, when she studied Weddell seal parenting at McMurdo station, for her doctorate degree. She met her future husband there, and she's been back to Antarctica many times since. She says she comes because she likes to study seals, she likes Antarctica, and she wants to give her children something to aspire to.
She says, "This is beautiful. It's much more fun than hanging around the mall. You don't have to play games. You're respected for what you can do. There are lots of women who are respected scientists."
Her company makes several different products. One of these is a small, light radio transmitter that is glued to a seal's back, directly to the hair. Seals are big animals, and the little transmitter doesn't seem to interfere with their activities. When they shed their hair (molt) the transmitter falls off. Most amazing to me is that the tiny transmitters, with about the power of a flashlight bulb, transmit directly to passing weather satellites, and may do so for up to a year before the battery runs out, or the seal molts and sheds the device. The information sent up to orbit includes data like the depth of dives and time spent diving, and the temperature of the seal's surroundings. On a recent cruise of the Nathaniel B. Palmer, thirty of Sue's transmitters were glued to seals. They are now sending back data.
When Brad Scotton is not in Antarctica, he works at the other end of the world, as a wildlife biologist for the State of Alaska's Department of Fish and Game. Brad was an undergraduate there. He drove to Alaska four days after he got his high school diploma. He says he would have gone earlier, but felt obligated to spend some time after graduation with his family. He figured four days was enough. In Alaska he studies many different animals, including salmon, moose, caribou, bison, wolves and Dall sheep.
He first came to Antarctica in 1991, as an undergraduate in college. He lived in "fish huts" on the Ross Sea ice, studying Weddell seals. He says the fish huts were just like ice fishing shacks, enclosed sheds with a trap door in the bottom, which could be dragged over a hole in the ice for seal or fish research. The National Science Foundation paid his way through their R.E.U. (Research Experience for Undergraduates) program, which is still active. It is one of several ways undergraduate college students can get to Antarctica. Like Sue, Brad has been back to Antarctica several times. They are not here just for the fun of watching seals, penguins and whales. Suzanne and Brad are doing their research as part of a program called the APIS project. APIS stands for Antarctica Pack Ice Seals. It is a five year effort by several different countries to study Weddell, Crabeater, Ross and Leopard seals. Some scientists think that the populations of these seals have increased at the same time that the number of whales decreased, because both compete for the same krill food supply. APIS hopes to find out among other things how many of these seals exist, where they live, and if they stay in one area or move around the continent's shores. APIS wants to learn more about the relatively rare Ross seals, about which little is known. When they spot seals, whales or penguins Brad and Sue record the species, location, time and date, and angle below the horizon. They also note information about the type and size of ice floe the animals are on or near. They look for scars on seals, especially Crabeater seals.
A great number of Crabeaters have parallel scars about ten centimeters (four inches) apart. Sometimes these scars extend most of the way around their bodies. The explorer Shackleton thought that the scars were from killer whale (Orca) attacks, but they match more accurately the spacing of Leopard seal teeth. Whatever the predator, a lot of Crabeater seals must come very near death and survive.
While we talk, a Minke whale surfaces in a nearby lead, blows spray, rolls and plays, and dives. Brad records the event on his clipboard. An Emperor and two Adelie penguins also get noted.
The APIS project is interested in penguins, both for their own sake, and because these birds occupy the same part of the food web as seals. Both are krill eaters, and both have increased in numbers since whale numbers decreased. Ice information is important in the penguin research. Researchers want to know, for example if the comic little Adelie penguins purposefully choose, for example, large floes or floes with ice ridges. The Adelies may use the ridges to escape Leopard seals, or to shade themselves from the wind.
If Sue and Brad spot a group of seals, they decide if the floe looks safe for people to walk on. If it does, they may ask the ship to stop, so that they can examine the seals closely, and get a small DNA sample from each. They have promised to let me accompany them next time they go out on the ice. I've been watching seals from the ship, and I'd really like a chance to see some close up.
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