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Antarctica

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From left, graduate students Thomas Reilly and Hanxiao Wu with Weisen Shen. Wu and Shen are holding two of the 183 sensors they will place in the Antarctic. The team is shipping the sensors in the black container, which will travel through Port Hueneme, California and New Zealand before reaching the South Pole. Photo by Maeve McCarthy/ Angela Gruo

By Daniel Dunaief

While it’s easy to see and study materials in valleys or on the tops of bare mountains, it’s much more difficult to know what’s beneath 2.7 kilometers of ice. Turns out, that kind of question is much more than academic or hypothetical.

At the South Pole, glaciers sit on top of land that never sees the light of day, but that is relevant for the future of cities like Manhattan and Boston.

The solid land beneath glaciers has a strong effect on the movement of the ice sheet, which can impact the melting rate of the ice and sea level change.

Weisen Shen, Assistant Professor in the Department of Geosciences at Stony Brook University, recently received over $625,000 over the course of five years from the National Science Foundation to study the unexplored land beneath the East Antarctic Ice Sheet at the South Pole.

The subglacial water and hydrosystems, together with geology such as sediment or hard rocks, affect the dynamics and contribute to the movement speed of the ice sheet.

Once Shen provides a better understanding of the material beneath the ice, including glacial water, he can follow that up with other researchers to interpret the implications of ice sheet dynamics.

“We can predict better what’s the contribution of the Antarctic ice sheet to the sea level change” which will offer modelers a way to gauge the likely impact of global warming in future decades, he said.

Using seismic data

Starting this November, Shen and graduate students Siyuan Sui, Thomas Reilly and Hanxiao Wu will venture for two months to the South Pole with seismic monitors.

By placing 183 seismic nodes and installing an additional eight broad-band seismic stations, Shen and his team will quantify the seismic properties and, eventually, use them to infer the composition, density and temperature structure of the crust and the uppermost mantle.

The temperature when they place these monitors will be 10 to 30 degrees below 0 degrees Fahrenheit. They will need to do some digging as they deploy these sensors near the surface.

While the South Pole is believed to be geologically stable, signs of sub-glacial melting suggest the crust may bear a higher concentration of highly radioactive elements such as uranium, thorium and potassium.

Those natural elements “produce heat all the time,” said Shen. 

The process and analysis of seismic waves works in the same way it would for the study of a prism. Looking at the refraction of light that enters and leaves the prism from various angles can help researchers differentiate light with different frequencies, revealing clues about the structure and composition of the prism.

Earth materials, meanwhile will also cause a differentiation in the speed of surface waves according to their frequencies. The differentiation in speeds is called “dispersion,” which Shen and his team will use to quantify the seismic properties. The area has enough natural waves that Shen won’t need to generate any man-made energy waves.

“We are carefully monitoring how fast [the seismic energy] travels” to determine the temperature, density and rock type, Shen said.

The water beneath the glacier can act like a slip ’n slide, making it easier for the glacier to move.

Some large lakes in Antarctica, such as Lake Vostok, have been mapped. The depth and contours of sub glacier lakes near the South Pole, however, are still unclear.

“We have to utilize a lot of different methods to study that,” said Shen.

The Stony Brook researcher will collaborate with colleagues to combine his seismic results with other types of data, such as radar, to cross examine the sub ice structures.

The work will involve three years of gathering field data and two years of analysis.

Educational component

In addition to gathering and analyzing data, Shen has added a significant educational component to the study. For the first time, he is bringing along Brentwood High School science teacher Dr. Rebecca Grella, A PhD graduate from Stony Brook University’s Ecology and Evolutionary Biology program, Grella will provide lectures and classes remotely from the field.

In addition to bringing a high school teacher, Shen will fund graduate students at Stony Brook who can help Brentwood students prepare for the Earth Science regents exam.

Shen is working with Kamazima Lwiza, Associate Professor in the School of Marine and Atmospheric Sciences at Stony Brook, to bring Earth Science, including polar science, to schools in New York City and on Long Island with a bus equipped with mobile labs.

Lwiza, who is the Principal Investigator on the EarthBUS project, will work together with Shen to build a course module that includes a 45-minute lecture and exhibition.

Shen feels that the project will help him prepare to better educate students in graduate school, college, and K-12 in the community.

He feels a strong need to help K-12 students in particular with Earth Science.

As for students outside Brentwood, Shen said he has an open door policy in which the lab is receptive to high school and undergraduate students who would like to participate in his research all year long.

Once he collects the first batch of data from the upcoming trip to the South Pole, he will have to do considerable data processing, analysis and interpretation.

While Shen is looking forward to the upcoming field season, he knows he will miss time in his Stony Brook home with his wife Jiayi Xie, and his four-and-a-half year old son Luke and his 1.5 year old son Kai.

“It’s a huge burden for my wife,” Shen said, whose wife is working full time. When he returns, he “hopes to make it up to them.”

Shen believes, however, that the work he is doing is important in the bigger picture, including for his children.

Record high temperatures, which are occurring in the United States and elsewhere this summer, will “definitely have an impact on the dynamics of the ice sheet.” At the same time, the Antarctic ice sheet is at a record low.

“This is concerning and makes [it] more urgent to finish our work there,” he added.

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Heather Lynch at Spigot Peak in the Antarctic. Photo by Catherine Foley

By Daniel Dunaief

Counting penguins is like riding the highs and lows of Yankees rookie Aaron Judge’s home run streaks, followed by his series of strike outs. He’s not as bad as his strike outs suggest, although he’s also not a sure thing at the plate either.

Similarly, in local populations, the Adélie penguin, which waddles to and fro squawking on land and gliding gracefully through the water, isn’t as clear a barometer of changes in the environment. Also, like Judge, when populations rise and fall, people are eager to offer their explanations for exactly what’s happening, even if the sensational explanations — he’s not that good, no, wait, he’s the greatest ever — may overstate the reality.

Heather Lynch visits Cape Lookout in Antarctica during recent trip that included an NBC TV crew that produced a feature for ‘Sunday Night with Megan Kelly.’ Photo by Jeff Topham

“We have to be careful not to be overreactive,” said Heather Lynch, an associate professor of ecology and evolution at Stony Brook University. “The concern is that, when we see increases or decreases, the implication is that there’s a miraculous recovery or a catastrophic crash.”

That, however, is inconsistent with Lynch’s recent results, which were published in the journal Nature Communications. Examining penguin data from 1982 to 2015, Lynch, Christian Che-Castaldo, who is a postdoctoral researcher in Lynch’s lab, and nine other researchers looked to see if there’s a way to connect the size of the population to changes in the environment. The study involved two teams of researchers, one supported by NASA and the other backed by the National Science Foundation.

“It’s a noisy system,” Lynch concluded. Managers of the populations of krill, small crustaceans that are the mainstay of the Adélie diet, try to use time series of key indicator species to understand what’s going on in the marine realm. In this article, Lynch said, local Adélie penguin populations may not be a clear signal of the health of the krill stocks because penguin abundance fluctuates for reasons she and her team couldn’t pinpoint.

These penguins, which Lynch has counted during her field work in the Antarctic, exhibit changes in population that can run contrary to the health, or stressed condition, of the environment.

“You can’t have your finger on the pulse” with the available data, Lynch said. “Part of our inability to model year-to-year changes is because we can’t measure the right things in the environment.”

The drivers of abundance fluctuations likely involve other animals or aspects of the krill fisheries they couldn’t model, she suggested.

“There’s a lot we don’t know about what penguins do under water, where they spend a large portion of their time and where they feed,” Grant Humphries, who was in Lynch’s lab for a year and now runs his own data science company in Scotland called Black Bawks Data Science Ltd, explained in an email. “The signals that drive year to year changes might actually lie there.”

Tom Hart, a researcher of the Department of Zoology at the University of Oxford who was not involved in this study, explores local scale variation in penguin populations. Locally, Hart said in an interview by Skype, “Things are incredibly noisy. When you aggregate, you get good signals, but with some error.” He suggested that this research drives him on further, showing that “local influences are important” because there’s so much variance left to explain. Lynch’s research is “a really good study and shows very well what’s happening on the regional scale, but leaves open what happens below that,” he said.

Indeed, Lynch suggested that by putting sites together, researchers can look at larger areas, which provide a clearer picture on shorter time scales.

Michael Polito, an assistant professor in the Department of Oceanography and Coastal Sciences at Louisiana State University who was not involved in the study, suggests that this extensive analysis indicates that “you can still look at the relationship between the abundance of penguins and the environment in a robust way. Even though any individual time series may not be the best way to understand these relationships, in the aggregate you can use them.”

Managers who set fishery policies in Antarctic waterways are often concerned about harvesting too much krill, leaving the penguins without enough food to survive and feed their chicks.

The challenge with this result, Lynch acknowledges, is that it makes setting krill boundaries more difficult.

A strategy that involves resetting conservation targets based on annual monitoring appears unrealistic given these results, Lynch said. “From a practical standpoint, we threw in everything we could and could explain only a tiny fraction of the variation,” she said.

Hart added that this is “not an argument to fish away,” he said. “We need to understand what’s going on at a local scale and we’re not there yet.”

To get people involved, Lynch and her team created a science competition, called Random Walk of the Penguins, to see who could predict the overall penguin populations for Adélie, gentoo and chinstrap penguins from the 2014 to 2017 seasons.

The competition, which was a collaborative effort with Oceanites, Black Bawks Data Science and Driven Data included $16,000 in prize money, which was donated by NASA. Entrants could use data from the 1982 through the 2013 seasons. The contest drew competitors from six continents. Of the five winners, all were from different countries.

Humphries, who was the lead on the data science computation, said the results were “somewhat humbling” because competitors were able to make “decent predictions” using only the time series. “With long-term predictions and for determining the tipping points, there is still a lot of work to be done.”

Lynch is relieved that her co-authors supported the direction the article took. “I’m a skeptic by nature and more than happy to throw orthodoxy (or even my own previous work) under the bus,” she wrote in an email. “I do hope that others will use our model as a starting point and we’ll never go back to the old days where everyone looked only at ‘their sites.’”

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