Geophysical exploration of a West Antarctic subglacial lake

Lead Research Organisation: British Antarctic Survey
Department Name: Physical Sciences

Abstract

Antarctic subglacial lakes are liquid bodies of water located in topographic hollows beneath the ice sheets of Antarctica. They have attracted considerable scientific interest over the last ten years as they are expected to contain unique microbial lifeforms and detailed records of past climate change. Examination of these contents requires scientists to penetrate into a lake, and measure and sample the lake water and sediment. No lake has yet to be explored in this way, however. This form of direct analysis can only take place once a lake has been characterised fully by geophysical methods (to uncover the morphology of the ice base and the water depth of the lake). Of the 145 known subglacial lakes in Antarctica none have been measured to the level required for meaningful direct analysis to take place. We propose to undertake a comprehensive geophysical exploration of a 10 km long subglacial lake in West Antarctica, near the Ellsworth Mountains, named Subglacial Lake Ellsworth. The result of the project will be the first fully characterised subglacial lake environment and the establishment of a candidate for future direct exploration. Data analysis and modelling will be undertaken at the University of Bristol, the British Antarctic Survey and Northumbria University. Ice thickness will be determined from ice-penetrating radar, water depths will be found using seismic exploration, and ice flow and accumulation will be obtained from direct surface measurements. A series of numerical models will be used to understand the history of the lake, the flow of ice across the lake and the circulation of water within the lake. Data visualisation will be undertaken in conjunction with Dr. Martin Jakobsson (collaborator). Following this project, the next step will be to send a probe into Lake Ellsworth. A UK-led team has been assembled to plan such work (see www.ggy.bris.ac.uk/ellsworth), and take on what is arguably the most eagerly awaited and high-profile scientific project in the history of Antarctic science. Hence, the geophysical work we propose here will be thought of, in years to come, as a hugely important first step towards the understanding of one of the greatest unexplored habitats on Earth.

Publications

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Siegert, Martin J.; Kennicutt, Mahlon C., II; Bindschadler, Robert A. (2011) Antarctic Subglacial Aquatic Environments

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Siegert, Martin J.; Kennicutt, Mahlon C., II; Bindschadler, Robert A. (2011) Antarctic Subglacial Aquatic Environments

 
Description Sediments could record life in an Antarctic subglacial lake Sediments found at the bed of an Antarctic subglacial lake could contain a record of unique life-forms in the lake and a history of how the Antarctic Ice Sheet has changed in the past. Surveys carried out over Subglacial Lake Ellsworth confirm there is a thick pile of sediments at the lake bed, which have probably accumulated there slowly over thousands of years. In the search for unique life-forms in subglacial lakes, the presence, or absence of these sediments is important because this is where the evidence for both micro-organisms living in the lake, and changes in the ice sheet are believed to become trapped; if no sediments exist, then this evidence will be lost. Analysis of seismic data collected over Subglacial Lake Ellsworth has confirmed the presence of a layer of sediments up to 70 m thick at the lake bed. This was crucial information for the team who tried to drill into the lake in January 2013; it identified the best place to drill and also helped design the equipment built to capture sediment samples from the lake bed.
Exploitation Route Lake Exploration missions need to know the exact dimensions of the lake environment if they are to be planned properly. The results from this project allow such planning to take place.
Sectors Environment

Pharmaceuticals and Medical Biotechnology

 
Description This research contributed to the SCAR code of conduct on Antarctic subglacial exploration, adopted by the Antarctic Treaty in 2012.
First Year Of Impact 2012
Sector Environment
Impact Types Policy & public services

 
Title Ice surface, ice base and lake bed elevation data from seismic data acquired over Subglacial Lake Ellsworth 2007-08 
Description Point data measurements of ice surface, ice base and lake bed elevation are given from Subglacial Lake Ellsworth (SLE), West Antarctica. The data were acquired during the austral summer of 2007-2008. Five seismic reflection lines were acquired over SLE, with surface elevation determined by dual frequency GPS. Funding was provided by NERC AFI, award numbers NE/D009200/1, NE/D008638/1 and NE/D008751/1. Logistics support: British Antarctic Survey. Equipment support: NERC Geophysical Equipment Facility (loan numbers 838 and 870). 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
 
Title Subglacial lakes and hydrology across the Ellsworth Subglacial Highlands, West Antarctica, 1977-2017 
Description A new subglacial bed Digital Elevation Model (DEM) from Ellsworth Subglacial Highlands (ESH) was created from previously gridded bed elevation data and new unpublished radar data. The new DEM includes the upper reaches of Pine Island Glacier, Rutford and Institute Ice Streams and reveals new topographical features. The main findings on this new DEM are two linear deep throughs with a perpendicular transection valley near Subglacial Lake Ellsworth. Additionally, using the new DEM and ice surface elevation data from CryoSat2 ice surface DEM, a hydropotential model was built and used to create a detailed hydropotential model of ESH to simulate the subglacial hydrological network. This approach allowed us to characterize basal hydrology, subglacial water catchments and connections between them. In this characterization we noticed the mismatch between subglacial hydrological catchment and ice surfaces catchment of Rutford Ice Stream, Pine Island Glacier and Thwaites Glacier. Funding was provided by NERC Antarctic Funding Initiative (AFI) grants NE/D008751/1, NE/D009200/1, and NE/D008638/1, and NERC grant NE/G013071/1. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
 
Description DECC talk, why is Antarctica changing? 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Policymakers/politicians
Results and Impact An invited talk to DECC on how Antarctica is changing and why we should care
Year(s) Of Engagement Activity 2015
 
Description Inaugural Lecture 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Lots of questions from the public

Emails and twitter questions
Year(s) Of Engagement Activity 2015
URL https://search.yahoo.com/search;_ylt=AwrBT.E48QNWo04AaNhXNyoA;_ylc=X1MDMjc2NjY3OQRfcgMyBGZyA3lzZXRfY...
 
Description Pint of Science 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Many questions from the public about my talk

Emails, and social media contact, from the public about my talk
Year(s) Of Engagement Activity 2015
URL http://pintofscience.co.uk/event/undiscovered-origins/
 
Description Royal Society Meeting on Subglacial Lake Exploration 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation workshop facilitator
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact International dialogue on the future of Antarctic subglacial lake exploration.
Article in Eos on the findings of the workshop.
A white paper detailing the 20 year future for subglacial lake exploration, fed to the Antarctic Roadmap Challenge to integrate with other long-term plans for exploration.
A Royal Society book to document progress and plans.

A high degree of community shared knowledge.
A meeting with the Korean Antarctic Programme on subglacial exploration.
Year(s) Of Engagement Activity 2015
URL https://royalsociety.org/events/2015/03/subglacial-antarctic-lakes/
 
Description Science Uncovered 2016 - exploration of East Antarctica 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact The ICECAP2 programme ran a exhibit at the Natural History Museum's Science Uncovered event, London, 30 September 2016. The audience was in the 1000s, and come from the public, academic, policy and businesses.
The exhibit demonstrated how polar exploration is undertaken, what the results are and how they are important for understanding sea level change.
Year(s) Of Engagement Activity 2016
URL http://www.nhm.ac.uk/visit/whats-on/programs/nhm/science_uncovered_2016.html?date=30.09.2016