permafrost

noun

1. (countable, uncountable)Permanently frozen ground, or a specific layer thereof.

   “Nevertheless, the water molecule is present, as ice, in a solid form in frozen soils or permafrosts, which cover large regions characterised by a polar climate.”

   “In agreement with our overall trends within the permafrost samples, lower nirK and nirS and higher nosZ diversity have been identified in cryoturbated peat vs. unturbated peat soils (Palmer and Horn, 2012 ).”