Subglacial Antarctic Lake Environments (SALE)
2008 Progress Report
The SCAR Scientific Research Program (SRP) on Subglacial Antarctic Lake Environments (SALE) made significant advances on several fronts in 2008. SALE promotes, facilitates and champions international cooperation to better understand subglacial aquatic environments in Antarctica. In addition, SALE promotes and advances all aspects of environmental stewardship in research and exploration of these unique settings. SALE is a recognized IPY program under the auspices of the SALE-UNified International Team for Exploration and Discovery (SALE-UNITED) program. The SALE website contains details on all facets of the Program (http://scarsale.tamu.edu/). SALE produces an email digest mailing that circulates weekly highlights of subglacial lake research and related topics to more than 150 scientists world-wide.
SALE facilitates partnerships and cooperation. Members of SALE are funded through their national programmes to conduct the science of SALE. SALE funding from SCAR allows for the convening of a yearly meeting. As such, the achievements of SALE are produced by a cohort of national efforts. Knowledge of subglacial aquatic environments has reached a level where major proposals are now being submitted for funding by individual national programs beyond remote surveys. These proposed research projects, if funded, will sample subglacial systems in compliance with current environmental protocols. Data obtained from these projects will provide the basis for future research and discovery. The following highlights two recent proposals (one funded and one pending) and updates that status of drilling activities at Vostok Station:
1. Subglacial Lake Ellsworth: In Dec 2008, UK-NERC awarded funding for the direct access, measurement and sampling of Subglacial Lake Ellsworth. This £6.7M programme involves a broad consortium of ten UK universities and research institutes, and three US institutions. The project will access the lake using hot water drilling designed to penetrate the lake's ice roof without contaminating the water body below. A probe will then enter the lake and collect measurements and samples. A gravity core will subsequently be deployed into the lake floor, collecting a 2-3 m sediment core. Instrument development and testing, and a comprehensive environmental evaluation (presented to the Antarctic Treaty System), will be completed over the next three years. The lake access experiment will be conducted in 2012/13.
2. West Antarctic Ice Streams: The US has prepared three linked proposals that are currently under review by the US National Science Foundation-Office of Polar Programs. These interrelated proposals use an interdisciplinary science approach to study the subglacial environment under two West Antarctic ice streams. Direct sampling will yield seminal information on the glaciological, geological and microbial dynamics of these environments and test the overarching hypothesis that the hydrology in these environments exerts a major control on ice sheet dynamics, geochemistry, metabolic and phylogenetic diversity, and biogeochemical transformations of major elements.
a) The “Lake and Ice Stream Subglacial Access Research Drilling” (LISSARD) proposal will investigate subglacial hydrology and geochemistry in lakes located beneath Mercer and Whillans ice streams.
b) The “Robotic Access to Grounding-zones for Exploration and Science” (RAGES) proposal will concentrate on studying nearby hydraulically-linked ice stream grounding zones.
c) The “GeomicroBiology of Antarctic Subglacial Environments” (GBASE) proposal will focus on metabolic and phylogenetic diversity, and associated biogeochemical transformations within these subglacial systems.
The three proposals are connected scientifically through common interest in coupled fluxes of ice, sediments, nutrients and liquid water through the subglacial environment. There is a common need for each project to characterize and quantify physical, chemical and biological processes within the subglacial system. At the practical level, the proposals are connected through shared scientific personnel, planned use of the same basic drilling and sampling technologies, and concentration of field logistics in the same geographical region (lower sections of Whillans and Mercer Ice Streams). The teams represented by all proposals collectively will engage in close collaboration and exchange of scientific ideas in the field, at annual workshops and during publication. If funded, the subglacial environment will be sampled during the 2010-2011 field season.
3. Subglacial Lake Vostok: The Russian Antarctic drilling program at Lake Vostok continues to make progress. In 2008 the Russian studies at Vostok Station were carried out in the framework of two Antarctic seasons 2007-08 and 2008-09. They consisted of drilling operations in the borehole 5G-1 (both seasons), radio-echo sounding and seismic studies during the season 2007-2008. The radio-echo sounding in the Lake Vostok area was finished in January 2008 and an accurate map of the coastline of the lake and a 3-D picture of the water layer thickness were obtained. The results were presented at the SCAR Conference in July 2008 in St. Petersburg. Seismic studies of the water layer and sediment rock thickness using reflected waves were also finished in January 2008. During the current season, 2008-09, radio-echo sounding will be conducted outside of the lake limits. Preparations are underway to conduct seismic measurements of the geological structure of the Earth's crust using refracted wave methodologies.
In January 2008, the Russian drill operators increased the drilling fluid density and its level above the damaged drill, which is at 3666 m. Specialists of the St. Petersburg Mining Institute received equipment to extract the damaged drill from the hole in December 2008. Using this modified equipment, Russian drillers increased the hole diameter from 132 mm to 139 mm in the bottom 200 m of the borehole and began filling the hole with antifreeze. The plan is to extract the drill in January 2009 so that drilling operations can continue with a modified drill that has been designed for warm, monocrystaline ice.
In addition to projects to directly access subglacial environments, US NASA has funded development of a sub-ice robot (“Endurance”) designed to characterize the physical and chemical environment of subglacial lakes on Earth as well as other icy worlds such as Europa. Endurance was successfully deployed in November and December 2008 in the west lobe of Lake Bonney (McMurdo Dry Valleys) collecting the first 3-dimensional data on a permanently ice-covered lake. The robot also successfully mapped the snout of the Taylor Glacier where it intersects with the liquid water of Lake Bonney.
Belgian modellers continue to synthesize and integrate data to better understand the deglaciation history of the Antarctic ice sheet and the mechanisms involved in grounding line migration. Current research focuses on ice rises (pinning points) along coastal Dronning Maud Land (DML), Antarctica. Modelling efforts are based on radar data to define how long the ice flow remained local on the ice rise, which will constrain the deglaciation history of the DML sector. Results of combined radar and ice analysis allow determination of whether pinning points play a stabilizing role in the dynamics of grounding lines and the role of marine ice. This research will improve present-day ice sheet models that incorporate grounding line migration. Furthermore, regional ice sheet model experiments focusing on the DML sector will refine quantification of the contribution of this area to sea level rise over the last 20 ka. The project started with field work in November-December 2008 when >150km of radar data were collected and several tens of meters of ice cores were collected at the contact between meteoric and marine ice, close to the grounding line.
During the last year, SALE has:
• built a community through workshops, meetings, and sessions at scientific meetings;
• identified major scientific and technological goals for SALE research and exploration through active engagement of the community;
• held regular meetings that serve as forums for the discussion of science and technology amongst national programmes
• educated the public through extensive and sustained coverage of SALE science in the lay and scientific press;
• provided a framework for the development of a code of conduct for Antarctic subglacial exploration. SCAR has designated an action group to finalize this plan by early 2009; and
• proposed, and have had accepted the staging of an American Geophysical Union Chapman Conference in 2010 on subglacial aquatic environments that will be chronicled in a special AGU monograph
SALE continues to contribute to the IPY as a recognized IPY Programme as SALE – the Unified International Team for Exploration and Discovery (SALE-UNITED) (http://www.ipy.org/index.php?ipy/detail/sale_united/). The number of SALE related publications in peer-reviewed journals is increasing each year. Lists of publications by year are maintained at the SCAR SALE web site (http://scarsale.tamu.edu/selected-publications). Two major review papers (Priscu et al. 2008; Bell 2008) were published in 2008 that summarized much of what is known about subglacial ecosystems. Many important articles have been published in Science and Nature on various aspects of SALE science authored by SALE participants and collaborators during the last few years.
1. The next SALE meeting will take place in Brussels, Belgium in June 2009. This meeting will incorporate a new format where we will focus on a major aspect of SALE science and a programme of invited speakers will be developed. The outcome from each meeting will be summarized in a white paper and submitted for publication in a journal.
2. The SALE meetings will include students from the local organizers for each meeting and these invitee lists will be developed in consultation with local APECS representatives.
3. SALE will continue to propose and organize sessions at major earth and polar science meetings and venues such as the one help during the 2008 Fall AGU meeting in San Francisco and the subglacial science session held at the SCAR/IASC IPY Conference in St. Petersburg in July 2008.
4. SALE sessions will be proposed for the AGU and EGU meetings in 2009/2010.
5. An application for an AGU Chapman Conference entitled “Exploration And Study Of Antarctic Sub-glacial Aquatic Environments” was funded. This important conference will be held in Washington, DC in 2010 in conjunction with that year’s SALE meeting.
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Sunday, 01 February 2009 20:56
Subglacial Antarctic Lake Environments (SALE) - 2008 progress reportWritten by Louise Huffman
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