微生物地理学

lmz84828

Biogeography is the study of the distribution of biodiversity
often involved in intimate associations that affect each
11,12
. Therefore, a logical
over space and time. It aims to reveal where organisms
other’s geographic distributions
first hypothesis is that the biogeography of microorgan-
live, at what abundance, and why. The study of biogeog-
isms is similar to the biogeography of macroorganisms.
raphy offers insights into the mechanisms that generate
To the extent that microorganisms conform to the rela-
and maintain diversity, such as speciation, extinction,
1
. Since the eighteenth
tionships documented for macroorganisms, they will
dispersal and species interactions
century, biologists have investigated the geographic dis-
extend the generality of empirical patterns and support
tribution of plant and animal diversity. More recently, the
mechanistic hypotheses that all living entities share uni-
geographic distributions of microorganisms have been
versal attributes. Alternatively, if microorganisms can be
examined. Genetic methodologies have revealed that past
shown to represent clear exceptions to the biogeographic
2–4
,
culture-based studies missed most microbial diversity
patterns of plants and animals, then this will call attention
and have allowed recent studies to sample microbial diver-
to unique features of microbial life that have influenced
5,6
sity more deeply and widely than ever before
. Microbial
the generation and maintenance of its diversity.
biogeography stands to benefit tremendously from these
As an initial step towards distinguishing between
advances, although there is still debate as to whether
these hypotheses, we suggest a framework for inves-
7–10
.
microorganisms exhibit any biogeographic patterns
tigating whether microbial assemblages differ in
Although traditionally confined to separate academic
different places and the extent to which this spatial
disciplines, ecologists who study microorganisms and
variation is due to contemporary environmental fac-
those who study macroorganisms have been interacting
tors and historical contingencies. We then discuss the
more often in recent years. Indeed, this article is a result
mechanistic processes that generate and maintain bio-
of a National Center for Ecological Analysis and Synthesis
geographic patterns in macroorganisms and consider
*Department of Ecology
NCEAS) working group composed of scientists from
(
their relevance to microbial biogeography.
and Evolutionary Biology,
both specialties. Our goal here is to review what is known
There is no universal definition of a ‘micro organism’.
80 Waterman Street,
regarding the biogeography of microorganisms in light
The term generally denotes members of the domains
BOX G-W, Brown University,
Providence, Rhode Island
of that of macroorganisms. This inquiry is not driven by
Bacteria and Archaea, as well as microscopic mem-
02912, USA.
the expectation that microorganisms simply follow the
bers of the domain Eukarya (for example, unicellular
Correspondence to J.B.H.M.
patterns of macroorganisms, but rather by the fact that
algae, some fungi and protists). For convenience, we
e-mail: jennifer_martiny
the biogeography of macroorganisms is much better
further define a microorganism as having a mass
@brown.edu
–5
doi:10.1038/nrmicro1341
g and a length of less than 500 μm.
studied. Furthermore, micro- and macroorganisms are
of less than 10