DISTRIBUTION AND DIVERSITY OF HALOPHILIC BACTERIA IN A SUBSURFACE SALT FORMATION

Citation
Rh. Vreeland et al., DISTRIBUTION AND DIVERSITY OF HALOPHILIC BACTERIA IN A SUBSURFACE SALT FORMATION, Extremophiles, 2(3), 1998, pp. 321-331
Citations number
43
Categorie Soggetti
Microbiology,Biology
Journal title
ISSN journal
14310651
Volume
2
Issue
3
Year of publication
1998
Pages
321 - 331
Database
ISI
SICI code
1431-0651(1998)2:3<321:DADOHB>2.0.ZU;2-6
Abstract
The Waste Isolation Pilot Plant (WIPP) is a salt mine constructed 650 meters below the ground surface by the United States Department of Ene rgy. The facility will be used for permanent disposal of transuranic w astes. This underground repository has been constructed in the geologi cally stable Permian age Salado salt formation. Of the wastes to be pl aced into the facility, 85% will be biodegradable cellulose. A 3-year survey of the bacterial populations existing within the facility was c onducted. Bacterial populations were found to be heterogeneously distr ibuted throughout the mine. Populations in some mine areas reached as high as 1.0 x 10(4) colony-forming units per gram of NaCl. The heterog eneous distribution of bacteria within the mine did not follow any rec ognizable pattern related to either age of the workings or to human ac tivity. A biochemical comparison between ten known species of halophil ic bacteria, and strains isolated from both the mine and nearby surfac e hypersaline lakes, showed the presence of extreme halophiles with wi de biochemical diversity, some of which could prove to represent previ ously undescribed groups. The halophilic bacteria isolated from the mi ne were found to degrade cellulose and a wide variety of other carbon compounds. When exposed to two types of common laboratory paper, the c ellulose-degrading halophiles attached to the substrate within 30 minu tes of inoculation. Cultures enriched directly from a brine seep in th e mine easily destroyed both papers and produced detectable amounts of oxalacetic and pyruvic acids. The combination of heterogeneity in the distribution of organisms, the presence of a physiologically diverse community, and the relatively slow metabolism of cellulose may explain several long-standing debates about the existence of microorganisms i n ancient underground salt formations.