Courtesy of the National Science Foundation Using a specially designed hot-water drill to cleanly bore…
NIU scientist Ross Powell is leading a National Science Foundation-supported effort to drill through the ice, probe grounding zone’s influence on rising sea levels
Never probed its dark shores. Never documented what life exists there under the ice. Never taken measurements to assess the coastline stability.
The problem: This grounding zone is buried by ice thicker than the Empire State Building is tall. Beyond its shoreline, the ice extends out over the sea in a floating slab known as the Ross Ice Shelf, which covers a region nearly the size of Spain.
Exploring the unknown
At a site in the Antarctic wilderness on the inner edge of the Ross Ice Shelf, the team will use a hot water drill to bore a 1-foot diameter hole through the ice in January. The scientists will lower cameras and a suite of slimly designed high-tech instruments through about a half mile of ice into a cavity of shallow seawater – allowing them to peer into an aquatic world never before seen and analyze its iced-over coastline.
For Powell and others on the project – including three students from NIU and geologist Reed Scherer, who is among the lead scientists – the expedition is akin to traveling to another planet.
“It’s like exploring in outer space,” Powell says. “Unless you go there, you can’t absolutely confirm what is going on.
“While remote sensing has given us a sense of the grounding-zone environment, the images, data and samples we retrieve will provide us with a wealth of new information,” he adds.
The new data will supply scientific modelers with important information needed to predict the potential speed of ice sheet demise and the impact of climate change on the world’s oceans and coastal communities.
How stable is the ice sheet?
More specifically, the work will help scientists assess the stability of the West Antarctic Ice Sheet, most of which sits below sea level. (Ice sheets are on land; ice shelves over water.) It is the last ice sheet on Earth resting in a deep marine basin and is the most likely player in any future, rapid sea-level rise. If the grounding zone is retreating or primed to retreat, rapid changes in ice behavior could follow over the next century.
“Scientists worldwide are working to determine the risk of West Antarctic Ice Sheet collapse, but we don’t have enough information,” Scherer says. “This work will provide missing pieces to the puzzle and give us an idea of how quickly things are happening.
“Coastlines are dynamic places – and the Antarctic is no exception,” he adds. “As land transitions to sea, low-lying muddy flats along the coastline are thought to ‘grease the skids’ of the ice sheet as it feeds into ocean.”
The WISSARD team in 2013 successfully explored subglacial Lake Whillans, a body of water trapped beneath the ice sheet, and reported in Nature this past August on its find of abundant and viable microbial life.
Previous research had determined Lake Whillans fills with water and drains every five years or so into a stream or streams beneath the ice sheet and running to the ocean. The grounding zone targeted for investigation is about 70 miles northwest and downstream of the lake, and scientists expect to find a discharge of freshwater and sediment from the lake and areas upstream.
“Under conditions of global warming, the grounding line becomes more important in terms of ice sheet stability and migration,” Powell says. “If the region beneath the ice and on land is extensively wet and muddy, it could allow the ice to flow more quickly into the ocean and potentially make the ice more unstable to raise world sea level more rapidly than at present. There are also tides in this area, as with any coastline, and the ice moves up and down. We don’t know what effect this movement has on the discharge of water and sediment from land into sea.
“Our team also wants to learn what life forms exist in this area of the sea beneath the ice,” Powell says. “It will be interesting to find out if the microbial life is similar or different to what was found in the lake, and we’re unsure if we’ll see larger life forms, such as fish or crabs. It seems unlikely, but who knows.”
Scientists and students from about a dozen universities are involved in the research effort – with NIU, Montana State University and the University of California Santa Cruz serving as lead institutions. Powell is the project’s chief scientist.
Project that nearly wasn’t
Despite the importance of the grounding-zone examination, the latest effort almost didn’t happen.
Originally, the downstream drilling was to have taken place early this year. Preparations were well under way when they were scuttled by the partial U.S. government shutdown. It was eventually resolved, but because Antarctic operations are logistically complex, there wasn’t enough time and resources left to prepare for field deployment.
“We at NSF are very excited that the WISSARD project will be able to complete its work this year,” says Lisa Clough, an NSF program officer for Antarctic science.
“The work done by the WISSARD team within subglacial Lake Whillans has confirmed the long-hypothesized existence of dynamic life beneath the ice sheet, and completing the work at the Whillans grounding zone is essential to move forward the scientific understanding of the integrated subglacial hydrological system,” Clough adds. “WISSARD scientists have shown there is not just land and water beneath the ice, but most likely an entire coastal wetlands system, and the team’s direct access of the grounding zone region will be critical in our understanding of the flow of water, ice, particles and life across this transition zone.”
The ‘deep field’
The project requires extensive logistical support.
Two years ago, an operations team, using giant Caterpillar and Challenger tractors, pulled sleds about 600 miles across the Ross Ice Shelf, before setting up camp at the Lake Whillans drill site.
When scientific work was completed, some of the larger equipment was packed up and left at the site for the coming project. That included the $3 million hot-water drill and large shipping containers that serve as equipment and command centers.
Now buried by snow from two Antarctic winters, that equipment will be dug out and transported to the grounding zone. Fuel, supplies and other equipment will again be transported across the ice on sleds, while weather-sensitive instruments will be flown in, including several types of water sensors and samplers, three types of sediment corers, a geothermal probe and a small remotely operated vehicle equipped with cameras for underwater exploration.
Scientists and students, who will arrive at the drill site via airplane, will have several days to a week to complete their fieldwork. Since January falls during the Antarctic summer, the sun will never set – and the work will never stop.
“Once the borehole is made, it’s a 24-hour science operation,” Scherer says. “Last time, we had four days of science, which meant four days of very little sleep.”
Still, it’s the opportunity of a lifetime for NIU students Tim Hodson, who’s working on his Ph.D. and making his second trip to Antarctica, and geology graduate students Jason Coenen and Rebecca Puttkammer, making their first trip.
“I cannot get over the uniqueness and the awesomeness of this opportunity,” said the 25-year-old Puttkammer, a first-year graduate student who came to NIU from Northwestern University to study with Powell and Scherer. “This is my research dream, and it’s hard to believe I’m achieving it during my master’s program.
“I think I’ll miss the sunset and sunrise,” she adds. “But it will be worth it.”
More information on NIU's role in the WISSARD project is available here.