Bacteria in Their Natural Habitats

The Spectrum of Organisms Bacteria in Their Natural Habitats 

Attention is directed to organisms that have hitherto evaded isolation or are represented by only a few cultivated examples. Such organisms may well outnumber those that have been isolated as pure cultures, frequently using elective enrichment. A few illustrations are given below  

Archaea belonging to the kingdom Crenarchaeota deserve attention. Although it has been assumed that these are extreme thermophiles, members of this group have been identified by molecular techniques in other habitats, for example, soils (Buckley et al. 1998), boreal forest soil (Jurgens et al. 1997), and in plant extracts (Simon et al. 2005). 

Before discussing some of the larger groups of microorganisms that have been implicated in biodegradation and biotransformation, brief comments are made on other groups of organisms that have hitherto attracted somewhat limited attention  

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Organisms in natural ecosystems may not be actively dividing but may, nonetheless, be metabolically active. This may be particularly important for ultramicro marine bacteria in their natural habitat. 

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