The National Zoo's Antarctica Expedition is sponsored by the National Science Foundation's Office of Polar Programs.
All photographs depicting Weddell seals were taken under NMFS Permit No. 763-1485-00 issued under the authority of the Marine Mammal Protection Act.
All About Antarctica
Antarctica is truly an unusual place given to dramatic extremes that can seem other-worldly: It is the southernmost continent and the coldest; parts are so dry that precipitation has never been recorded; it has more ice than any other place on Earth. In short, it is the coldest, windiest, highest, and driest of all continents. It is also the hardest continent to get to and live on.
Despite the inhospitable nature of the vast Antarctic wilderness, it has long drawn explorers, adventurers and scientists with its siren song. There have been permanent settlements and research stations in Antarctica for a number of years, and a hardy breed of people have managed to figure out ways to cope with and work in the extreme conditions. Part of the excitement we are feeling as we prepare to go is the knowledge that we will be part of a special tradition and will be “walking in the footsteps of giants."
Viewed from above, Antarctica resembles a stingray completely surrounded by water, with its tail pointing toward South America and its head toward the Indian Ocean. With an area of about 14.2 million square kilometers, Antarctica is the fifth largest continent, smaller than South America but larger than Europe. If it were a country, it would be the world's largest after Russia.
Because of its polar location, high elevation, permanent ice and snow cover that reflects about 80 percent of incident solar energy, and absence of humid atmosphere, Antarctica is the coldest continent. Average winter temperatures range from -70 ° C to -50 ° C in the frigid interior, while summer averages reach a "balmy" -5 ° C to +5 ° C on its perimeter.
Antarctica's average elevation is a little over 2,200 meters, making it, on average, the world's highest continent. It is divided into two major regions—East (or "Greater") Antarctica and West (or "Lesser") Antarctica—by the Transantarctic Mountains of which Mt. Vinson is the highest point (4,900 meters). Despite being ice-covered, the interior rain-shadow valleys of this dividing range are some of the driest places on our planet.
About 99.5 percent of Antarctica is covered by ice. In some places the ice sheet is so thick (up to 4,800 meters thick) that its weight has depressed the underlying landmass. The ice sheet that covers Antarctica is very dynamic, at least at its edges. During the Antarctic winter the ice sheet expands into the ocean creating an ice cover than can be more than twice the area of that in summer. more
Antarctica's rocks are some of the planet's oldest, and some of its newest—those of East Antarctica are at least three billion years old while the volcanic rocks of West Antarctica are a youthful 700 million years old. Between about 600 million and 100 million years ago, Antarctica was connected to landmasses that have since become Africa, South America, India, and Australia in a vast super-continent called Gondwanaland. At times during this period, Antarctica's location was much farther from the South Pole and its climate much more moderate.
Plant and Animal Life
Fossil plants and animals—including ferns, petrified wood and fossil dinosaurs and marsupials—have been found in Antarctica that indicate its climate supported floral and faunal elements similar to those of other southern continents.
There are no trees and shrubs on the Antarctic continent and only two species of vascular plants ("higher" plant species) are found there—a species of grass and the Antarctic pearlwort. There are, however, about 350 species of lichens, more than 100 species of mosses, and possibly hundreds of species of algae, all living a very low-profile existence mostly near the continent's wetter and warmer perimeter.
Antarctica's native animals—those that live entirely on land—are all invertebrates and are small, most of them near-microscopic. Most eke out their existence in patches of exposed soil or rock crevices, but some are parasites of the birds and mammals that live on the ice sheet. There are no native terrestrial vertebrates on the Antarctic continent, but the ice sheet supports several species—and large numbers—of seabirds, penguins, and seals, including the Weddell seal, the focus of our research.
The Antarctic continent supports so little plant and animal life largely because due of its low temperature and lack of moisture. How then can the Antarctic ice sheet support so many birds and mammals? The answer is that while the continent itself is generally unsupportive of life, the surrounding waters are incredibly rich in nutrients and all the vertebrates living on the ice depend, to one degree or another, on plentiful resources derived from these oceans.