Abstract

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.