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ABSTRACT We report the genomic sequences of 14 bacterial isolates from a supraglacial stream on the Cotton Glacier, Antarctica. Fine sediments in the streambed provide habitat for bacterial growth and biofilm formation. The stream represents a natural laboratory for studying the evolution and adaptation of microbes to a humic-free environment. 

ABSTRACT Inland meltwater ponds are common throughout the dry valley region of Antarctica, with seasonal meltwater inputs driving their biogeochemistry. Here, we report the genomic sequences of eight environmental bacterial isolates covering three major phyla from Marr Pond, Taylor Valley, Antarctica. 

ABSTRACT Sediments in cryoconite holes and meltwater streams in the McMurdo Dry Valleys, Antarctica, provide both substrates and conditions that support life in an arid polar desert. Here, we report the genomic sequences of eight environmental, bacterial isolates from Canada Glacier cryoconite holes and stream. These isolates span three major phyla. 

During the growth of a polycrystalline ice lattice, microorganisms partition into veins, forming an ice vein network highly concentrated in salts and microbial cells. We used microfabricated electrochemical impedance spectroscopy (EIS) sensors to determine the effect of microorganisms on the electrochemical properties of ice. Solutions analyzed consisted of a 176μS cm⁻¹conductivity solution, fluorescent beads, andEscherichia coliHB101-GFP to model biotic organisms. Impedance spectroscopy data were collected at −10 °C, −20 °C, and −25 °C within either ice veins or ice grains (i.e., no veins) spanning the sensors. After freezing, the fluorescent beads andE. coliwere partitioned into the ice veins. The corresponding impedance data were discernibly different in the presence of ice veins and microbial impurities. The presence of microbial cells in ice veins was evident by decreased electrical characteristics (electrode polarization between electrode and ice matrix) relative to solid ice grains. Further, this electrochemical behavior was reversed in all bead-doped solutions, indicating that microbial processes influence sensor response. Linear mixed-effects models empirically corroborated the differences in polarization associated with the presence and absence of microbial cells in ice. We show that EIS has the potential to detect microbes in ice and differentiate between veins and solid grains.