Glacier moss balls, and the mystery behind their motion, gained international attention this summer, following a publication in Polar Biology. Group leader Tim Bartholomaus appeared on NPR’s popular Morning Edition broadcast, the CBC’s As It Happens radio show, podcasts, magazines, and many web sites.
See the Media Coverage page for a listing of some of the highlights. It’s been a delight to engage on this topic!
Prof. Tim Bartholomaus and partners have received a $1.2M grant from the U.S. National Science Foundation to understand the connections between glacier sliding and the water and sediment underneath glaciers and ice sheets. This relationship between glacier flow, water, and sediment is poorly known and glaciologists are not yet confident whether increasing melt of the Greenland Ice Sheet and global glaciers is likely to speed up ice flow, and therefore further increase sea level, or slow down ice flow and potentially diminish the rate at which sea levels will rise.
The terminus of Turner Glacier, photographed shortly after its last surge in May 2013, where it calves icebergs into Disenchantment Bay.
To address this question, Dr. Bartholomaus, his graduate students, and collaborators from Boise State University, will be traveling to a remote, mountainous region of Alaska over four years, to study a peculiar glacier that undergoes ten-fold increases in flow speed, every 6 or so years. These unusual “glacier surges” are known to depend on subglacial water and mud at the bottom of glaciers, but hypotheses regarding their development have not been tested. By deploying seismometers, GPS receivers, radar, and other equipment, to the glacier surface, and then using computer simulations to analyze the results, Dr. Bartholomaus and his teammates will produce better understanding of the physics of glacier flow, and ultimately enable better predictions of coming sea level rise.
This project begins this month, August 2020, when the team flies to Yakutat, Alaska, and then via helicopter out to Turner Glacier, in the Saint Elias Mountains.
The UI Glacier Dynamics lab will be recruiting a new Ph.D. student to begin work on this project, starting in the fall of 2021.
Master of Science candidate Emma Swaninger did a phenomenal job presenting and defending the results of her last two years of research. Among other findings, Emma demonstrated that near-terminus ice is likely weaker than typically expected, and that even thin, brief, mid-summer, ice melange can provide rigid support to a glacier terminus. Her presentation online was well-attended by colleagues, friends and family.
Congratulations, Emma, on a job well done! I was proud to be your advisor and am excited that you’ll be continuing your work at the University of Idaho by coordinating our introductory labs.
Glacier moss balls are globular, ~10 cm masses of moss, with small amounts of sediment found on some glaciers. These enigmatic, rare components of glacier biology have seen some study at select glaciers around the world, but their longevity on glaciers and patterns of motion have been entirely unknown until now.
Glacier moss balls on the Root Glacier, Alaska
Starting in 2009, before I’d begun my Ph.D. program, now-UIdaho professor of wildlife biology, Sophie Gilbert, and I studied an unusually dense concentration of glacier moss balls on the Root Glacier, in Wrangell-St. Elias National Park and Preserve, Alaska. We tagged individual glacier moss balls with unique colored glass beads to identify them, then revisited the colony every 5-7 days to study their motion. We also returned in subsequent years to re-identify individuals. Dr. Gilbert and I later teamed up with Dr. Scott Hotaling to publish this work.
We found that moss balls exhibited consistent, herd-like motion, changing both their speeds and travel directions together. Moss balls moved on average 2.5 cm per day, at rates somewhat controlled by the amount of glacier surface ablation. Early during our 1.5 month study period in 2009, moss balls rolled predominantly towards the south, but later moved towards the west. We weren’t able to explain this migratory, herd-like motion by considering the downhill, wind, or solar radiation directions. Thus, the changing directions of their motion remains a mystery. By revisiting our site in the three subsequent years, we were able to find that moss ball growth is relatively slow and that individual moss balls can persist on the glacier for many years- at least six but potentially much longer.
Ph.D. student Chris Miele, in the UI Glacier Dynamics lab, successfully defended his dissertation proposal today. His dissertation, titled “Transition zones in floating glacier ice in Greenland,” is focused around better understanding the dynamics and iceberg calving of marine terminating glaciers. To an audience of over 35 Zoom attendees, Chris did a great job presenting his work with both physical rigor and engaging humor. Chris subsequently passed his comprehensive exam, and advanced to Ph.D. candidacy.
Great work, Chris! Congratulations!
Thanks are also due to Chris’ advisory committee members, Dr. Ellyn Enderlin, Dr. Eric Mittelstaedt, and Dr. Gabriel Potirniche.
Three UI students, Chris Miele, Emma Swaninger, and Abby Lute, attended the 2019 Northwest Glaciologists meeting in Corvallis, Oregon, last week. Chris and Emma are students in the Glacier Dynamics lab and shared their work focused on understanding dynamic changes around iceberg calving, whereas Abby is a collaborating student in the lab, advised by John Abatzoglou in the Geography Department. Chris, Emma, and Abby did great jobs communicating their work and fielded questions from an engaged audience. As a whole, the lab had a great time sharing science and connecting with friends old and new.
In the attached pictures, Chris and Emma present their research.
Members of the Glacier Dynamics lab at UIdaho are preparing this week for next week’s gathering of Northwest Glaciologists. Chris Miele will present a theory-based analysis on the interplay between submarine melt and iceberg calving, and how calving varies with the spatial pattern of submarine melt. Emma Swaninger will present on the response of Rink Glacier to the brief formation of ice melange within its West Greenland fjord. And Abby Lute, a Ph.D. student on whose committee Tim serves, will present her work on the climatic and other environmental factors controlling the distribution of rock glaciers.
It’s an exciting time as we hustle to prepare results, and we’re looking forward to meeting next week with friends and colleagues in Corvallis, Oregon.
The group members for the Glacier Dynamics Lab at the University of Idaho have been updated! Check out the Lab Group page to learn more about our current members: Emma and Chris, along with Tim.
At the International Union of Geodesy and Geophysics meeting in Montreal, Canada, Bartholomaus co-convened and presented during a symposium on Glacier Seismology. The well-attended symposium featured talks from authors around the world on topics as diverse as ice shelves, basal sliding, and avalanches. Bartholomaus presented his most recent work on the use of seismology to reveal the workings of the subglacial hydrologic system of Lemon Creek Glacier, Alaska.
Denis Felikson has been awarded the 2019 Early Career Award by the International Association of Cryospheric Sciences. Tim Bartholomaus had the privilege of working with Denis while the two of them were at the University of Texas in Austin, and worked with Ginny Catania. During that time, Denis published a paper with Bartholomaus that demonstrated how glacier geometry in Greenland controls the spatial pattern of ice loss from the ice sheet. Denis is now a postdoc at the NASA Goddard Space Flight Center. Congratulations, Denis! The citation is found here.