Isolation of psychrophilic halophiles from the Antarctic polar desert

Abstract

Saline soils in the Dry Valley region of McMurdo Sound, Antarctica, contained bacteria showing salt tolerance or requirement. Soils were plated by the spread plate method on soil extract-peptone-yeast extract media to which sodium chloride had been added in concentrations from 0 to15 per cent (w/v). Bacteria isolated from these media at 2 °C, 5 °C, and 15 °C were predominantly Gram negative rods with few Gram positive rods and cocci. No filamentous fungi or Halobacterium spp. were observed on the media used. At 15 C there were no isolates from media containing greater than 15 percent added salt; however, counts of 1.4 x 10³ colonies per gram of soil were found at this concentration. As the incubation temperatures were lowered, salt tolerance was lowered. The data indicate that the limited soil microflora observed in saline soils and ponds may be attributed to a combination of low maximal summer temperature and high salinity.