David Ferris in Antarctica during one of his seven trips to obtain ice cores.
Actual Living Scientist: Dr. David Ferris, Research Scientist at Dartmouth College
Dr. David Ferris is a researcher who grew up in La Crosse, WI. He received his B.S. in Chemistry from the University of Wisconsin, La Crosse, and now works as a research scientist in the Earth Sciences department at Dartmouth. He has been working on the West Antarctic Ice Sheet (WAIS) Divide and the South Pole Ice (SPICE) Core projects, which require regular trips to Antarctica. We spoke with David to learn more about his work on these projects, and what it is like to live and work in Antarctica.
Climate change is a hot-button topic, no matter where you look. From the scientific community to politics and everyday life, topics like greenhouse gases and global warming are popping up more and more frequently – especially when we experience a balmy 70oF in Wisconsin during February. While Milwaukee certainly takes advantage of such pleasant surprises, it comes with a bit of skepticism. Ask any native, and they will quickly tell you not to get too used to things. Regardless of where you actually stand on climate change, most would agree that it is important to gain a better understanding of climate change, its causes, and its implications. That is exactly what Wisconsin scientist David Ferris aims to do, in his regular excursions to Antarctica.
David Ferris is one of the many researchers working to collect and analyze ice core samples from the South Pole. Summers in Antarctica where David works reach approximately -30oC (-22oF), which means the snow never melts. Rather, the snow builds up, and as the years pass, the snow is compressed into thick layers of ice. In each layer of ice, there are pockets of trapped air, which contain an undisturbed snapshot of the atmospheric conditions from its time in history. These samples are the real prize, and why teams of nearly three dozen scientists regularly volunteer to spend their winters and holiday season layered in parkas.
Scientists like David use these samples to measure levels of key chemical compounds in the preserved air and ice. These measurements inform us about what the planet was like before humans started recording this information; remarkably, some ice cores contain information that stretches back 68,000 years. The team likes to refer to their ice cores as “time capsules”, that can help them understand what Earth was like in the past.
However, obtaining these ice cores is not as easy as digging up a time capsule from your backyard. Each Antarctic summer (North American winter), a team of researchers packs their bags to spend three months drilling into the ice sheet. For the past five seasons, David has been working as an ice core driller with the South Pole Ice (SPICE) Core project team. In order to obtain the core samples without disrupting the air pockets, a specialized drill is used to cut through and bore down into the ice. Other scientists on the team, from UW-Madison, designed the drill for the SPICE Core Project. The entire process is time consuming and requires patience. David previously worked on the West Antarctic Ice Sheet Divide (WAIS Divide) Ice Core project, which obtained an ice core 3,405 meters (2.1 miles) long over the course of eight years. It is the longest US-drilled ice core to date. This sample was obtained in three meter pieces, each of which took approximately twenty minutes to extract. Each piece was then inspected for defects that could have allowed trapped air to escape. All cores are then packed, and transported by a long boat, plane, and truck ride to Colorado, where they are stored in freezers before being distributed to scientists for further testing. From start to finish, this entire process has to occur at temperatures below -20oC (-4oF) to ensure that the cores do not melt. This means that there is no heating system in the drilling and core storage areas.
The arch of the drill (left) and the drill itself (right) that David uses to bore down into the ice sheet to obtain cores for the SPICE Project.
Despite living in Wisconsin for many years, David expected it to be difficult to adapt to the Antarctic cold. He assumed he would literally freeze to death as soon as he stepped off the plane if he was not well prepared. To his pleasant surprise, this did not happen. In fact, adapting to the cold was easier than expected. David remembers waking up on his first few nights, drenched in sweat because he had bundled up too much for the night. He assumed the temperature would drop significantly at night. However, the sun never sets in Antarctica during the summer. Instead, it stays in the sky and circles around like a clock, which means the temperature and lighting does not change much between the day and night. The team was also happy to enjoy the beautiful landscapes around them, especially when the sky was full of halos and the snow formed diamond dust in the air.
WAIS Divide Project camp site.
At the end of each drilling season, David returns to New Hampshire, where he continues to analyze the ice cores at Dartmouth College. However, it is not time to hang up the parka just yet, as the ice cores need to stay frozen during analysis. First, the team must determine how old each layer of the ice core is. Each layer corresponds to a different year, so they can determine the age of the layer by counting the layers before it. This is similar to the way the age of a tree is determined by counting its rings. This particular sample, being 3405 meters long, gives information up to 68,000 years ago, with high resolution information up to 30,000 years ago. Given the most recent ice age was 40,000 years ago, the core gives critical information about the process from a glacial to inter-glacial period.
Ice core obtained from the SPICE Project before it is removed from the drill to be inspected. The blades of the drill can be seen around the edges of the bore.
Once the age of each layer is determined, the air and water conditions for each year are analyzed. Different scientists are interested in gaining different information. Some scientists are curious about the change in the levels of carbon dioxide concentrations in the atmosphere and water, while others want to determine the temperature of the planet each year. For analyzing samples of air, a sample of the core is placed into a vacuum chamber and crushed, releasing the air trapped inside of the ice. For analyzing samples of water, the ice is melted very slowly in a temperature controlled chamber to obtain the water sample. These air or water samples are then placed through different specialized pieces of equipment that are able to determine the concentration of different compounds. David is interested in determining sulfate concentrations in the ocean. By tracking spikes in sulfate, David’s research has helped create a prehistoric record of volcanic eruptions. This record helps climate modelers predict the effects of volcanic activity on our climate.
When the team combines all of their research, they have an outline of climate conditions over the past 30,000 years. Using this information, they are able to identify certain events, such as forest burnings, based on sudden changes in temperature and water composition. The ice cores also give information on wind patterns, ocean circulation, and ground conditions. All of this information helps them understand how the climate was affected by both gradual and abrupt events in the past. These ice cores provide a massive amount of data that is used to create models and simulations to predict how future climate changes will affect our planet.
The WAIS Divide and SPICE projects, from planning to drilling to analysis, take over ten years to complete, and both are still ongoing. David and his team members are very pleased with the progress so far, and are excited to continue analyzing their record-holding longest ice core. While the team enjoys their time in Antarctica, they are always excited to come back to warmer temperatures and start analysis. They believe that their work not only sheds light on future climate changes, but also impacts crop, water, and energy resource availability. Though, not all of the learnings from these endeavors are technical; David says he is continuously impressed with the ingenuity of the students he works with. The young scientists give him faith that if properly supported, future generations will be able to solve some of the biggest problems society will face in the near future. So, just like our native Wisconsinites warn, do not get too used to 70oF weather in February, because we have bright scientists uncovering information on climate change and taking care of our planet.
Written by Palak Pujara for the Milwaukee Area Science Advocates (MASA)
To learn more about the WAIS Divide Project, or SPICE Project, visit their websites:
WAIS Divide Project: http://www.waisdivide.unh.edu/
SPICE Project: http://spicecore.org/
References:
“Interview with David Ferris.” E-mail interview by author. March 05, 2017.
“Overview.” South Pole Ice Core. Accessed March 04, 2017. http://spicecore.org/about.shtml
“Overview.” WAIS Divide Ice Core. Accessed March 04, 2017. http://www.waisdivide.unh.edu/about/index.shtml