Microorganisms in Antarctic Seas main content.

Let's Talk with Cornelius Sullivan about Microorganisms in Antarctic Seas

Part of Irma and Paul Milstein Family Hall of Ocean Life.

Cornelius Sullivan is a biological oceanographer. He has been studying ice-covered oceans for over thirty years; his investigations focus on the bacteria and algae that live in the very cold salty water below the layers of sea ice. Cornelius was honored for his work as the Director of the Office of Polar Programs at the National Science Foundation when a 100-square-kilometer stretch of the Transantarctic Mountains was named the "Sullivan Heights."

AMNH: Why should kids know about Antarctica?

Cornelius: Kids all over the world should know how the world works, because they have the privilege and responsibility of living here. Antarctica is a real place where dreams can take flight; children can think about it in imaginative and wonderful ways.

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

Cornelius: Act locally and think globally. Start with yourself. What you do as an individual matters Protect that for which you are responsible. That's the best foundation for affecting things on a larger scale. Also, kids should try to understand nature. There are so many remarkable things that we need to learn about: how the human body works, how the environment, and different ecosystems work... It is unending!

Field of Study Biological oceanographer–"I'm interested in how an ocean roof of ten feet of ice influences where plants and animals live and how they make their living."

Hometown Pittsburgh, Pennsylvania

Interests in Middle School "I was fascinated by living things. I collected all sorts of animals; snakes, turtles, possums, chipmunks. I had an aquarium as well.

Kids Two sons, thirty-one and twenty-nine; one daughter, fifteen

Number of Trips to Antarctica So Far Twenty-five, for several months each time

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

Cornelius: Fifteen percent of the world's ocean is covered by a thin, floating layer of sea ice; but it's the part of the ocean about which we know the least. It's important to understand how this piece affects our total global ecosystem. If we understand how the sea ice system works, we can predict how it may be affected by natural events or human influences. The greatest pollution of Antarctica is due to the reduction of the ozone layer. Another effect of human activity is the massive amount of carbon dioxide we put into the atmosphere, which is probably influencing the rate of global warming. The sea ice is dependent on certain temperatures, so any temperature change has the potential to influence the sea ice ecosystem. On a small scale, any ship that might go on the rocks and release oil around Antarctica would have a major, but local, influence on the sea ice habitat. We do know that sea ice helps to cool the Earth and keep oceans circulating. Sea ice forms from ocean water. When it freezes, a lot of the salt doesn't freeze. The water underneath the ice becomes very salty and very cold. It sinks to the bottom of the ocean and eventually moves towards the Equator, cooling the water and ventilating the Earth. This mass of sinking water powers the circulation of the world's oceans.

AMNH: You're a biological oceanographer, so you must study Antarctic marine organisms.

Cornelius: One of the things I study is the many tiny organisms that live in the very cold salty water below the sea ice off Antarctica. During the winter, the sea ice covers an area bigger than the entire continent of Antarctica–and Antarctica is already bigger than North and South America combined! This means that this ecosystem is the largest continuous habitat on Earth. This huge place is home to many organisms such as viruses, bacteria, algae, anthropods, isopods, fish, squid, penguins that rest on the surface and sometimes maintain rookeries there, seals that birth their pups on the surface and keep them there for several weeks until they learn to swim and, episodically, even whales. Bacteria and algae get the whole cycle of life started. I want to measure how much of this living matter exists in the Antarctic sea ice because it's the building block for all other life in that ecosystem. It's as though I were a farmer who wants to know what nutrients the soil contains in order to figure out how large a crop I could grow. These algae not only feed other Antarctic organisms, they also produces about 25% of all of the oxygen on the planet–so they are very important!

AMNH: How do you study organisms that live below ice?

Cornelius: We dive below the ice and make visual observations. For example, we spot algae because it turns the ice green, brown, and golden brown. We often go out on a research ship and collect ice cores by drilling samples from the sea ice. The algae in the cores make the ice look like the color of frosty root beer or iced cappuccino. We very carefully observe the conditions that allow algae to grow, such as water temperature, amount of oxygen, minerals in the ice, amount of light, and so on. We tag small ice cores that we replace and watch over a period of time. Then we bring the alg