It’s 3:15 p.m. and the sun is setting at Anvers Island. Just off the Antarctic Peninsula, surrounded by 300-foot cliffs of ice, Jeannette Yen pauses outside Palmer Station to watch. The sun spills over the ice cliffs. The frozen landscape melts in a golden glow.
This is one of nature’s great laboratories. Yen and her team of scientists are conducting experiments here that are possible nowhere else. Outfitted in red parkas, they are not here to drill into frozen lakes or fly over thinning ice sheets. They spend what little daylight they have searching for tiny organisms in the frigid waters.
The scientists climb aboard the R/V Lawrence M Gould, a massive research vessel operated by the National Science Foundation (NSF). They cruise past giant icebergs and through rafts of loose ice to Palmer Deep, a location where the water is 2,000 feet (600 meters) deep. From the huge stern A-frame of the ship, they lower plankton nets into the zero-degree Celsius water and haul live animals aboard. In Antarctica, zero degrees Celsius is a pleasant day, but the recent bout of 80-knot wind gusts tells them the austral winter is on its way.
“The weather has been good,” Yen said. “We’ve gone out and have been collecting plankton all around.”
Skype session between Georgia Tech Research News in Atlanta and Georgia Tech "Team Pteropod" at Palmer Station, Antarctica.
Yen, a professor of biology at the Georgia Institute of Technology in Atlanta, is on her second polar plunge. She’s an ecologist with an engineer’s eye. Her team of biologists and engineers haul each day’s catch back to the lab at Palmer Station, which provides no escape from the cold. There, the scientists study plankton swimming motion with video cameras in a room kept at zero degrees Celsius, to mimic the animals’ natural environment.
Plankton are the base of the food chain, but their environment is changing. Around the southern continent, the water temperature is stable at around zero degrees Celsius because of the Antarctic Circumpolar Current. Carbon dioxide, a potent greenhouse gas, easily dissolves in the cold water, acidifying the ocean. The acidifying oceans might be triggering a destructive chain of events underwater that could harm the food web around the world.
That’s why Yen and her team have come here, in search of a tiny organism that could be a canary in the coal mine of climate change.
From left to right, Rebecca Wolf, Deepak Adhikari, Jeannette Yen, and Rajat Mittal in Antarctica. Credit: Jeannette Yen
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.
Palmer Station, Antarctica.
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.”
Jeannette Yen and Deepak Adhikari inside their lab at Palmer Station. Credit: Rajat Mittal.
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.
Yen, Wolf, and Adhikari with their tomography system. Aquatic organisms are placed in the clear receptacle, and their movements are captured with cameras. Credit: Rajat Mittal.
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.”
A massive iceberg, as seen from a glacier in Antarctica. Credit: Rajat Mittal.