  Microbes are often discussed in terms of dichotomies such as
copiotrophic/oligotrophic and fast/slow-growing microbes, defined using the
characterisation of microbial growth in isolated cultures. The dichotomies are
usually qualitative and/or study-specific, sometimes precluding clear-cut
results interpretation. We are able to interpret microbial dichotomies as life
history strategies by combining ecology theory with Monod curves, a classical
laboratory tool of bacterial physiology. Monod curves relate the specific
growth rate of a microbe with the concentration of a limiting nutrient, and
provide quantities that directly correspond to key ecological parameters in
McArthur and Wilsons r/K selection theory, Tilmans resource competition and
community structure theory and Grimes triangle of life strategies. The
resulting model allows us to reconcile the copiotrophic/oligotrophic and
fast/slow-growing dichotomies as different subsamples of a life history
strategy triangle that also includes r/K strategists. We analyzed some
ecological context by considering the known viable carbon sources for
heterotrophic microbes in the framework of community structure theory. This
partly explains the microbial diversity observed using metagenomics. In sum,
ecology theory in combination with Monod curves can be a unifying quantitative
framework for the study of natural microbial communities, calling for the
integration of modern laboratory and field experiments.
