Halophilic Archaea, Microbiology
editThe Archaea were introduced as a distinct domain besides the Bacteria and Eukarya in the mid-1970s by Carl Woese on the basis of 16s rRNA sequences (Woese and Fox, 1977;Woese et al., 1990). The name Archaebacteria and later Archaea was chosen as the first known members of this domain were found to live under extreme conditions. Such conditions might reflect the environmental situation on earth when life came into existence. By now, cultivation-independent approaches have shown that archaea do not exist exclusively in extreme habitats but are present in almost all environments examined to date (DeLong and Pace, 2001). For example, fluorescent in situ hybridisation experiments revealed that archaea represent 20% or more of all microbial cells in the oceans (DeLong et al., 1999). All members of the Halobacteriaceae are obligate halophiles, that means they need elevated salt concentrations (2M- 5.2M for halobacteria) for growths (Oren, 1994)