Explorers and scientists from the United States have been coming to Antarctica since 1830, when James Eights became the first U.S. scientist on the continent. Today some 4,000 scientists from 28 different nations flock to Antarctica during the continent’s summer season, which is winter in North America, for the chance to conduct experiments that cannot be reproduced anywhere else in the world. About 1,000 scientists will spend the winter here. Women such as Yen are roughly 30 percent of the scientific and support workforce.

Numerous scientific discoveries of global significance have been made in Antarctica, and the U.S. Antarctic Program, part of the National Science Foundation (NSF), supports research on the continent, including Yen’s, to make sure that these discoveries continue.

A key mission of NSF’s Office of Polar Programs is to understand Antarctica and its ecosystems, to understand the region's effects on – and responses to – climate change, and to use the continent’s unique features for scientific research that cannot be done as well elsewhere.

Yen’s research fits all three goals: Plankton are at the bottom of a worldwide ecosystem, which is under threat by climate change. Plankton in Antarctica may feel the effects first, because of the area’s unique ocean chemistry.

Located on Anvers Island in the Antarctic Peninsula region and logistically isolated from the other stations, Palmer Station relies on the R/V Laurence M. Gould for transport of passengers and resupply from a port at the southern tip of South America. The R/V Laurence M. Gould provides onboard research support in marine biology, oceanography, and geophysics and can support science in other areas of the Southern Ocean.

Palmer Station is its own ecosystem. Staffed with scientists, doctors, cooks, and other support crew, the base has to be self-sufficient. This can mean unique, locally sourced meals such as omelets filled with krill from the day’s catch, an Antarctica specialty. Omelets filled with krill from the day’s catch are a typical meal.

“It’s actually a good source of protein,” Yen said. “Tastes like shrimp.”

The lab at Palmer Station is indoors, but the scientists are dressed as if they will spend the day on the ice. To mimic the planktonic environment – the coldest climate on Earth – the lab’s temperature is a constant zero degrees Celsius.

“All of us have been sitting in very cold rooms with these big parkas on to try to film the activity of how plankton interacts with their fluids,” Yen said.

Plankton come in a variety of shapes and sizes. Some make calcium carbonate shells to protect their soft bodies. Research has shown that plankton in acidic waters are not able to make shells as well as those living in normal waters. This threatens plankton health, as well as the health of species that eat plankton.

When plankton can’t form shells, they essentially have a flat tire. Plankton normally flap, paddle, and jet by propelling water. These methods of propulsion evolved in concert with the calcium carbonate shells. Harm the shell, and the plankton can’t move as well.

Yen’s team is in Antarctica to study plankton called pteropods, which are shelled organisms about 3 millimeters long. From the Greek meaning wing-foot, pteropods use their feet as wings for swimming.

Pteropods face the same threats from ocean acidification as other plankton. Research has shown that the acidity of continental shelf waters off the U.S. West Coast is dissolving the shells of pteropods. Yen’s team wants to see if the effect is more severe in Antarctica, where the water is much colder.

Inside the cold-lab, four cameras – each worth $40,000 – are trained on a small container. Specimens caught off the research vessel are placed in the cell and their swimming motion is analyzed with 3D kinematics, 3D flow visualization with a flow tomography system, and a lot of microscopy photography.

“We take that and we convert it into computer models, and use high-performance computing to run simulations and get a model of the flapping of the pteropod,” said Rajat Mittal, team member and professor of mechanical engineering at Johns Hopkins University who blogged the trip. “What we are hoping in the next few months is to take all this data that we have collected here in Palmer Station back with us and produce these simulations.”