Active bacterial and archaeal communities in coastal sediments: Biogeography pattern, assembly process and co-occurrence relationship

The biogeography of active microbial communities and the underlying mechanisms in marine sediments are important in microbial ecology but remain unclear. Here, using qPCR and high-throughput sequencing, we investigated bacterial and archaeal community abundances and activities by quantifying the abundance and expression of the 16S rRNA gene respectively, RNA-derived bacterial and archaeal community biogeography, assembly mechanisms and co-occurrence relationships in surface sediment samples from the Bohai Sea (BS), South Yellow Sea (SYS) and the north East China Sea (NECS) of the eastern Chinesemarginal seas. The results revealed a higher heterogeneity of bacterial and archaeal community activities than of abundances and heterogeneous ecological functions among areas reflected by community compositions. Furthermore, clear geographic groups (i.e., the BS, SYS and NECS groups) were observed for all, abundant and rare active bacterial and archaeal communities, accompanied by significant distance-decay patterns. However, the abundant and rare taxa showed inconsistent geographic patterns. More importantly, deterministic processes played a greater role than stochastic processes in active bacterial and archaeal community assembly. The rare taxa hadweaker abilities to disperse and/or adapt andmore complex ecological processes than the abundant taxa. In addition, this study also showed that intertaxa competition was the dominant interaction between active bacterial and archaeal members, which could greatly contribute to dispersal limitation. Moreover, active bacterial and archaeal co-occurrence patterns showed significant distance-decay patterns, which were consistent with the community compositions. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The study investigated the biogeography and assembly mechanisms of active bacterial and archaeal communities in marine sediments from the Bohai Sea, South Yellow Sea, and the north East China Sea. It revealed higher heterogeneity in community activities than abundances, with clear geographic patterns and a greater role of deterministic processes in community assembly. Additionally, intertaxa competition was found to be the dominant interaction between active bacterial and archaeal members, contributing to dispersal limitation.