Dynamic flows create potentially habitable conditions in Antarctic subglacial lakes

• Main Authors: Couston, Louis-Alexandre, Siegert, Martin
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: arXiv 2021
• Subjects: Fluid Dynamics physics.flu-dyn; Geophysics physics.geo-ph; FOS Physical sciences; Antarctic; The Antarctic; Antarc*; Ice Sheet
• Online Access: https://dx.doi.org/10.48550/arxiv.2102.10007; https://arxiv.org/abs/2102.10007

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. : This article is published in Science Advances and supplementary material is available at http://advances.sciencemag.org/cgi/content/full/7/8/eabc3972/DC1