heterotrophic activity can be detected at À20
C within a few days, and photosystem
activity required for photosynthesis can be detected at À20
C as well. Several subzero-growing bacterial, fungal and algal isolates capable of growth at À5
C can be
readily isolated from the sandstone, without the enrichment steps needed for the
University Valley permafrost soils (Goordial et al. 2017).
Cryptoendolithic microbial communities promote bioweathering of the rock and
in some cases cause telltale exfoliation patterns to indicate where life once was
abundant. Oxalic acid produced by the communities dissolves the cementing materials between mineral grains—causing more area to colonize but also overtime
resulting in exfoliation and loss at once of the majority of biomass (Friedmann
Fig. 6.2 (a) Sandstone valley wall in University Valley teeming with hidden life. (b)
Cryptoendolith with ruler (showing cm scale). Black melanized fungi can be seen just beneath
the surface of the rock. (c) Opened cryptoendolithic rocks, with visible life (coloured bands) within
the first few mm of the surface of the rock facing the sun
6 When the Vital Signs of Microbial Life Go Cold, Does That Mean the Pulse Is. . .
123
C within a few days, and photosystem
activity required for photosynthesis can be detected at À20
C as well. Several subzero-growing bacterial, fungal and algal isolates capable of growth at À5
C can be
readily isolated from the sandstone, without the enrichment steps needed for the
University Valley permafrost soils (Goordial et al. 2017).
Cryptoendolithic microbial communities promote bioweathering of the rock and
in some cases cause telltale exfoliation patterns to indicate where life once was
abundant. Oxalic acid produced by the communities dissolves the cementing materials between mineral grains—causing more area to colonize but also overtime
resulting in exfoliation and loss at once of the majority of biomass (Friedmann
Fig. 6.2 (a) Sandstone valley wall in University Valley teeming with hidden life. (b)
Cryptoendolith with ruler (showing cm scale). Black melanized fungi can be seen just beneath
the surface of the rock. (c) Opened cryptoendolithic rocks, with visible life (coloured bands) within
the first few mm of the surface of the rock facing the sun
6 When the Vital Signs of Microbial Life Go Cold, Does That Mean the Pulse Is. . .
123