The Bacteriostatic and Bactericidal Action of Great Salt Lake Water

Abstract

Great Salt Lake in northern Utah is an extensive and extremely saline body of water having considerable geological, historical, commercial and biological interest. The water usually con-tains more than 20 per cent salt and in December 1935 when the water for the experiments reported below was collected, the salinity was 27.6 per cent. In reviewing the literature of bac-terial life in strong brines Hof (1935) shows that most species which have been tested tolerate no more than 6 per cent salt and he concludes that 15 per cent salt limits the activities of halo-philes with very few exceptions. Previous to the work of Daines (1917) who recovered as many as 625 bacteria per milliliter of water from Great Salt Lake, it was believed to be sterile. How-ever, inasmuch as he isolated these bacteria on 2.5 per cent NaCl nutrient agar, his investigations failed to show whether the bacteria were halophiles indigenous to the lake or if they were merely halotolerant contaminants. In a survey covering a large number of samples collected during the last year from different depths and stations, Smith (1936) almost invariably found a few hundred bacteria per milliliter of lake water which developed on lake water media. Using a direct microscopic technique Smith and ZoBell (1936) have demonstrated the occurrence of autochthonous bacteria in Great Salt Lake which are capable of multiplying to form micro-colonies on glass slides submerged in the brine. In continuing these studies it is desirable to know if the bacteria found in the