Geoscience Reference
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Fig. 2.16 In Schirmacher oasis, Dronning Maud Land, Antarctica there are lakes where lake ice
may survive over summer. The picture shows such lake at the Russian Novolazarevskaya Station
(70 ° 49.3 S11 ° 38.7 E) in late summer, February 4, 2005
at about - 2.5 ° C. The water body must be in balance between the geothermal heat flux
from the ground and conduction of heat through the overlaying ice sheet. The largest
subglacial lake is Lake Vostok, located close to the Russian Vostok station.
Supraglacial lakes form and grow from the penetration of solar radiation into the ice
sheet. For suf
cient penetration, the surface needs to be ice and therefore these lakes form
in glacial blue ice regions. The depth of seasonal supraglacial lakes is of the order of 1 m.
When the surface heat balance is negative, the lake has an ice cover. They are extremely
low in biota (Keskitalo et al. 2013). Supraglacial lakes are found on the Antarctic and
Greenland ice sheets and in many mountain glaciers. In Greenland they are much more
developed and have a major impact on the ice mass balance (Hoffman et al. 2011; Liang
et al. 2012). If a supraglacial lake can preserve some of its water in liquid state over the
winter, it starts a year-by-year growing stage. This would accelerate local melting, lead to
lake growth and eventually catastrophic formation of fractures taking the water in and
ending in a major change in the local glacial environment.
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