The value of studies of monotypic populations is constantly argued in
bacterial ecology. The controversy itself is evidenceofthe strong
awareness that bacterial activities in natural sites are not determined
by the bacteria alone. At the same time, the best evidence that bacteria
are influenced by environmental factors is the contrast between their
behavior in laboratory cultures and their relatively subdued influence
when in the presence of com- petitors, predators, and fluctuating-often
stressful-environmental conditions. Monotypic populations are admittedly
reductionist, but are not therefore irrelevant to bacterial ecology.
Quite the contrary. Without pure culture studies, our understanding of
important and applicable bacterial activities-N fixation, for
example-would still be z limited to what we could discern from a
comparison of events in steamed vis-a-vis un- heated soil. As was
evident throughout the previous volume in this treatise, practically any
method of studying natural bacterial communities upsets them while
permitting only limited assessment of the respective qualities and
quantitative contributions to total com- munity activity of each type of
bacterium present. Total activity itself is difficult to assess and is
not dependably accomplished by any single method. This third volume
comprises information regarding the properties of bacteria as they have
been learned largely from pure culture studies. Its purpose is twofold:
to provide readers with fundamental information regarding the cellular
organization, physiological capabilities, and genetic systems of
bacteria; and to connect known bacterial properties with environmental
influences on them and with their influences on natural processes.
