New grant enables understanding of unstable glacier flow

by | posted in: Alaska, Field work, Research | 0

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.

Emma Swaninger defends M.S. thesis!

by | posted in: Greenland, Research, Teaching | 0

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 exhibit mysterious herd-like motion

by | posted in: Research | 0

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.

This work was published in May 2020 in the journal Polar Biology. A twitter thread about this work, with more photos, is here.

The moss ball colony we studied, where moss balls rolled around in herd-like fashion over the dirty ice surface.
Cross section of a typical Root Glacier moss ball

Chris Miele defends dissertation proposal, advances to Ph.D. candidate

by | posted in: Research, Teaching | 0

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.

UI grad students present at Northwest Glaciologists meeting

by | posted in: Greenland, Research | 0

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.

Lab group prepares for Northwest Glaciologists’ meeting

by | posted in: Uncategorized | 0

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.

Conference symposium highlights latest in Glacier Seismology

by | posted in: Research | 0

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.

Bartholomaus-mentored Ph.D. student wins Early Career Award for outstanding paper

by | posted in: Greenland, Publications, Research | 0

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.

Tristan Amaral defends M.S. thesis

by | posted in: Uncategorized | 0

UI Glacier Dynamics lab member Tristan Amaral recently gave an excellent summary of his master’s thesis research, “Validation of iceberg calving models on Greenland outlet glaciers.” During his presentation, Tristan discussed the challenges of identifying a universal calving law, appropriate for the diversity of tidewater glaciers in Greenland, his strategy for assessing these calving laws, and the relative accuracy and reliability of different calving laws.

Following his graduation, Tristan is working on completing the final revisions to his paper, to be submitted for peer review this summer at the Journal of Geophysical Research. In a month, he’ll be headed up to Alaska to work at Denali National Park for the summer, as an intern through the GSA Geoscientists in the Parks program.