Image of the Day
Success in the Field!
Mission accomplished for the WISSARD team, all shown here. Four holes drilled, and seismic, tilt, and temperature equipment deployed. They have packed up equipment and traversed back to the Subglacial Lake Whillans site, where they are packing and winterizing additional equipment. The whole team will fly to McMurdo in the next few days, followed by the 3-member traverse team, which will make the ~12 day trek. Image by Chad Carpenter, who used a timer and slid into place laying down in the front just in time. His antics made Graham, left, and Dan, right, laugh and even got Dennis to smile. Check out the TransAntarctic Mountains, behind. Beautiful. Job well done!
21 August 2014
An exciting paper by Brent Christner and the WISSARD Team was published in Nature this week. The editor's summary:
"Whether there is microbial life in subglacial lakes in the Antarctic has been a matter of controversy, as early results were compromised when it was discovered that contamination may have occurred during drilling. Discovered less than a decade ago using satellite data, Lake Whillans lies beneath some 800 metres of ice on the lower portion of the Whillans Ice Stream (WIS) in West Antarctica and is part of an extensive and evolving subglacial drainage network. In the first study to sample Antarctic subglacial waters directly, analysis of sediments obtained by the WISSARD drilling program shows that Lake Whillans' water contains more than 3,900 different types of bacteria and archaea, including one closely related to the nitrite oxidizing betaproteobacterium 'Candidatus Nitrotoga arctica', which comprised 13% of the sequence data. The lake waters contain a diverse range of metabolically active microorganisms, many of which seem to gain nutrients from the melting ice and from the rock and sediment beneath the ice."
Nature article on WISSARD by Doug Fox: http://www.nature.com/news/lakes-under-the-ice-antarctica-s-secret-garde...
NSF press release: http://www.nsf.gov/news/news_summ.jsp?cntn_id=132267
WISSARD Project Overview
Subglacial Aquatic Environments
Over the last several decades, by using ground penetrating radar and other remote sensing tools, scientists have discovered that under the massive Antarctic ice sheets there lies a vast hydrological system of liquid water. This water exists because geothermal heat flow from below, coupled with pressure, movement, and the insulating nature of the ice sheet above, is great enough to maintain some areas at the base of the ice sheet above the freezing point, even in the extreme cold of Antarctica. In topographic depressions there are hundreds of lakes, both large and small; some are isolated, but many are interconnected by water channels and large areas of saturated sediments, the water eventually running out into the Southern Ocean as the ice sheet becomes a floating ice shelf.
In order to explore one of these hydrological systems at the margin of the West Antarctic Ice Sheet, we have organized an interdisciplinary project to access the subglacial environment. The Whillans Ice Stream Subglacial Access Research Drilling project (WISSARD) is using a variety of tools and techniques to explore Subglacial Lake Whillans and the nearby grounding zone, on the southeastern edge of the Ross Sea. Radar and seismic equipment is used to profile the overlying ice sheet and the underlying water, sediments, and rock, while GPS stations accurately track ice movement.
Continued geophysical surveying is the focus of the 2013-2014 season. Two sites on the Whillans Ice Stream will be investigated. At each site a mobile, hot water drill will be used to create 15 cm holes, 750 meters in depth where borehole sesimic, tilt, and heat sensors will be deployed and left to collect long-term data. Surface seismic sensors will also be installed, to add to the network of GPS and active seismic stations monitored on the surface of the ice stream to help characterize the movement of ice and the conditions of the ice at the base of the ice stream.