Revealing the ecological mechanisms driving the diversity patterns
followed by microbial communities across space and through time is an
essential issue in microbial community ecology. In this study, two
typical spatial scaling patterns, including diversity-area and
distance-decay relationships, were investigated for microbial
communities in an ocean sediment ecosystem. Strong spatial scaling
patterns were observed at the whole community level and for the rare
subcommunities, but hardly for the abundant subcommunities. Rare
subcommunities were mainly responsible for the observed spatial scaling
patterns, as also confirmed by extending spatial scaling diversity
metrics to Hill numbers. Distinct ecological mechanisms underlay the
differed spatial scaling patterns followed by abundant and rare
subcommunities. Both environmental heterogeneity and local community
assembly mechanisms drove the microbial spatial scaling patterns.
Environmental heterogeneity was significantly associated with the
spatial scaling metrics of rare but not abundant subcommunities. Strong
ecological drift and dispersal limitation underlay the spatial scaling
patterns of rare subcommunities, whereas high homogeneous selection
weakened the spatial scaling patterns of abundant subcommunities. Such
differed mechanisms driving the spatial scaling patterns of abundant and
rare subcommunities were also experimentally confirmed by deep
sequencing experiments. This study links microbial spatial scaling
patterns with ecological mechanisms, providing novel mechanistic
insights into the diversity patterns followed by different types of
microbes.