24 November, 1998
Tuesday November 24, 1998
Greetings from 9915 miles away from Flint Hill, Oakton, VA
After a typical humdrum start, working for 3 hours in the darkroom until 9AM, today quickly turned into a fabulous day that I will never forget! Because of a connection arranged for us by Sandy Calhoun and Ginny Figlar of the newspaper here, Betty Trummel (another TEA teacher) and I were invited to spend the day at Big Razorback Island, part of the crater edge of an ancient volcano which is now mostly submerged in the frozen sea. Here we were able to learn about and parcticipate in the long-term research that has been going on with Weddell Seals since it was started in the summer of 1968-69 by Dr. Don Siniff of the University of Minnesota. The seal group has a webpage which describes their research and has excellent recordings of the bizarre medley of sounds made by Weddell Seals. It also shows maps of the study area which includes parts of Ross Island near McMurdo which I have mentioned in previous journals. Check out their website at http://siniff3.ecology.umn.edu
So at 10:15 Betty and I bundled up for protection against the cold wind and rode off across the frozen Ross Sea on our snowmobiles. It was a spectacular, crystal-clear, blue-sky day. There was not a single cloud in the sky and there was no haze from air pollution. This continent is known to have the cleanest air in the world. This was quite different from your typical commute to school or work. The snowmobile didn't conk out on me this time and when we turned the corner away from McMurdo into the spectacular scenery that I have already mentioned so many times, the feeling of exhilaration and freedom was what all you students will feel at the beginning of Christmas vacation. By 11:50 we arrived at Big Razorback where we were warmly greeted by Don Siniff and 7 of his graduate students from the University of Minnesota who emerged from three little orange huts which is their home and lab on the ice.
LIFE IN A FIELD CAMP
What is it like to live in a field camp? The huts have no running water but they are kept warm and cozy by an oil stove. They use an outdoor outhouse for a bathroom. The wastes are collected in a barrel and returned to McMurdo for proper disposal. About once a week the researchers ride their snowmobiles into town for a nice hot shower and to check their e-mail and pick up supplies. Most field camps do not have this luxury. They have an electric generator to power their computers and lab equipment. They have a telephone for communication with McMurdo and hand-held radios for communication between themselves when some of them are in the field. The shelves are well stocked with pasta, canned foods, candy bars, beverages, and even Chips Ahoy cookies. They cook using a Coleman camping stove using melted snow as a source of water. And their kitchen hut (where 2 of the graduate students also live) has a picture window looking out across the ice at a superb view of Mt Erebus and a big iceberg that is frozen in the sea ice. Space is cramped. But the closeness to the wonderful, overwhelming wilderness of Antarctica all around you, separated by only a thin hut wall, where you can easily hear the wind whipping by and the weddell seals wailing, and where, when the generator is off and the seal pups and skuas are silent, you can sometimes sit still and in the calm air hear absolutely nothing....absolutely nothing....this must be an experience that is worth every inconvenience. The typical schedule of this team of researchers is to sleep in
until 9AM, then do various camp chores, and then get on with the research of the day which may continue until 10 PM. This research usually involves tagging individual pups and adults with numbered colored plastic tags that are inserted into the hind flippers so they can keep track of the movements and life history of invididuals when they see them again. (This is the same thing we do at Flint Hill with bird banding and cricket marking.) Other research involves taking small blood samples to test the blood for diseases, or epoxying radio-transmitters onto the backs of adult male seals so they can keep track of the bulls' movements and territories using a pair of tall, solar-powered antennae at the camp.
Then before bed, the researchers log the data from the day's work into the computers and finally "hit the hay" at about 2 or 3 AM, in broad daylight. Every three days, weather permitting, they go throughout their study area by snowmobile, censusing how many seals are in each location and especially where the tagged individuals are. During field work all the raw data is carefully recorded in hand-held field data computers.
Mike Cameron, a PhD student who seemed to be the guy in charge, was an excellent teacher as he led us around the perimeter of Razorback Island describing the life-cycle of the Weddell Seals and the different types of research that are going on. He was repeatedly interrupted by our enthusiastic questions and by the behavior of the seals. Cute cuddly seal pups nuzzling milk from their momma's mammary glands, pups wailing and bleating to get their mother's attention, seals coming up onto the ice through holes or going the opposite direction, bizarre video-game-like sounds wafting up though the ice from seals singing below, the slushing sound of seal teeth scraping against ice to enlarge a hole or to make it more step-like, easier for the pup to exit the water, seals passing gas, and seals blowing bubbles in the water....these were all distractions that kept interrupting our fascinating lecture by Mike. Repeatedly I was distracted by the pressure ridge ice formations caused by currents and tides pushing the ice up against the land of Razorback Island forming beautiful sculptures of white and blue blocks. At one end of the island a huge, blue-and-intensely-white iceberg sculpted by wind and sun, was frozen in the ice. Everywhere I turned I saw scenery I wanted to photograph, with resplendently white Mt Erebus and its small plume of volcanic smoke always there in the background, so I clicked away as Mike patiently explained the life history of the Weddell Seal, the furthest south population of seals in the world.
Long-term studies of populations are very important, especially if the species studied has a long life span. Weddell Seals can live for at least 20 or 30 years. Since 1972, every pup born in the study area has been tagged, and over 120,000 individual sightings of the 13,500 marked seals have been logged. Here are some of the things that Dr Siniff's team has been able to discover over the years:
1. Individual seals do not stay in one colony year after year. They wander around breeding for a few years in one colony and then moving to another. Both males and females are just as likely to wander to different colonies. Individuals from outside the study area immigrate in, and individuals from this study area emigrate out and are sometimes seen tens of miles away. This tendency to ramble is very different from a lot of mammals and birds who have a set home range or territory. This helps to prevent these long-lived individuals from inbreeding and helps to keep the genetic variety in the gene pool high. 2. The breeding of Weddell seals is amazingly synchronous. In other words all the pups are born within a very short time of one another. Here near Mt Erebus the birthing time is around Halloween. Once, during a period of only two days, the seal team tagged 200 newborn seal pups. That is a pretty high number for such a short period considering that they only tag around 350-550 a year. This is very different from the Galapagos Sea Lions that I see with my students every few years on the Equator. In the tropics the environmental conditions are fairly constant all year so the sea lions can have pups at any time of year and still be able to find food easily. But here in Antarctica with the extremes of the cold, dark winter and the balmy, daylit summer when the food supply is abundant, it is important for the pups' survival to be born at the right time.
(QUESTION TO THINK ABOUT: Why is there so much more food present in the summer? Hint: Think of the melting sea ice, releasing ice-algae and micro-organisms, and their effect on the food web.)
3. The pups are 60 pounds when they are born! (WOW! Imagine being the mother giving birth to a 60 pound baby! UGH!) Then they quickly grow, nourished by the mother's extremely fatty and highly nutritious milk, so that by the time they are 6 weeks old they are almost full-grown and can go off on their own. (That's pretty fast growth! Much quicker than the normal growth rate of tropical Galapagos sea lions who may accompany their mother around for months at a time.) While the baby is growing fatter and fatter, the mother is growing skinnier and skinnier. For every pound the baby gains the mother loses 2 pounds. Sometimes it seems that the mother gets so tired of the baby's constant demands for food that she will just slide off the ice through the icehole into the nice quiet depths where she can get away from it all for a few minutes. I bet your parents sometimes feel like this too! When the pup is 3-4 weeks old the mother starts leading the pup
into the water. I wonder how the icy water feels to a pup the first time he goes in! Mike says the hesitant behavior and the startled expression on their face is quite comical. When the baby wants to climb back out onto the ice the mother may cut away the ice so the pup can climb up more easily, or she might even give him a boost with her head, but still some pups cannot get out and drown. We found one frozen pup floating in an ice hole. Maybe he was unable to climb out of the hole and drowned. We don't know.
4. After 6 weeks the pup is big and fat, you might even say obese. Then the mother leaves the pup for good. The pup sits around for awhile and he gets so hungry that he goes off to find food on his own. This is the hardest time in a seal's life. The highest seal mortality is in the first year of life. Over 1/2 of them die. This is true of most wild animals. But if they make it through this year they have a good chance of living a full lifespan of 20-30 years. Those who live to adulthood (5-7 years old) have a 98% survival rate.
The seals who make it through the first winter wander around for several years and then return to one of the colony sites at about 7 years old to have their first babies, one pup per female.
QUESTION TO THINK ABOUT:
Last year was a tremendous year for Weddell Seal birthing: 550 pups in an area where the average is 370. What explanations can you give about why so many were born last year? E-mail your answers to me and I'll e-mail you back.
After a lunch of fried Burritos with salsa we went by snowmobile around two other islands (Tent Island and Inaccessible island) to catch any seals whose tags had been broken so we could retag them.
Dan Monson, a wildlife biologist, called this cowboy science, and I can see why. He would walk up behind the seal, carefully (but quickly and forcefully) throw a large, black hood over the seal's head so it couldn't see, and then sit on the back of the seal. Sometimes the seal would buck like a bull for a few seconds but after a very short time the darkness would calm the seal down and Mike Cameron would put new tags on the flippers while Dan sat on the seal's back. This process is harmless to the seals. They just sit there as if nothing has happened when it is over. There is a little bit of blood oozing from the flipper but it quickly heals in the saltwater, and the seals don't even seem to notice the small cut. They are used to huge gashes inflicted by other seals in fights so this is just a little scratch to them.
Normally, according to the Antarctic treaty, wildlife cannot be disturbed in Antarctica. If you get so close to an animal that it moves away or even raises its head to look at you, you have disturbed it and technically you have violated the treaty. Mike, Dan, and the others all have permits to do their research allowing them to handle them in this way. Since we were helping them this day, we also fell under this permit and in order to check the conditon of the tags we often had to touch the wonderful velvetty fur on their hind flippers. What a great experience!
I learned tons and it was great to see
long-term research in action, to hear about what is being studied (and how), and about what is known and not known about the life cycle of Weddell Seals. Getting out of the lab to a spectacular place like Razorback, to work with such wonderful critters as Weddell Seals, to hear their bizarre range of vocalizations, to touch their velvetty fur, to look into their soulful eyes, to watch their behavior, to be thrilled by the majesty of a towering sculpted iceberg and masses of pressure ridges... .all of this was overwhelmingly mind-boggling, it was like a fantasy, and it reminded me of why I wanted to come to Antarctica. I was starting to forget why I came, but this excursion reminded me. It is a day I will never forget and I will share it all with my students. I hope that some of them will be inspired to do science either here or elsewhere as a result.
I hope you have a good day and do something good for someone.
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