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Lawrence JD, Washam PM, Stevens C, Hulbe C, Horgan HJ, Dunbar G, Calkin T, Stewart C, Robinson N, Mullen AD, Meister MR, Hurwitz BC, Quartini E, Dichek DJG, Spears A, Schmidt BE. Crevasse refreezing and signatures of retreat observed at Kamb Ice Stream grounding zone. NATURE GEOSCIENCE 2023; 16:238-243. [PMID: 36920161 PMCID: PMC10005960 DOI: 10.1038/s41561-023-01129-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 01/16/2023] [Indexed: 06/18/2023]
Abstract
Ice streams flowing into Ross Ice Shelf are presently responsible for around 10% of the mass flux from West Antarctica, with the noteworthy exception of Kamb Ice Stream, which stagnated in the late 1800s. The subsequent reduction in ice supply led to grounding-line retreat at the coastal margin where Kamb transitions into the floating Ross Ice Shelf. Grounding-line migration is linked to broader changes in ice-sheet mass balance and sea level, but our understanding of related ice, ocean and seafloor interactions is limited by the difficulty in accessing these remote regions. Here we report in situ observations from an underwater vehicle deployed at Kamb that show how fine-scale variability in ice and ocean structure combine to influence a diversity of ice-ocean interactions. We found a stratified water column within a tenth of a degree of freezing at the ice base and mapped basal crevasses with supercooled water and active marine ice formation. At the seafloor, we interpret parallel ridges as crevasse impressions left as the ice lifted off during grounding-line retreat. These observations from a recently ungrounded sub-shelf environment illuminate both the geomorphological signatures of past grounding-line retreat and the fine-scale sensitivity of ongoing ice-ocean interactions to ice topography.
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Affiliation(s)
- J. D. Lawrence
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Honeybee Robotics, Exploration Systems, Altadena, CA USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - P. M. Washam
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - C. Stevens
- Ocean Dynamics Group, National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand
- Department of Physics, University of Auckland, Auckland, New Zealand
| | - C. Hulbe
- School of Surveying, University of Otago, Dunedin, New Zealand
| | - H. J. Horgan
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - G. Dunbar
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - T. Calkin
- Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
| | - C. Stewart
- Ocean Dynamics Group, National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand
| | - N. Robinson
- Ocean Dynamics Group, National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand
| | - A. D. Mullen
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - M. R. Meister
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - B. C. Hurwitz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
| | - E. Quartini
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - D. J. G. Dichek
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
| | - A. Spears
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA USA
| | - B. E. Schmidt
- Department of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY USA
- Department of Astronomy, Cornell University, Ithaca, NY USA
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Mantelli E, Haseloff M, Schoof C. Ice sheet flow with thermally activated sliding. Part 1: the role of advection. Proc Math Phys Eng Sci 2019; 475:20190410. [PMID: 31736651 DOI: 10.1098/rspa.2019.0410] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 09/24/2019] [Indexed: 11/12/2022] Open
Abstract
Flow organization into systems of fast-moving ice streams is a well-known feature of ice sheets. Fast motion is frequently the result of sliding at the base of the ice sheet. Here, we consider how this basal sliding is first initiated as the result of changes in bed temperature. We show that an abrupt sliding onset at the melting point, with no sliding possible below that temperature, leads to rapid drawdown of cold ice and refreezing as the result of the increased temperature gradient within the ice, and demonstrate that this result holds regardless of the mechanical model used to describe the flow of ice. Using this as a motivation, we then consider the possibility of a region of 'subtemperate sliding' in which sliding at reduced velocities occurs in a narrow range of temperatures just below the melting point. We confirm that this prevents the rapid drawdown of ice and refreezing of the bed, and construct a simple numerical method for computing steady-state ice sheet profiles that include a subtemperate region. The stability of such an ice sheet is analysed in a companion paper.
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Affiliation(s)
- E Mantelli
- Geophysics Department, Stanford University, Stanford, CA, USA.,Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - M Haseloff
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - C Schoof
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
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Abstract
Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution.
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Mikucki JA, Lee PA, Ghosh D, Purcell AM, Mitchell AC, Mankoff KD, Fisher AT, Tulaczyk S, Carter S, Siegfried MR, Fricker HA, Hodson T, Coenen J, Powell R, Scherer R, Vick-Majors T, Achberger AA, Christner BC, Tranter M. Subglacial Lake Whillans microbial biogeochemistry: a synthesis of current knowledge. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:rsta.2014.0290. [PMID: 26667908 DOI: 10.1098/rsta.2014.0290] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Liquid water occurs below glaciers and ice sheets globally, enabling the existence of an array of aquatic microbial ecosystems. In Antarctica, large subglacial lakes are present beneath hundreds to thousands of metres of ice, and scientific interest in exploring these environments has escalated over the past decade. After years of planning, the first team of scientists and engineers cleanly accessed and retrieved pristine samples from a West Antarctic subglacial lake ecosystem in January 2013. This paper reviews the findings to date on Subglacial Lake Whillans and presents new supporting data on the carbon and energy metabolism of resident microbes. The analysis of water and sediments from the lake revealed a diverse microbial community composed of bacteria and archaea that are close relatives of species known to use reduced N, S or Fe and CH4 as energy sources. The water chemistry of Subglacial Lake Whillans was dominated by weathering products from silicate minerals with a minor influence from seawater. Contributions to water chemistry from microbial sulfide oxidation and carbonation reactions were supported by genomic data. Collectively, these results provide unequivocal evidence that subglacial environments in this region of West Antarctica host active microbial ecosystems that participate in subglacial biogeochemical cycling.
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Affiliation(s)
- J A Mikucki
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA Department of Biology, Middlebury College, Middlebury, VT 05753, USA
| | - P A Lee
- Hollings Marine Lab, College of Charleston, Charleston, SC 29412, USA
| | - D Ghosh
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
| | - A M Purcell
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
| | - A C Mitchell
- Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, UK
| | - K D Mankoff
- Department of Geosciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - A T Fisher
- Earth and Planetary Sciences, University of California, Santa Cruz, CA, USA
| | - S Tulaczyk
- Earth and Planetary Sciences, University of California, Santa Cruz, CA, USA
| | - S Carter
- Institute for Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, CA 92093, USA
| | - M R Siegfried
- Institute for Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, CA 92093, USA
| | - H A Fricker
- Institute for Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, CA 92093, USA
| | - T Hodson
- Department of Geology and Environmental Geosciences Northern, Illinois University, DeKalb, IL 60115, USA
| | - J Coenen
- Department of Geology and Environmental Geosciences Northern, Illinois University, DeKalb, IL 60115, USA
| | - R Powell
- Department of Geology and Environmental Geosciences Northern, Illinois University, DeKalb, IL 60115, USA
| | - R Scherer
- Department of Geology and Environmental Geosciences Northern, Illinois University, DeKalb, IL 60115, USA
| | - T Vick-Majors
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA
| | - A A Achberger
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - B C Christner
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - M Tranter
- Bristol Glaciology Centre, Geographical Sciences, University of Bristol, Bristol BS8 1SS, UK
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Rack FR. Enabling clean access into Subglacial Lake Whillans: development and use of the WISSARD hot water drill system. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:rsta.2014.0305. [PMID: 26667915 DOI: 10.1098/rsta.2014.0305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/08/2015] [Indexed: 06/05/2023]
Abstract
Clean hot water drill systems (CHWDSs) are used with clean access protocols for the exploration of subglacial lakes and other subglacial aquatic environments (e.g. ice-shelf cavities) in Antarctica. A CHWDS developed for the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project by the Science Management Office at the University of Nebraska-Lincoln (UNL-SMO), USA, was specifically designed for use in West Antarctica, where the US Antarctic Program's South Pole Traverse could assist with logistical support. The initial goal was to provide clean access holes through ice up to 1000 m thick following environmental stewardship guidelines; however, the existing design allows this CHWDS to be used for ice thicknesses up to 2000 m following modifications to accommodate longer hose lengths. In January 2013, the WISSARD CHWDS successfully provided for the first time a clean access borehole through 800 m of ice into Subglacial Lake Whillans beneath the West Antarctic Ice Sheet for the deployment of scientific instruments and sampling tools. The development and initial use of the WISSARD CHWDS required the project team to address a number of constraints while providing contingencies to meet the defined project scope, schedule and budget.
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Affiliation(s)
- Frank R Rack
- ANDRILL Science Management Office, University of Nebraska-Lincoln, 126 Bessey Hall, Lincoln, NE 68588-0341, USA
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Hall BL, Denton GH, Stone JO, Conway H. History of the grounded ice sheet in the Ross Sea sector of Antarctica during the Last Glacial Maximum and the last termination. ACTA ACUST UNITED AC 2013. [DOI: 10.1144/sp381.5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractKnowledge of variations in the extent and thickness of the Antarctic Ice Sheet is key for understanding the behaviour of Southern Hemisphere glaciers during the last ice age and for addressing issues involving global sea level, ocean circulation and climate change. Insight into past ice-sheet behaviour also will aid predictions of future ice-sheet stability. Here, we review terrestrial evidence for changes in ice geometry that occurred in the Ross Sea sector of Antarctica at the Last Glacial Maximum (LGM) and during subsequent deglaciation. During the LGM, a thick grounded ice sheet extended close to the continental shelf edge in the Ross Embayment. This ice reached surface elevations of more than 1000 m along the coast of the central and southern Transantarctic Mountains and Marie Byrd Land. The local LGM occurred by 18 ka on the coast, but as late as 7–10 ka inland. The first significant thinning took place at roughly 13 ka, with most ice loss happening in the Holocene. This history makes it unlikely that the Ross Sea sector was a major contributor to meltwater pulse 1A (MWP 1A). Resolution of a possible Antarctic origin for MWP 1A awaits detailed reconstructions from all sectors of the ice sheet.
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Affiliation(s)
- Brenda L. Hall
- Climate Change Institute, University of Maine, Orono, ME, USA
- School of Earth and Climate Sciences, University of Maine, Orono, ME, USA
| | - George H. Denton
- Climate Change Institute, University of Maine, Orono, ME, USA
- School of Earth and Climate Sciences, University of Maine, Orono, ME, USA
| | - John O. Stone
- Department of Earth and Space Sciences, University of Washington, Seattle, WA, USA
| | - Howard Conway
- Department of Earth and Space Sciences, University of Washington, Seattle, WA, USA
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Bougamont M, Price S, Christoffersen P, Payne AJ. Dynamic patterns of ice stream flow in a 3-D higher-order ice sheet model with plastic bed and simplified hydrology. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jf002025] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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8
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Siple Coast subglacial aquatic environments: The Whillans Ice Stream Subglacial Access Research Drilling Project. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010gm000932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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9
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Christoffersen P, Tulaczyk S, Behar A. Basal ice sequences in Antarctic ice stream: Exposure of past hydrologic conditions and a principal mode of sediment transfer. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jf001430] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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Pollard D, DeConto RM. Modelling West Antarctic ice sheet growth and collapse through the past five million years. Nature 2009; 458:329-32. [DOI: 10.1038/nature07809] [Citation(s) in RCA: 747] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Accepted: 01/08/2009] [Indexed: 11/09/2022]
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