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Mikucki JA, Schuler CG, Digel I, Kowalski J, Tuttle MJ, Chua M, Davis R, Purcell AM, Ghosh D, Francke G, Feldmann M, Espe C, Heinen D, Dachwald B, Clemens J, Lyons WB, Tulaczyk S. Field-Based Planetary Protection Operations for Melt Probes: Validation of Clean Access into the Blood Falls, Antarctica, Englacial Ecosystem. ASTROBIOLOGY 2023; 23:1165-1178. [PMID: 37962840 DOI: 10.1089/ast.2021.0102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Subglacial environments on Earth offer important analogs to Ocean World targets in our solar system. These unique microbial ecosystems remain understudied due to the challenges of access through thick glacial ice (tens to hundreds of meters). Additionally, sub-ice collections must be conducted in a clean manner to ensure sample integrity for downstream microbiological and geochemical analyses. We describe the field-based cleaning of a melt probe that was used to collect brine samples from within a glacier conduit at Blood Falls, Antarctica, for geomicrobiological studies. We used a thermoelectric melting probe called the IceMole that was designed to be minimally invasive in that the logistical requirements in support of drilling operations were small and the probe could be cleaned, even in a remote field setting, so as to minimize potential contamination. In our study, the exterior bioburden on the IceMole was reduced to levels measured in most clean rooms, and below that of the ice surrounding our sampling target. Potential microbial contaminants were identified during the cleaning process; however, very few were detected in the final englacial sample collected with the IceMole and were present in extremely low abundances (∼0.063% of 16S rRNA gene amplicon sequences). This cleaning protocol can help minimize contamination when working in remote field locations, support microbiological sampling of terrestrial subglacial environments using melting probes, and help inform planetary protection challenges for Ocean World analog mission concepts.
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Affiliation(s)
- J A Mikucki
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - C G Schuler
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - I Digel
- FH Aachen - Campus Jülich, Institute of Bioengineering, Julich, Nordrhein-Westfalen, Germany
| | - J Kowalski
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - M J Tuttle
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - M Chua
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - R Davis
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - A M Purcell
- Northern Arizona University, Flagstaff, Arizona, USA
| | - D Ghosh
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - G Francke
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - M Feldmann
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - C Espe
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - D Heinen
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - B Dachwald
- RWTH Aachen University, Aachen, North Rhine-Westfalia, Germany
| | - J Clemens
- University of Bremen, Bremen, Germany
| | - W B Lyons
- The Ohio State University, Byrd Polar Research Center, Columbus, Ohio, USA
| | - S Tulaczyk
- University of California Santa Cruz, Santa Cruz, California, USA
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Achberger AM, Christner BC, Michaud AB, Priscu JC, Skidmore ML, Vick-Majors TJ. Microbial Community Structure of Subglacial Lake Whillans, West Antarctica. Front Microbiol 2016; 7:1457. [PMID: 27713727 PMCID: PMC5032586 DOI: 10.3389/fmicb.2016.01457] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/31/2016] [Indexed: 11/13/2022] Open
Abstract
Subglacial Lake Whillans (SLW) is located beneath ∼800 m of ice on the Whillans Ice Stream in West Antarctica and was sampled in January of 2013, providing the first opportunity to directly examine water and sediments from an Antarctic subglacial lake. To minimize the introduction of surface contaminants to SLW during its exploration, an access borehole was created using a microbiologically clean hot water drill designed to reduce the number and viability of microorganisms in the drilling water. Analysis of 16S rRNA genes (rDNA) amplified from samples of the drilling and borehole water allowed an evaluation of the efficacy of this approach and enabled a confident assessment of the SLW ecosystem inhabitants. Based on an analysis of 16S rDNA and rRNA (i.e., reverse-transcribed rRNA molecules) data, the SLW community was found to be bacterially dominated and compositionally distinct from the assemblages identified in the drill system. The abundance of bacteria (e.g., Candidatus Nitrotoga, Sideroxydans, Thiobacillus, and Albidiferax) and archaea (Candidatus Nitrosoarchaeum) related to chemolithoautotrophs was consistent with the oxidation of reduced iron, sulfur, and nitrogen compounds having important roles as pathways for primary production in this permanently dark ecosystem. Further, the prevalence of Methylobacter in surficial lake sediments combined with the detection of methanogenic taxa in the deepest sediment horizons analyzed (34–36 cm) supported the hypothesis that methane cycling occurs beneath the West Antarctic Ice Sheet. Large ratios of rRNA to rDNA were observed for several operational taxonomic units abundant in the water column and sediments (e.g., Albidiferax, Methylobacter, Candidatus Nitrotoga, Sideroxydans, and Smithella), suggesting a potentially active role for these taxa in the SLW ecosystem. Our findings are consistent with chemosynthetic microorganisms serving as the ecological foundation in this dark subsurface environment, providing new organic matter that sustains a microbial ecosystem beneath the West Antarctic Ice Sheet.
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Affiliation(s)
- Amanda M Achberger
- Department of Biological Sciences, Louisiana State University, Baton Rouge LA, USA
| | - Brent C Christner
- Department of Biological Sciences, Louisiana State University, Baton RougeLA, USA; Department of Microbiology and Cell Science, University of Florida, GainesvilleFL, USA; Biodiversity Institute, University of Florida, GainesvilleFL, USA
| | - Alexander B Michaud
- Department of Land Resources and Environmental Science, Montana State University, Bozeman MT, USA
| | - John C Priscu
- Department of Land Resources and Environmental Science, Montana State University, Bozeman MT, USA
| | - Mark L Skidmore
- Department of Earth Sciences, Montana State University, Bozeman MT, USA
| | - Trista J Vick-Majors
- Department of Land Resources and Environmental Science, Montana State University, Bozeman MT, USA
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Makinson K, Pearce D, Hodgson DA, Bentley MJ, Smith AM, Tranter M, Rose M, Ross N, Mowlem M, Parnell J, Siegert MJ. Clean subglacial access: prospects for future deep hot-water drilling. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:rsta.2014.0304. [PMID: 26667913 PMCID: PMC4685967 DOI: 10.1098/rsta.2014.0304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/21/2015] [Indexed: 06/05/2023]
Abstract
Accessing and sampling subglacial environments deep beneath the Antarctic Ice Sheet presents several challenges to existing drilling technologies. With over half of the ice sheet believed to be resting on a wet bed, drilling down to this environment must conform to international agreements on environmental stewardship and protection, making clean hot-water drilling the most viable option. Such a drill, and its water recovery system, must be capable of accessing significantly greater ice depths than previous hot-water drills, and remain fully operational after connecting with the basal hydrological system. The Subglacial Lake Ellsworth (SLE) project developed a comprehensive plan for deep (greater than 3000 m) subglacial lake research, involving the design and development of a clean deep-ice hot-water drill. However, during fieldwork in December 2012 drilling was halted after a succession of equipment issues culminated in a failure to link with a subsurface cavity and abandonment of the access holes. The lessons learned from this experience are presented here. Combining knowledge gained from these lessons with experience from other hot-water drilling programmes, and recent field testing, we describe the most viable technical options and operational procedures for future clean entry into SLE and other deep subglacial access targets.
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Affiliation(s)
- Keith Makinson
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - David Pearce
- Faculty of Health and Life Sciences, University of Northumbria, Ellison Building, Newcastle upon Tyne NE1 8ST, UK
| | - Dominic A Hodgson
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Michael J Bentley
- Department of Geography, Durham University, Lower Mountjoy, South Road, Durham DH1 3LE, UK
| | - Andrew M Smith
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Martyn Tranter
- School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
| | - Mike Rose
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Neil Ross
- School of Geography, Politics and Sociology, Newcastle University, Newcastle Upon Tyne NE1 7RU, UK
| | - Matt Mowlem
- National Oceanography Centre, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH, UK
| | - John Parnell
- School of Geosciences, University of Aberdeen, King's College, Aberdeen AB24 3UE, UK
| | - Martin J Siegert
- Grantham Institute and Department of Earth Science and Engineering, Imperial College London, South Kensington SW7 2AZ, UK
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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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