Bacterial community diversity and dynamics of Dongzhai harbor mangrove soils in China

Dongzhai Harbor National Nature Reserve is the largest mangrove reserve in China, but the bacterial diversity and community structure of soils in the Dongzhai harbor mangrove (DHM) is still not well known. This study was conducted to characterize and compare the bacterial community diversity and composition of DHM soils in three typical sites (YA, entrance of wastewater and sanitary sewage; YB, located in Dongzhai Harbor National Nature Reserve; YC, near the sea) using high-throughput sequencing of the 16S rDNA. Community statistical analyses suggested that the YB and YC soils have a similar community structure, but they differ from the YA soils significantly. Proteobacteria and Chloroflexi were the ubiquitous and dominant groups that made up nearly 80% of total bacterial communities, but it was noted that Chloroflexi had a higher relative abundance in YA soil samples than YB and YC soil samples and that the operational taxonomic units (OTUs) of Anaerolineaceae, Gammaproteobacteria, and Thiogranum reached extremely significant levels. Interaction network analysis of the 50 most abundant OTUs further demonstrated that the OTUs of YA showed few interactions with YB and YC OTUs, and the Cluster of Orthologous Group (COG) involved in lipid transport and metabolism showed significant differences between the YA and YB soil samples. Our results will greatly help to understand the bacterial community variation of the DHM as human activities enhance and grow, and to identify some challenges for the restoration and management of the mangrove ecosystem.