A WEB PAGE DESIGNED FOR MIDDLE SCHOOL STUDENTS IN NEW HANOVER COUNTY, NORTH CAROLINA

 Dr. Steve Emslie, Associate Professor
Department of Biological Sciences

Where is Antarctica and how do you get there?

    Look on a map and find the Antarctic continent and the South Pole. People unfamiliar with geography often confuse the Antarctic with the Arctic and the North Pole. However, notice that there is no continent at the North Pole, only ocean. In addition, people often believe that polar bears are found at the South Pole and penguins at the North Pole. This also is false--penguins are found only in the Southern Hemisphere and only five of 17 species breed in Antarctica. Other species occur in Australia, Africa, and South America. Polar bears are found only in the Arctic regions of northern Canada and Europe.

Map and routes for Peninsular or continental research

   Once you find Antarctica on the map, note also that there are really two parts to the continent: the western part which includes the Antarctic Peninsula, and the eastern half of the continent divided at the Ross Sea. The Peninsula is the closest part of Antarctica to South America. The southern tip of South America includes two countries, Chile and Argentina, and the borders of these two countries cross through a large island, Tierra del Fuego (Land of Fire--named so by early explorers who saw all the native people's campfires along the coastline from their ships). At the south side of this island, in Argentina, is a small city, Ushuaia. This city is a port town for many ships, including fishing vessels, tour ships, and research vessels. In fact, Charles Darwin stopped here in his famous exploration on the Beagle in 1831-1836.

   Travel to other areas of the Antarctic usually departs via Australia or New Zealand.  To reach the largest U. S. base, McMurdo Station on Ross Island in the Ross Sea, scientists fly from Christchurch, New Zealand.  It is a long flight, approximately 12 hrs, and if the weather turns bad at McMurdo when enroute, the plane must turn back.  Though I have traveled to Antarctica and McMurdo Station in a previous expedition, this year my student and I will be going by ship to Casey Station, one of the Australian bases, on the east side of the continent.  There is no airstrip at Casey, so the ship is the only way to get there. We will depart from the port city of Hobart, Tasmania, a large island that is just south of Australia and part of that country.  Make sure you find this on your maps to see where our voyage begins. We are scheduled to depart on this voyage on 17 December and it will take ten days to reach Casey Station. So, we will have Christmas at sea this year. 

Scientists and research in Antarctica

    At present, there are 44 research stations in the Antarctic representing 18 countries. These stations are operated year-round, but most activities occur during the summer (November through February, opposite of our summer). Besides these stations, there also are numerous field huts and camps that are used only in the austral summer. Antarctica is not owned by anyone. All countries with bases have signed the Antarctic Treaty, established in 1961, in which it is agreed that this continent is to be used for peaceful purposes only and no territorial claims are recognized. In addition, no military operations are allowed, waste disposal is prohibited, and each country has the right to inspect another country’s station. To date, 45 countries have signed this treaty.  The treaty works well--scientists from different countries cooperate and work together. It is an international community.

Dr. Emslie and his research

   My research in Antarctica is focused on penguins and climate change. Specifically, I want to know how penguins have responded to natural climate change in the past so that we can better understand how they will cope with current global warming.  For example, in the Antarctic Peninsula alone the average winter temperature has increased by 4-5° C over the past 20 years, even though the average global temperature over that same period has increased by only about 0.5 to 1.0° C.  This difference in temperature change indicates how sensitive the Antarctic, and in fact most high-latitude regions including the Arctic, are to global changes.  In fact, the Antarctic is our 'canary in the birdcage' for what is happening to our planet as it warms.

    To study the past record of penguins, I search for abandoned colonies or places where birds used to concentrate on land to breed. I excavate into these colonies, like an archaeological site, because they often contain a wealth of information on the species that used to breed there, what they ate, and when they abandoned the site. From the sediments, I recover organic remains that are well preserved in the cold climate. I find bones and feathers from penguins, usually chicks, that died on the colony sometime in the past. I cannot determine how they died, but on modern colonies there always are some birds that die from disease, starvation, or predation. Their bones, however, can be identified to species and tell me if the former colony was occupied by Adélie, Chinstrap, or Gentoo penguins, three of the more common species found in the Antarctic Peninsula.  However, it is the Adélie penguin that is most abundant in Antarctica and is found in some of the coldest regions all around the continent. Thus, this species is the best for looking at how penguins have responded to climate change in the past.

   Once I have determined which species' remains I'm finding in the sediments, I also careful sift through the sediments to see if I can recover any evidence on the former diet of these penguins.  Usually, the sediments preserve hard parts of prey, including bones of fish, otoliths (fish ear bones) that can be identified to species, and squid beaks. These squid "beaks" are a chitonous mouth part that looks like a small bird beak. They also preserve well in the sediments and can be identified to species.  Although Adélie penguins also eat krill, a shrimp-like crustacean, this species has no hard parts so no evidence for it can be found in the sediments.  In excavating these abandoned colonies, I have found hundreds of fish bones and otoliths that indicate what the penguins were eating in the past.

   How old are the sites?  I can determine this by obtaining radiocarbon dates on bones or other organic remains I recover from the sediments.  This laboratory process gives the age of the bones, or how long ago the bird died, with an accuracy of within 50-100 years. When I date a series of these bones from all layers of the sediments in one colony, I can get an approximate time as to when the colony was first occupied and then abandoned.

   Did climate change play a role in why the colony was abandoned? This is one of the primary questions I'm trying to answer. To do so, I must compare the time of colony occupation with the climate record. We know how climate has changed in Antarctica from ice cores in glaciers. By drilling into the ice, scientists learn about past temperatures. Tiny air bubbles trapped in the ice when it formed hundreds or thousands of years ago can be analyzed for the chemical composition of the ancient air. These chemicals tell us if climate was warmer or cooler in the past compared to today. It is quite an accurate technique and I can use the climatic information in comparison to the occupation history of the abandoned colonies. So far, I have found that there is a good correlation between climate change and penguin occupation of certain regions in Antarctica.  For instance, warmer temperatures in the past compared to today resulted in abandonment of Adélie penguin colonies in the Antarctic Peninsula.  This region is experiencing a decline in this species today with the current warming trend. Thus, I can now predict that if the current warming trend continues, we may see an abandonment of the peninsula by this species over the next 20 to 50 years.  However, in the Ross Sea the opposite has occurred. There, it's so cold (colder than in the peninsula) that a warming trend that occurred from 3000 to 4000 years ago actually aided in the expansion of Adélie penguins in that region.  Mainly, the warming opened ice-free terrain along the coast there that gave penguins new areas to occupy. So, the response by penguins to climate change will differ depending on the local environment and average annual temperature.

    My research this year will take me to a new area of Antarctica where I have not yet collected any data. So, I do not know how old the penguin colonies will be or what story they will tell in terms of the impacts of climate change to that region.  There will be lots of Adélie penguin there, so I will be able to sample the active colonies as well as abandoned ones in the same region.  I'm looking forward to seeing what we find.