Governance of the exploration of subglacial Antarctica
TL;DR: The Antarctic Treaty Consultative Meeting (ATC) has been used to guide responsible scientific exploration and stewardship of pristine subglacial lakes as discussed by the authors, and the Antarctic Treaty Parties agreed to its use and dissemination, ensuring that exploration and access is undertaken in a responsible, defensible and fact-based manner.
Abstract: Subglacial lakes, and their surrounding aqueous environments, are known to be viable yet extreme habitats for microbial life that may hold records of climate change spanning hundreds of thousands of years. Since the detection of Lake Vostok in 1996 plans have been developed to access, sample and monitor these unique environments. Critical to these plans is assurance that contamination and disturbance is minimized in all aspects of the activity. Precisely how this is achieved has been a matter of international debate for many years culminating in the formulation of a ‘Code of Conduct’ to guide responsible scientific exploration and stewardship of these pristine systems by the Scientific Committee on Antarctic research. The Code of Conduct was first introduced to the Antarctic Treaty Consultative Meeting in 2011, influencing planning for three exploration programmes. In May 2018, following several recent and operational advances, Antarctic Treaty Parties agreed to its use and dissemination, ensuring that subglacial lakes exploration and access is undertaken in a responsible, defensible and fact-based manner. As our knowledge of subglacial lakes improves, so too will our appreciation of their scientific value and potential vulnerability. In other regions of Antarctica where value and vulnerabilities are high, Antarctic Specially Protected Areas and Antarctic Specially Managed Areas ensure long-term protection whilst allowing scientific access and study. Such governance models will be applicable to the conservation and protection of subglacial lake systems as scientific understanding of their form and functioning advances.
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Texas A&M University1, Ohio State University2, Norwegian Polar Institute3, British Antarctic Survey4, Commonwealth Scientific and Industrial Research Organisation5, Imperial College London6, University of Western Australia7, University of Colorado Boulder8, South Asian University9, Royal Holloway, University of London10, Victoria University of Wellington11, Instituto Antártico Chileno12, Desert Research Institute13, Scientific Committee on Antarctic Research14, University of California, Los Angeles15, Stanford University16, University of California, San Diego17, Australian National University18, Merrimack College19
TL;DR: The view from the south is, more than ever, dominated by ominous signs of change as mentioned in this paper, and a renewed commitment to gathering further knowledge will quicken the pace of understanding of Earth systems and beyond.
Abstract: The view from the south is, more than ever, dominated by ominous signs of change. Antarctica and the Southern Ocean are intrinsic to the Earth system, and their evolution is intertwined with and influences the course of the Anthropocene. In turn, changes in the Antarctic affect and presage humanity's future. Growing understanding is countering popular beliefs that Antarctica is pristine, stable, isolated, and reliably frozen. An aspirational roadmap for Antarctic science has facilitated research since 2014. A renewed commitment to gathering further knowledge will quicken the pace of understanding of Earth systems and beyond. Progress is already evident, such as addressing uncertainties in the causes and pace of ice loss and global sea-level rise. However, much remains to be learned. As an iconic global “commons,” the rapidity of Antarctic change will provoke further political action. Antarctic research is more vital than ever to a sustainable future for this One Earth.
63 citations
Cites background from "Governance of the exploration of su..."
...Ice coring is internationally coordinated(93) and, while these activities focus on retrieving ice samples for paleoclimate records, access to and sampling of the underlying bed are essential for validating models.(94) A rock-coring project to extend records of climate to the interior of the continent remains an aspiration....
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TL;DR: In this paper, the key technologies and the instrumentation required for the subsurface exploration of ocean worlds are discussed and the focus is laid on Jupiter's moon Europa and Saturn's moon Enceladus.
Abstract: In this chapter, the key technologies and the instrumentation required for the subsurface exploration of ocean worlds are discussed The focus is laid on Jupiter’s moon Europa and Saturn’s moon Enceladus because they have the highest potential for such missions in the near future The exploration of their oceans requires landing on the surface, penetrating the thick ice shell with an ice-penetrating probe, and probably diving with an underwater vehicle through dozens of kilometers of water to the ocean floor, to have the chance to find life, if it exists Technologically, such missions are extremely challenging The required key technologies include power generation, communications, pressure resistance, radiation hardness, corrosion protection, navigation, miniaturization, autonomy, and sterilization and cleaning Simpler mission concepts involve impactors and penetrators or – in the case of Enceladus – plume-fly-through missions
26 citations
TL;DR: A change in microbial community structure with geographical location was apparent and, notably, a decrease in alpha diversity at more remote southern latitudes and soil-related microorganisms dominated microbial assemblages suggesting terrestrial input, most likely from long-range aeolian transport into continental Antarctica.
Abstract: It was once a long-held view that the Antarctic was a pristine environment with low biomass, low biodiversity and low rates of microbial activity. However, as the intensity of scientific investigation has increased, so these views have started to change. In particular, the role and impact of human activity toward indigenous microbial communities has started to come under more intense scrutiny. During the Lake Ellsworth drilling campaign in 2012, a microbiological survey was conducted to determine the extent and likelihood of exogenous input into the subglacial lake system during the hot water drilling process. The results of this study showed that snow used to provide melt water differed in its microbiological composition from that of the surrounding area and raised the question of how the biogeography of snow-borne microorganisms might influence the potential outcome of scientific analyses. In this study, we investigated the biogeography of microorganisms in snow around a series of Antarctic logistic hubs, where human activity was clearly apparent, and from which scientific investigations were undertaken. Snow was collected from the surface to represent the collections during melt water production for hot water drilling. A change in microbial community structure with geographical location was apparent and, notably, a decrease in alpha diversity at more remote southern latitudes. Soil-related microorganisms dominated microbial assemblages suggesting terrestrial inputs, most likely from long-range aeolian transport into continental Antarctica. We also observed that relic DNA was not a major issue when assessing snow samples. Overall, our observations might have profound implications for future scientific activities in Antarctica, such as the need to establish 'no-go' protected areas, the need for better characterization of field sites or better protocols for sterilization and verification of ice drilling equipment.
17 citations
Cites background from "Governance of the exploration of su..."
...When undertaking research aimed at detecting life in extreme environments, such as in subglacial lakes, we believe it is important to consider how the indigenous microbial communities may be affected across the field site as well as with in subglacial targets themselves (Siegert and Kennicutt, 2018)....
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01 Apr 2019
TL;DR: In this paper, the authors used a low-frequency radar on the Mars Express spacecraft to search for liquid water in Mars' southern ice cap and found that the water is probably kept from freezing by dissolved salts and the pressure of the ice above.
Abstract: Liquid water under Mars' southern ice cap Mars is known to host large quantities of water in solid or gaseous form, and surface rocks show clear evidence that there was liquid water on the planet in the distant past. Whether any liquid water remains on Mars today has long been debated. Orosei et al. used radar measurements from the Mars Express spacecraft to search for liquid water in Mars' southern ice cap (see the Perspective by Diez). They detected a 20-km-wide lake of liquid water underneath solid ice in the Planum Australe region. The water is probably kept from freezing by dissolved salts and the pressure of the ice above. The presence of liquid water on Mars has implications for astrobiology and future human exploration. Science, this issue p. 490; see also p. 448 Radar data from Mars Express show that there is a lake of liquid water underneath the solid ice of Mars’ southern ice cap. The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.
15 citations
TL;DR: In this paper, the BEAMISH hot water drill was used to access Subglacial Lake CECs (SLCECs) in West Antarctica to meet the requirements of the Scientific Committee on Antarctic Research code of conduct.
Abstract: Recent drilling successes on Rutford Ice Stream in West Antarctica demonstrate the viability of hot water drilling subglacial access holes to depths >2000 m. Having techniques to access deep subglacial environments reliably paves the way for subglacial lake exploration beneath the thick central West Antarctic Ice Sheet. An ideal candidate lake, overlain by ~2650 m of ice, identified by Centro de Estudios Cientificos (CECs), Chile, has led to collaboration with British Antarctic Survey to access Subglacial Lake CECs (SLCECs). To conform with the Scientific Committee on Antarctic Research code of conduct, which provides a guide to responsible scientific exploration and stewardship of these pristine systems, any access drilling must minimise all aspects of contamination and disturbance of the subglacial environment. To meet these challenges, along with thicker ice and 2000 m elevation, pumping and water treatment systems developed for the Subglacial Lake Ellsworth project, together with new diesel generators, additional water heating and longer drill hose, are currently being integrated with the BEAMISH hot water drill. A dedicated test season near SLCECs will commission the new clean hot water drill, with testing and validation of all clean operating procedures. A subsequent season will then access SLCECs cleanly.
14 citations
Cites background or methods from "Governance of the exploration of su..."
...…all aspects of contamination and disturbance of the subglacial environment in compliance with the Scientific Committee on Antarctic Research (SCAR) code of conduct, which provides a guide to responsible scientific exploration and stewardship of these pristine systems (Siegert and Kennicutt, 2018)....
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...Key goals of Antarctic subglacial lake research are to cleanly access and sample the lake water and sediments to understand these subglacial aquatic environments with minimal disturbance and contamination (Siegert and Kennicutt, 2018)....
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...By integrating components of the SLE CHWD (Siegert and others, 2012) into the successful BEAMISH hot water drill (Anker and others, 2021), supplemented with new equipment and systems, the new SLCECs CHWD is being developed to meet the SCAR cleanliness protocols (Siegert and Kennicutt, 2018)....
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...This is critical for complying with the SCAR code of conduct (Siegert and Kennicutt, 2018) and ensuring samples taken from SLCECs are not compromised....
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References
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TL;DR: Bacterial 16S ribosomal DNA genes revealed low diversity in the gene population, and phylotypes were closely related to extant members of the alpha- and beta-Proteobacteria and the Actinomycetes.
Abstract: Data from ice 3590 meters below Vostok Station indicate that the ice was accreted from liquid water associated with Lake Vostok. Microbes were observed at concentrations ranging from 2.8 × 10 3 to 3.6 × 10 4 cells per milliliter; no biological incorporation of selected organic substrates or bicarbonate was detected. Bacterial 16 S ribosomal DNA genes revealed low diversity in the gene population. The phylotypes were closely related to extant members of the alpha - and beta - Proteobacteria and the Actinomycetes. Extrapolation of the data from accretion ice to Lake Vostok implies that Lake Vostok may support a microbial population, despite more than 10 6 years of isolation from the atmosphere.
411 citations
TL;DR: In this paper, an airborne radio-echo survey of ice depths over central East Antarctica led to the discovery of a sub-ice lake of unknown depth and composition, with an area of about 10,000km2 and lying beneath ∼4km of ice.
Abstract: IN 1974–75, an airborne radio-echo survey of ice depths over central East Antarctica led to the discovery of a sub-ice lake of unknown depth and composition, with an area of about 10,000km2 and lying beneath ∼4km of ice1. In 1993, altimetric data from satellite measurements2 provided independent evidence of the lake's areal extent, thus confirming it to be the largest known sub-ice lake by an order of magnitude. Here we analyse new altimetric and radio-echo data, along with existing seismic data3, to show that the lake is deep (mean depth of 125 m or more) and fresh, and that it has an area that exceeds previous estimates by about 50%—dimensions comparable with those of Lake Ontario. We estimate that the residence time of the water in the lake is of the order of tens of thousands of years, and that the mean age of water in the lake, since deposition as surface ice, is about one million years. Regional ice-dynamics can be explained in terms of steady-state ice flow along and over the lake.
342 citations
"Governance of the exploration of su..." refers background in this paper
...Covered by more than 4 km of ice, Lake Vostok is over 200 km in length, 80 km in width and, at one location, is filled with water to a depth of more than 500m (Kapitsa et al., 1996)....
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TL;DR: Radar data from Mars Express show that there is a lake of liquid water underneath the solid ice of Mars’ southern ice cap, and this feature has high relative dielectric permittivity, matching that of water-bearing materials, which is interpreted as a stable body of liquidWater on Mars.
Abstract: The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.
312 citations
18 Dec 1969-Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences
TL;DR: In this article, a traverse over the ice sheet of north western Greenland in 1964, during which a continuously recorded profile of ice thickness was obtained for the first time, was presented.
Abstract: Experimental results are presented from a traverse over the ice sheet of north western Greenland in 1964, during which a continuously recorded profile of ice thickness was obtained for the first time. Interpretation of data from this traverse is consistent with results of subsequent work to December 1967. The parameters of the apparatus are presented briefly, while the details of electronic circuits are being published separately. Theoretical problems of radio wave propagation in an ice sheet and, in particular, the factors affecting accuracy are discussed. The uncertainty in depth, over a small area, is ±5 m ±1.5% and this is verified by comparison with the seismic results for a range of depths up to 1.5 km. It is found that the only real uncertainty arises in irregular terrain. The effectiveness of the radio echo technique is dependent on the absorption of radio waves in ice. Temperature, and to a lesser extent the impurity content of ice, appear to be the main variables affecting field performance. Earlier laboratory results on the variation of absorption with temperature for ice cores from northwest Greenland, together with theoretically predicted temperature distributions throughout the ice mass, have provided estimates of the total loss by absorption. These estimates are reasonably consistent with the observed echo strengths over most of the traverse. Consequently, it is predicted that echoes can be obtained over considerable areas of the ice sheets of Greenland and Antarctica, as has been verified by subsequent observations. The reflexion coefficient at the ice/rock interface is of the order of —15 dB. It could rise to 0 dB for an ice/water interface and one area was found in Greenland where it appeared to fall to — 30 dB. Results from this traverse have shown that local surface slopes on the ice sheet are largely controlled by variations of longitudinal stress along the line of flow. Regional slopes over several kilometres vary with the velocity of movement of the ice, but appear to be less dependent on basal ice temperatures than laboratory results would suggest. The velocity of ice movement increases in proportion to the square or cube of the basal shear stress, but the stress itself shows no obvious dependence on basal ice temperature. Partially reflecting layers discovered within the ice mass are discussed mainly in terms of small density variations between adjacent layers of ice. One particularly prominent layer is calculated to be about 1000 years old and its variation of depth with position provides evidence in favour of the steady state model of the ice sheet.
272 citations
TL;DR: Analysis of lake ice frozen to the underside of the ice sheet above Lake Vostok, the largest of these lakes, has allowed inferences to be made on lake water chemistry and has revealed small quantities of microbes, suggesting that Lake Vstok is an extreme, yet viable, environment for life.
Abstract: Over 70 lakes have now been identified beneath the Antarctic ice sheet. Although water from none of the lakes has been sampled directly, analysis of lake ice frozen (accreted) to the underside of the ice sheet above Lake Vostok, the largest of these lakes, has allowed inferences to be made on lake water chemistry and has revealed small quantities of microbes. These findings suggest that Lake Vostok is an extreme, yet viable, environment for life. All subglacial lakes are subject to high pressure (∼350 atmospheres), low temperatures (about -3 °C) and permanent darkness. Any microbes present must therefore use chemical sources to power biological processes. Importantly, dissolved oxygen is available at least at the lake surface, from equilibration with air hydrates released from melting basal glacier ice. Microbes found in Lake Vostok's accreted ice are relatively modern, but the probability of ancient lake-floor sediments leads to a possibility of a very old biota at the base of subglacial lakes.
239 citations