scholarly journals Physiological Ecology of Microorganisms in Subglacial Lake Whillans

2016 ◽  
Vol 7 ◽  
Author(s):  
Trista J. Vick-Majors ◽  
Andrew C. Mitchell ◽  
Amanda M. Achberger ◽  
Brent C. Christner ◽  
John E. Dore ◽  
...  
Keyword(s):  
Physiological Ecology ◽  
Subglacial Lake ◽  
Subglacial Lake Whillans

Subglacial Lake Whillans — Ice-penetrating radar and GPS observations of a shallow active reservoir beneath a West Antarctic ice stream

2012 ◽  
Vol 331-332 ◽  
pp. 237-245 ◽  
Author(s):  
Knut Christianson ◽  
Robert W. Jacobel ◽  
Huw J. Horgan ◽  
Sridhar Anandakrishnan ◽  
Richard B. Alley
Keyword(s):  
Subglacial Lake ◽  
West Antarctic ◽  
Ice Stream ◽  
Subglacial Lake Whillans ◽  
Gps Observations

scholarly journals WISSARD at Subglacial Lake Whillans, West Antarctica: scientific operations and initial observations

2014 ◽  
Vol 55 (65) ◽  
pp. 51-58 ◽  
Author(s):  
Slawek Tulaczyk ◽  
Jill A. Mikucki ◽  
Matthew R. Siegfried ◽  
John C. Priscu ◽  
C. Grace Barcheck ◽  
...  
Keyword(s):  
Sea Water ◽  
Freezing Point ◽  
Water Pressure ◽  
Sediment Cores ◽  
Water Reservoir ◽  
Hot Water ◽  
Subglacial Lake ◽  
Lake Bottom ◽  
Filtration Unit ◽  
Subglacial Lake Whillans

AbstractA clean hot-water drill was used to gain access to Subglacial Lake Whillans (SLW) in late January 2013 as part of the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project. Over 3 days, we deployed an array of scientific tools through the SLW borehole: a downhole camera, a conductivity–temperature–depth (CTD) probe, a Niskin water sampler, an in situ filtration unit, three different sediment corers, a geothermal probe and a geophysical sensor string. Our observations confirm the existence of a subglacial water reservoir whose presence was previously inferred from satellite altimetry and surface geophysics. Subglacial water is about two orders of magnitude less saline than sea water (0.37–0.41 psu vs 35 psu) and two orders of magnitude more saline than pure drill meltwater (<0.002 psu). It reaches a minimum temperature of –0.55~C, consistent with depression of the freezing point by 7.019 MPa of water pressure. Subglacial water was turbid and remained turbid following filtration through 0.45 µm filters. The recovered sediment cores, which sampled down to 0.8 m below the lake bottom, contained a macroscopically structureless diamicton with shear strength between 2 and 6 kPa. Our main operational recommendation for future subglacial access through water-filled boreholes is to supply enough heat to the top of the borehole to keep it from freezing.

scholarly journals Solute sources and geochemical processes in Subglacial Lake Whillans, West Antarctica

Geology ◽  
2016 ◽  
Vol 44 (5) ◽  
pp. 347-350 ◽  
Author(s):  
Alexander B. Michaud ◽  
Mark L. Skidmore ◽  
Andrew C. Mitchell ◽  
Trista J. Vick-Majors ◽  
Carlo Barbante ◽  
...  
Keyword(s):  
Geochemical Processes ◽  
West Antarctica ◽  
Subglacial Lake ◽  
Subglacial Lake Whillans

scholarly journals Enabling clean access into Subglacial Lake Whillans: development and use of the WISSARD hot water drill system

2016 ◽  
Vol 374 (2059) ◽  
pp. 20140305 ◽  
Author(s):  
Frank R. Rack
Keyword(s):  
Hot Water ◽  
Ice Shelf ◽  
West Antarctic Ice Sheet ◽  
Subglacial Lake ◽  
West Antarctic ◽  
Science Management ◽  
University Of Nebraska Lincoln ◽  
Subglacial Lakes ◽  
The University ◽  
Subglacial Lake Whillans

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.

scholarly journals Microbial Community Structure of Subglacial Lake Whillans, West Antarctica

2016 ◽  
Vol 7 ◽  
Author(s):  
Amanda M. Achberger ◽  
Brent C. Christner ◽  
Alexander B. Michaud ◽  
John C. Priscu ◽  
Mark L. Skidmore ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
West Antarctica ◽  
Subglacial Lake ◽  
Subglacial Lake Whillans

scholarly journals Subglacial Lake Whillans microbial biogeochemistry: a synthesis of current knowledge

2016 ◽  
Vol 374 (2059) ◽  
pp. 20140290 ◽  
Author(s):  
J. A. Mikucki ◽  
P. A. Lee ◽  
D. Ghosh ◽  
A. M. Purcell ◽  
A. C. Mitchell ◽  
...  
Keyword(s):  
Water Chemistry ◽  
Current Knowledge ◽  
Sulfide Oxidation ◽  
Lake Ecosystem ◽  
Subglacial Lake ◽  
West Antarctic ◽  
Microbial Ecosystems ◽  
Subglacial Lakes ◽  
Close Relatives ◽  
Subglacial Lake Whillans

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 CH 4 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.

scholarly journals High geothermal heat flux measured below the West Antarctic Ice Sheet

2015 ◽  
Vol 1 (6) ◽  
pp. e1500093 ◽  
Author(s):  
Andrew T. Fisher ◽  
Kenneth D. Mankoff ◽  
Slawek M. Tulaczyk ◽  
Scott W. Tyler ◽  
Neil Foley ◽  
...  
Keyword(s):  
Heat Flux ◽  
Ice Sheet ◽  
The West ◽  
Geothermal Heat ◽  
Antarctic Ice Sheet ◽  
West Antarctic Ice Sheet ◽  
Subglacial Lake ◽  
West Antarctic ◽  
Basal Melting ◽  
Subglacial Lake Whillans

The geothermal heat flux is a critical thermal boundary condition that influences the melting, flow, and mass balance of ice sheets, but measurements of this parameter are difficult to make in ice-covered regions. We report the first direct measurement of geothermal heat flux into the base of the West Antarctic Ice Sheet (WAIS), below Subglacial Lake Whillans, determined from the thermal gradient and the thermal conductivity of sediment under the lake. The heat flux at this site is 285 ± 80 mW/m2, significantly higher than the continental and regional averages estimated for this site using regional geophysical and glaciological models. Independent temperature measurements in the ice indicate an upward heat flux through the WAIS of 105 ± 13 mW/m2. The difference between these heat flux values could contribute to basal melting and/or be advected from Subglacial Lake Whillans by flowing water. The high geothermal heat flux may help to explain why ice streams and subglacial lakes are so abundant and dynamic in this region.

scholarly journals Subglacial erosion has the potential to sustain microbial processes in Subglacial Lake Whillans, Antarctica

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Beatriz Gill-Olivas ◽  
Jon Telling ◽  
Martyn Tranter ◽  
Mark Skidmore ◽  
Brent Christner ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Matter ◽  
High Energy ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Subglacial Lake ◽  
Microbial Ecosystems ◽  
High Concentrations ◽  
Subglacial Lake Whillans ◽  
Subsequent Addition

AbstractSubglacial Lake Whillans lies below around 800 m of Antarctic ice and is isolated from fresh sources of photosynthetic organic matter to sustain life. The diverse microbial ecosystems within the lake and underlying sediments are therefore dependent on a combination of relict, overridden, marine-derived organic matter and mineral-derived energy. Here, we conduct experiments to replicate subglacial erosion involving both gentle and high-energy crushing of Subglacial Lake Whillans sediments and the subsequent addition of anoxic water. We find that substantial quantities of reduced species, including hydrogen, methane, acetate and ammonium and oxidised species such as hydrogen peroxide, sulfate and carbon dioxide are released. We propose that the concomitant presence of both hydrogen and hydrogen peroxide, alongside high concentrations of mineral surface radicals, suggests that the splitting of water on freshly abraded mineral surfaces increases the concentrations of redox pairs from rock-water reactions and could provide a mechanism to augment the energy available to microbial ecosystems.

Subglacial Lake Whillans — Seismic observations of a shallow active reservoir beneath a West Antarctic ice stream

2012 ◽  
Vol 331-332 ◽  
pp. 201-209 ◽  
Author(s):  
Huw J. Horgan ◽  
Sridhar Anandakrishnan ◽  
Robert W. Jacobel ◽  
Knut Christianson ◽  
Richard B. Alley ◽  
...  
Keyword(s):  
Subglacial Lake ◽  
West Antarctic ◽  
Ice Stream ◽  
Subglacial Lake Whillans
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