Subglacial lakes

Siegert. M.J. Ellis-Evans. J.C. Tranter, M. Mayer, C. Petit. J.-R. Salamatin, A. Priscu. J.C. Physical, chemical and biological processes in Lake Vostok and other antarctic subglacial lakes. Nature 2001. 414. 603-609. 

The present elevation of the bedrock surface of some parts of East and West Antarctica is actually below sea level. Eor example, two large subglacial basins in Wilkes Land of East Antarctica lie below sea level. In addition, the surface of subglacial Lake Vostok at 78°28 S and 106°48 E is below sea level by about 200-300 m. The bedrock surface of most of West Antarctica is also below sea level partly because of the mass of the overlying ice sheet (Drewry et al. 1983 Bentley and Robertson 1982 Bentley et al. 1982). Consequently, the incursion of seawater into the subglacial basins could result in the hreak-np of the West Antarctic ice sheet and of the ice in the Wilkes basin of East Antarctica. 

Fig. 17.35 Lake Vostok in East Antarctica is the largest of about 160 subglacial lakes that have been discovered by radar echo surveys. The lake is about 300 km long and about 50 km wide. It is covered by 3,700 m of ice and occupies a tectonic rift that is bounded by deep faults. Lake Vostok was named after the Russian research station that is located close to the southern end of the subglacial lake. Lake Sovetskaya and 90°E Lake, which are located close to the 90°E Meridian may also occupy rift basins (Adapted from MODIS Mosaic of Antarctica acquired by NASA s satellites Terra and Aqua between November 20, 2003 and February 29,2004)...

Bell RE, Studinger M, Fahnestock MA, Shuman CA (2006) Tectonically controlled subglacial lakes on the flanks of the Gamburtsev subglacial mountains. East Antarctica. Geophys Res Lett 33 LO2504, 4p... 

The subglacial lake is sealed off from the air, so the oxygen must come from a solid or liquid source. These bacteria eat sulfate, pulling one of the four oxygens off it and producing the three-oxygen chemical sulfite. These bacteria reduce sulfate because this process takes oxygen away from it, the opposite of oxidation. Sulfate... 

A group of Russian scientists carefully drilled into it... Y. M. Shtarkman et aL Subglacial Lake Vostok (Antarctica) accretion ice contains a diverse set of sequences from aquatic, marine and sediment-inhabiting bacteria and eukarya. 2013. PLoS One 8(7), p. e67221. DOl 10.1371/journal.pone.0067221. 

Such a mission would require successful drilling through the moon s surface ice layer (Rummel, 2000 de Morais, 2000) testing of a new apparatus required for the study of Europa s ice could be done in the subglacial Antarctic Lake Vostok, under the Antarctic ice. It does not, however, seem appropriate to test such technologies in this extremely sensitive environmental situation. However, Russian scientists are carrying out drilling studies on Lake Vostok (Inman, 2006). 

Priscu JC et al. (11) (1999) Geomicrobiology of subglacial ice above Lake Vostok, Antarctica. Science 286 2141-2144... 

Jouzel J., Petit J. R., Souchez R., Barkov N. 1., Fipenkov V. Y., Raynaud D., Stievenard M., Vassiliev N. 1., Verbeke V., and Vimeux F. (1999) More than 200 m thick of lake ice above the subglacial Fake Vostok, Antarctica. Science 2138-2141. 

It has been inferred that the waters of Lake Vostok and numerous other subglacial Antarctic lakes contain oxygen sufficient to support life in an unique ecosystem, at 350 atm and — 3°C. in permanent darkness. Though the lake water has not been sampled for fear of introducing bacteria from above, oxygen is found in the refrozen lake water just above the lake. The oxygen comes from the decomposition of air hydrates present in the ice overburden. 

Large meltwater lakes that exist at the base of the East Antarctic ice sheet may be linked by subglacial streams of liquid water. 

Fig. 17. 36 The East Antarctic ice sheet loses mass not only by melting of basal ice, but also by means of ice streams and outlet glaciers. For example, the Recovery ice streams which are lubricated by water that originates from the subglacial Recovery lakes transports ice to the Filchner Ice Shelf, whereas the outlet glaciers which cross the Transantarctic Mountains discharge ice into the Ross Ice Shelf and directly into the Ross Sea. Similarly, ice streams that drain the West Antarctic ice sheet contribute most of the ice into the Ross Ice Shelf (Adapted from Bindschadler and Bentley 2002. By permission of the authors and the Editor of Scientific American)...

The distribution of the coUecting sites along the eastern margin of the Lewis CUff ice tongue and within the adjacent ice-cored moraine ridges indicates that the minerals formed both by evaporation of brines that were extruded through near-vertical fractures in the ice as well as by subglacial precipitation. The salt deposits that occur in the soil of the ice-free vaUeys and associated with saline lakes and ponds in this area are presented in Chapter 19. 

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