Limnological conditions in Subglacial Lake Vostok, Antarctica

Christner, Brent C.; Royston-Bishop, George; Foreman, Christine M.; Arnold, Brianna R.; Tranter, Martyn; Welch, Kathleen A.; Lyons, W. Berry; Tsapin, A. I.; Studinger, M.; Priscu, John C.

doi:10.4319/lo.2006.51.6.2485

Cited by 176 publications

(182 citation statements)

References 62 publications

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“…Surface water from Subglacial Lake Vostok, East Antarctica, which had accreted to the base of the ice sheet, was recovered during drilling of the Vostok ice core [15]. Samples of this material contained microbial cells and offered the first evidence for deep subsurface life in Antarctica [6,16,17]. A sediment core collected from under the Kamb Ice Stream (KIS), West Antarctica, which is due north of Whillans Ice Stream (WIS), was also shown to contain viable microbial cells [18].…”

Section: Antarctic Subglacial Lakes: An Underexplored Microbial Habitatmentioning

confidence: 99%

“…It is now accepted that there are a variety of aqueous features beneath ice sheets including 'wetlands' or saturated sediments, streams, rivers and lakes [3,4]. As of this writing, 379 perennial subglacial lakes have been identified below the Antarctic ice sheets [5] and these lakes likely represent a variety of chemistries ranging from fresh [6,7] to highly saline [8,9]. Subglacial hydrological environments require meltwater, which forms from pressure-induced melting of basal ice or heating from geothermal flux at the bed [10].…”

Section: Antarctic Subglacial Lakes: An Underexplored Microbial Habitatmentioning

confidence: 99%

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Subglacial Lake Whillans microbial biogeochemistry: a synthesis of current knowledge

Mikucki

Lee

Ghosh

et al. 2016

Phil. Trans. R. Soc. A.

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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 cyclingauthorsversionPeer reviewe

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Section: Antarctic Subglacial Lakes: An Underexplored Microbial Habitatmentioning

confidence: 99%

Section: Antarctic Subglacial Lakes: An Underexplored Microbial Habitatmentioning

confidence: 99%

Subglacial Lake Whillans microbial biogeochemistry: a synthesis of current knowledge

Mikucki

Lee

Ghosh

et al. 2016

Phil. Trans. R. Soc. A.

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“…[5] Viable microbes have now been detected in significant concentrations (10 4 -10 7 cells mL À1 ) beneath all types of ice mass, including small valley glaciers [Sharp et al, 1999;Foght et al, 2004], polythermal-based glaciers [Skidmore et al, 2000], ice caps [Gaidos et al, 2004], and the Greenland [Kivimaki, 2004;Christner et al, 2003;Miteva et al, 2004] and Antarctic ice sheets [Mikucki et al, 2004;Christner et al, 2006]. These viable microbes include methanogens, found in basal ice from Greenland (via GISP2 [Tung et al, 2005]) and John Evans Glacier, Canada [Skidmore et al, 2000].…”

Section: Evidence For Methane Production Under Icementioning

confidence: 99%

Subglacial methanogenesis: A potential climatic amplifier?

Wadham

Tranter

Tulaczyk

et al. 2008

Global Biogeochemical Cycles

114

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[1] Subglacial environments are a previously neglected component of the Earth's global carbon cycle, a reflection of the view held until recently that they are dominated by abiotic and oxic conditions. Here we provide a realistic assessment of the theory that the basal regions of the ice sheets that formed over North America and Europe during glaciations were host to significant populations of anaerobic microorganisms, including methanogens, able to metabolize organic carbon sequestered during interglacials and overridden during Quaternary glacials. In doing so, we review the current evidence for subglacial methane release during deglaciation, estimate the size of the subglacial reservoir of organic carbon (SOC), and assess the amount of SOC available to subglacial microbes and the likely pathways and rates of carbon turnover. We then discuss the fate of subglacial methane and the potential impact of its release on atmospheric methane concentrations. We calculate that the SOC equates to 418-610 Pg C and includes carbon from terrestrial soils/vegetation, peatlands, lake, and marine sediments. The SOC that is potentially available for microbial conversion to methane is smaller than this estimate due to (1) glacial erosion, (2) accumulation of recalcitrant organic carbon compounds over time, (3) conversion to carbon dioxide by aerobic/anaerobic respiration, and (4) incomplete conversion of labile organic matter to methane. We estimate that the total SOC available for conversion to methane is 63 Pg C. Our estimates of methane production potentials span a wide range because of the current uncertainty surrounding subglacial metabolic rates. We believe, however, that there is a strong likelihood that subglacial microbes could convert 63 Pg of SOC to methane during a glacial cycle. If this were the case, release of this methane from the ice sheet margins during retreat would need to be episodic in order to significantly impact atmospheric methane concentrations. Our findings suggest that it may well be important to consider subglacial environments as active components of the Earth's carbon cycle. Conclusive determination of the potential impact of subglacial methane production on atmospheric methane concentrations during deglaciation, however, awaits more precise determination of the ability of subglacial microbes to degrade organic carbon components and their associated rates of metabolism under in situ conditions.

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“…The presence of a sustained microbial ecosystem in the subglacial environment is hypothesized, based on the analysis of accreted ice recovered from Lake Vostok's ice core. In this core higher concentrations of microbial remnants compared to the meteoric ice have been identified, indicating the potential existence of life forms in the lake, as was speculated over a long period of time (Souchez et al, 2003;Christner et al, 2006). Due to obvious difficulties with exploration of subglacial lakes, numerical modelling remains an important tool to examine internal processes, such as the water circulation or melting and freezing processes at the ice-water interface.…”

Section: Introductionmentioning

confidence: 99%

Modelling flow and accreted ice in subglacial Lake Concordia, Antarctica

Thoma

Grosfeld

Filina

et al. 2009

Earth and Planetary Science Letters

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More than 150 subglacial lakes have been discovered in Antarctica so far. Due to obvious challenges with exploration, numerical modelling remains one of the major tools to acquire information about those hard-to-access objects. Until now only the huge Lake Vostok has been investigated in detail. This paper focuses on Lake Concordia -the second largest subglacial lake in Antarctica over which substantial geophysical data has been collected. This lake is covered by about 4000 m ice and is located near Dome C. In order to apply numerical models to the hard-to-access Antarctic subglacial lakes, decent geometries and boundary conditions are required. In this study we present the results of airborne gravity inversion, suggesting that this lake has an area of 617 km 2 , a volume of 31 km 3 , and a maximum water column thickness of 126 m. This bathymetry is used as geometry input for an established 3D-numerical lake-flow model to simulate the circulation and basal mass balance. Compared to our model studies of subglacial Lake Vostok, we obtain a general circulation pattern that is significantly weaker (due to the smaller size of the lake) and of reversed orientation (due to the reversed ice surface tilt). The modelled mean horizontal and vertical velocities are in the order of 0.2 mm/s and 0.5 µm/s, respectively. The larger molecular convective velocity estimations (1.35 ± 0.13 mm/s and 0.81 ± 0.08 mm/s) are similar to Lake Vostok's. The modelled average melting and freezing rates are 4.3±1.1 mm/a and 1.1±0.3 mm/a, respectively, and the corresponding fresh water gain is 58±27 dm 3 /s. Integration of the modelled freezing and melting along prescribed ice flow lines allows us to calculate the distribution and thickness of accreted ice at the ice sheet bottom. We estimate a volume of 2.6±2.0 km 3 (8.3 ± 8.2% of the total lake volume) occupying the north-eastern corner of the lake covering an area of 159±48 km 2 (26 ± 9% of the total lake area). With about 16 800±7 600 years, the residence time of the lake's water is significantly shorter than Lake Vostok's.

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Limnological conditions in Subglacial Lake Vostok, Antarctica

Cited by 176 publications

References 62 publications

Subglacial Lake Whillans microbial biogeochemistry: a synthesis of current knowledge

Subglacial Lake Whillans microbial biogeochemistry: a synthesis of current knowledge

Subglacial methanogenesis: A potential climatic amplifier?

Modelling flow and accreted ice in subglacial Lake Concordia, Antarctica

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