Let's Talk with Stephanie Shipp about Glaciers, Sea Ice, and Life on Antarctica

Stephanie Shipp studies glacial geology and investigates how the Antarctic ice sheets have changed over the course of the last ice age (starting about 20,000 years ago) until today. Her work takes her all over the place, including two weeks a year at the American Museum of Natural History in New York City, her office at Rice University in Houston, Texas, and Antarctica. What's Stephanie's take on kids and Antarctica?

Why should kids know about Antarctica?

Antarctica has so many connections to the globe in terms of climate and history. Antarctica also holds more ice than any other location; we need to find out what that means to us. Also, Antarctica is still very much a mystery, and I love that!

How can students everywhere be good stewards of our least known continent?

Students should be aware that their decisions and behavior influence Antarctica and the entire global system. The more they learn about this system and how we can best be part of it–and we ARE part of the Earth's system!–the wiser their decisions will be.

AMNH: What's so important about your field of study in Antarctica?

Stephanie: Glaciologists consider one ice sheet, the West Antarctic Ice Sheet, to be potentially unstable. If the West Antarctic Ice Sheet were to break apart, it would release enough water to raise world sea level by about six meters. Think about all of the people and industries who would be directly affected if the coastline were eighteen feet higher than it is now! In my work, I'm trying to understand how the Earth's system has changed through time. When we look at changes in Antarctica, we see changes in other places. When the ice sheets were larger during the last ice age, the global ocean level fell, some land regions on Earth got drier, some land got wetter, and Earth's temperatures cooled. Now we're exploring what may happen if the ice sheet gets smaller. How fast did the West Antarctic Ice Sheet change in the past? Why? Answers to these questions may help us predict what could happen to the ice sheet in the future.

AMNH: How do you study deep sea vent ecosystems? What are you looking for?

Stephanie: I use my license as an ecologist to investigate many kinds of issues at vents, including the distribution pattern of vent species: which species occur where and why; food web relationships (who eats whom); and functional anatomy–how particular structures of a species are adapted to the environment. Because vents are so different from terrestrial and shallow-water ecosystems, and are fueled by chemical energy and chemosynthesis rather than photosynthesis, the study of vent ecology allows us to discover which ecological "rules" are universal, and which might be specific to chemically powered ecosystems.

AMNH: How do you look for answers?

Stephanie: Right now I'm analyzing data I collected from Antarctica's Ross Sea, to try to understand when and why the ice retreated from there starting about 20,000 years ago. The exciting part is that as we answer initial questions, we end up asking more questions, and all of our questions become more focused. Answering these more focused questions enables us to understand the details of the global climate, sea level, and oceanographic systems.

AMNH: How do you collect data from the Ross Sea?

Stephanie: I work on a research vessel to collect images and samples of the sea floor. I use a "piston corer." The piston corer is essentially a ten-foot-long hollow tube; we lower it into the sea floor and pull it back filled with sediment from beneath the sea floor surface. The sediment inside the core is in layers, with the youngest layers on top. We can study the layers to understand how the sea floor environment might have changed with time, because different layers record different information.

AMNH: For example?

Stephanie: If a glacier was present at a location in the past, it probably left a sediment layer of till–a poorly sorted mix of gravel and sand and mud. If a floating ice shelf later covered that same area, it probably left a layer of mud on top of the glacier's layer, maybe containing fossils of mollusks and microscopic animals. Once the ice shelf retreated, the open ocean covered the sea floor. It, too, has a signature deposit of a particular material, a mud that's green because it contains the chlorophyll of lots of microscopic algae called diatoms. Core samples can be dated, so we can tell when these various changes occurred.

AMNH: Are all the data you collect from actual sea floor samples?

Stephanie: We also collect images of the seafloor using sound waves. Some of the equipment, like side-scan-sonar, uses high frequency sound waves that don't have enough energy to go into the seafloor; they bounce off the seafloor surface. The equipment that receives this signal produces an image of the sea floor that looks almost like a black-and-white photograph. We can see features left behind by the glaciers, like long furrows carved by the base of the ice sheet. We also see "curlicues" on the seafloor surface, which are marks made when icebergs get stuck on the bottom and cut a path in the sediment as they move along. We interpret these images and map the features to determine how far the ice sheets extended during the most recent ice age.

AMNH: Describe a typical work day in Antarctica.

Stephanie: On the boat I work in twelve-hour shifts, twelve hours on and twelve off, for about thirty days. Usually there's a lot to do during the off time, like planning the next core sample sites and interpreting the information we've collected. It's tiring, but fun.

AMNH: How do you pick the sites where you collect core samples?

Stephanie: We work by making a best guess about how far the ice sheet might have expanded, looking for the spot where its edge would have been. We use data from earlier seasons to help us narrow down the region. Then we gather more seismic and core information, draw new conclusions, and refine our game plan. Often there are surprises, and sometimes real difficulties. One year the sea ice was so thick that we couldn't reach a certain region all season. It's important to have a backup plan when you work in Antarctica, because Nature often intervenes. Another year we encountered unexpected formations on the bottom of the sea floor, which we interpreted as drumlins–teardrop-shaped hills sculpted by the flow of the ice sheet. They tell us about the conditions at the bottom of the ice sheet, and also the direction of ice sheet movement. This changed our whole perspective about that region.

AMNH: Besides having to be prepared for surprises, what do you like about working in Antarctica?

Stephanie: The best part of my job is the other people. In Antarctica there is an incredible team working together for a common goal. I love the back and forth of the brain-storming sessions and the discussions, when we think about problems and toss out ideas. I also enjoy the lifestyle of a geologist–visiting neat places; the casual way that we live and work in these places; the accepting community of people who value your thoughts and intellect. It's also a lot of fun. One particularly fun memory I have is of barbecuing on the ship. It was a weird sensation to be out in ten-degree temperatures cooking chicken and steak. You had to eat your food very quickly before it got cold! In the early 1990s we used a Norwegian research vessel called the Polar Duke, which was stocked with reindeer meat, which we barbecued as well. It was very good! And then of course, there's the landscape, which is fascinating. The first sensation I had of Antarctica was that it smelled so dry and dusty, I could smell it as soon as I got off the airplane. I'll always remember the beautiful sea ice "landscapes" as well. Then there are the storms–it's exciting to run into a big storm when you're working at sea. Actually, in the bigger storms, you don't work–you just tie, tape, or screw everything down and hold on.

AMNH: What about life lessons?

Stephanie: The most important lesson is that science is a process that everyone can use everyday. It involves getting information, analyzing that information, and drawing the best conclusions. It's not always about facts; it often has to be a best guess based on careful analysis. In our everyday decisions, just like scientists in their research, we have to be careful. There's so much misinformation or partial information on the news, in public debates, in magazines, that we need to ask good questions and get sound information in order to make solid decisions. Debate is part of the process. It does NOT mean that scientists don't know what they're talking about, though it often reflects a need for more data.

AMNH: What do you do once you get back home?

Stephanie: Its a long process. After each trip, we spend two to three years in the laboratory analyzing the information and sudying the core sediment.

AMNH: How did you end up studying glacial geology?

Stephanie: I was always thinking in terms of systems, like the system at the creek where everything had a particular niche, everything worked together. Then in ninth grade, I had a science teacher who was very dynamic and excited about what he was teaching. We called him "Uncle Bruce." One day he put up a simple black-and-white overhead projection of mid-ocean ridges, these giant rifts in the ocean along which new Earth's crust forms, and something about it got my imagination going. He showed how the new crust formed along the ridges, and how the old crust was buried where one continental plate dives under another. It seemed so neat to me that there was a connected system for making new crust and getting rid of the old. At that point I started to think about being a scientist. I started by volunteering at the Smithsonian Institute in Washington, D.C., as a junior in high school. That's where I met my husband, but of course we didn't get married until several years later. He introduced me to field and coastal geology. I participated in the entire process of science: designing a field study, collecting and interpreting the data, drawing conclusions, and publishing the results. I spent the summer of my senior year in Maine, working with a geologist. It was really fun to look at the landscape around me and on the sea floor, and try to create a story about why and how it got that way. I went on to the University of Maine, continuing to study coastal evolution; in Maine, where there were a lot of glaciers during the last ice age, coastal evolution is closely tied to glacial geology. I worked on the Maine coast every summer, where I was very lucky to work with Dan Belknap and Joe Kelley and be in the field collecting and analyzing data. There's no replacement for hands-on experience. Dan became my undergraduate advisor, and he really showed me the power and beauty of the scientific process. After that I went to Rice University in Texas to work as a lab technician for John Anderson, who was a terrific mentor. He always let me charge ahead and learn from my own mistakes, but was there to steer me toward opportunities for growth. It's a difficult balance. He took me to Antarctica on a research project, and this sparked my own interest in trying to reconstruct the history of the Antarctic Ice sheet.