Lake Vostok, Antarctica: Exploring a Subglacial Lake and Searching for Life in an Extreme Environment

Petit, Jean‐Robert; Alekhina, Irina A.; Булат, С. А.

doi:10.1007/10913406_8

Cited by 27 publications

(33 citation statements)

References 88 publications

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“…This high geothermal heat flow value is atypical for Precambrian shields 44 believed to cover most of Greenland. The recent indications of bacterial life in and under Antarctic ice 45 have revealed that the Earth possibly contains a previously unrecognized cold biosphere that would be actively involved in biogeochemical processes. Thus Greenland, like Antarctica, is now known to have liquid water at its base in some locations, water that awaits further study for basal sediment composition and evidence of life in a truly extreme environment.…”

Section: Basal Water Under the Icementioning

confidence: 99%

High-resolution record of Northern Hemisphere climate extending into the last interglacial period

2004

Nature

2,555

511

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Two deep ice cores from central Greenland, drilled in the 1990s, have played a key role in climate reconstructions of the Northern Hemisphere, but the oldest sections of the cores were disturbed in chronology owing to ice folding near the bedrock. Here we present an undisturbed climate record from a North Greenland ice core, which extends back to 123,000 years before the present, within the last interglacial period. The oxygen isotopes in the ice imply that climate was stable during the last interglacial period, with temperatures 5 8C warmer than today. We find unexpectedly large temperature differences between our new record from northern Greenland and the undisturbed sections of the cores from central Greenland, suggesting that the extent of ice in the Northern Hemisphere modulated the latitudinal temperature gradients in Greenland. This record shows a slow decline in temperatures that marked the initiation of the last glacial period. Our record reveals a hitherto unrecognized warm period initiated by an abrupt climate warming about 115,000 years ago, before glacial conditions were fully developed. This event does not appear to have an immediate Antarctic counterpart, suggesting that the climate see-saw between the hemispheres (which dominated the last glacial period) was not operating at this time.

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Section: Basal Water Under the Icementioning

confidence: 99%

High-resolution record of Northern Hemisphere climate extending into the last interglacial period

2004

Nature

2,555

511

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“…Due to the horizontal temperature gradient along the lake's ceiling, frazil crystals form in supercooled conditions and accrete on the glacier's bottom [Souchez et al, 2000]. An additional (hydrothermal) water source is believed to contribute to the lake's isotopic balance [Bulat et al, 2004;Petit et al, 2005]. The model thus takes into account the possibility of noncomplete mixing of glacier meltwater with the resident lake water, the contribution of two water sources, as well as nonstationary scenarios of the LV system.…”

Section: Description Of the Modelmentioning

confidence: 99%

“…We assume the hydrothermal circulation is fed by the lake water, thus does not influencing the mass balance of the lake. R is the isotopic content of melt, resident and hydrothermal waters (corresponding subscripts melt, l and HT), while a is an effective fractionation coefficient at the water-ice interface assuming that the lake ice is formed by three processes: frazil ice accretion, slow freezing of host water in equilibrium with ice, and freezing of water pocket [Petit et al, 2005;Souchez et al, 2000]. The coefficient a may theoretically change between 1 (for ice only formed by fastly growing frazil crystals under strong supercooling conditions or frozen water pockets) and 1.0208/1.003 (dD/d 18 O) for ice formed in equilibrium with water.…”

Section: Description Of the Modelmentioning

confidence: 99%

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Insights into hydrological regime of Lake Vostok from differential behavior of deuterium and oxygen‐18 in accreted ice

et al. 2010

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[1] We use isotopic data (deuterium and oxygen-18) of the recently recovered deepest Vostok ice core section (down to 3650 m depth) to study processes leading to the formation of lake ice and the hydrological regime of subglacial Lake Vostok. The significant variability of the lake ice isotopic content implies fluctuations in physical conditions of ice formation (mainly, volume and/or growth rate of frazil ice crystals) as well as variations of the isotope composition of the freezing water. The latter implies a poor mixing of the source waters (glacier melt and hydrothermal water) with the water of the main lake body. Poor mixing within the lake may have important consequences for the lake's chemical and gas balance and, particularly, for its microbiological content. A poorly mixed lake may provide ecological niches where microbial life can hide from high oxygen concentrations likely typical for the lake. We also show that the isotopic content of the main lake's input (meltwater) significantly differs from that of the output (lake ice), which can be explained by the contribution of an additional (hydrothermal) source. This latter conclusion is supported by the observed noncovariant behavior of deuterium and oxygen-18 isotopes in the lake ice.

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“…Finally, the multidisciplinary approach that has been developed for searching for life in the Lake Vostok ice leads to some guiding principles that could be applicable for searching life in other extreme environments or for the study of extraterrestrial samples (Petit et al, 2005).…”

Section: Surprises From the Deep Icementioning

confidence: 99%

The Vostok Venture: An Outcome of the Antarctic Treaty

Petit¹

2011

Science Diplomacy : Science, Antarctica, and the Governance of International Spaces

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INTRODUCTIONPolar ice sheets and glaciers contain well-ordered archives of ancient ice that fell as snow, years to millions of years ago. With an ice blanket of more than 3 km thick and an annual precipitation rate comparable to that from hyperarid regions (equivalent to 2-5 cm water annually), the slow-moving East Antarctic plateau has considerable potential for providing a long-undisturbed ice sequence. Because of the remoteness of inland sites along with the harsh weather conditions, exploration and deployment of scientific traverses or deep ice core drilling operations require coordination of considerable logistic support, technical, and scientific skills.Vostok station was settled at the time of the International Geophysical Year (IGY) by the Soviet Union and is a location 1,400 km from the coast at 3,488 m above sea level altitude, with an annual temperature of -55°C. Thanks to the Antarctic Treaty, which promoted the international collaboration, the study of a 2-km-deep ice core revealed the close link between temperature and atmospheric CO 2 over the last 150,000 years. This fact soon revealed the climate issues caused by increasing anthropogenic emissions of greenhouse gases.The ice composition and impurities and the gases trapped in air bubbles provide a unique history of the past climate change and environmental and atmospheric composition. By reaching 3.4 km depth, the climate record was extended back 400,000 years, confirming the close climate-greenhouse gas relationship. This link is now further extended over 800,000 years.At the base of the ice sheets the geothermal flux warms the ice, up to the melting point in some places. The water produced accumulates at the interface with the bedrock to form a lake. This is the case in the region of Vostok, where a giant lake lies under the station. Ice core drilling penetrated an ice massif of refrozen lake water at 3.6 km depth. The recovery of frozen lake samples opens new fields for research, especially for the search for life in this very extreme environment, which may help the search for life elsewhere.

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Lake Vostok, Antarctica: Exploring a Subglacial Lake and Searching for Life in an Extreme Environment

Cited by 27 publications

References 88 publications

High-resolution record of Northern Hemisphere climate extending into the last interglacial period

High-resolution record of Northern Hemisphere climate extending into the last interglacial period

Insights into hydrological regime of Lake Vostok from differential behavior of deuterium and oxygen‐18 in accreted ice

The Vostok Venture: An Outcome of the Antarctic Treaty

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