  Trapped beneath the Antarctic ice sheet lie over 400 subglacial lakes, which
are considered to be extreme, isolated, yet viable habitats for microbial life.
The physical conditions within subglacial lakes are critical to evaluating how
and where life may best exist. Here, we propose that Earth's geothermal flux
provides efficient stirring of Antarctic subglacial lake water. We demonstrate
that most lakes are in a regime of vigorous turbulent vertical convection,
enabling suspension of spherical particulates with diameters up to 36
micrometers. Thus, dynamic conditions support efficient mixing of nutrient- and
oxygen-enriched meltwater derived from the overlying ice, which is essential
for biome support within the water column. We caution that accreted ice
analysis cannot always be used as a proxy for water sampling of lakes beneath a
thin (<3.166 kilometers) ice cover, because a stable layer isolates the
well-mixed bulk water from the ice-water interface where freezing may occur.
