PRJNA665104
Bacterial/archaeal 16S associated with sub-bottom reef sediment
Despite being key components of biogeochemical cycling on tropical reefs, comparatively little is known about the microbial communities in deeper sediment assemblages (>1 m) below the reef benthos, especially with regards to their roles in mineralisation of organic matter and export of limiting nutrients such as nitrogen into the surrounding oligotrophic waters. Here, using 16S rRNA metabarcoding and predictive functional analysis, we present the first characterisation of microbial community structure and putative nitrogen cycling pathways in radiocarbon-dated sub-bottom sediment of up to 3.5 m beneath the reef substrate. The data suggest that sub-bottom community composition may be influenced by bioturbation, with several microbial taxa documented for the first time in this habitat that may contribute to novel ecosystem functions. The functional predictions reveal sediment microbial involvement in all major pathways of the nitrogen cycle. Coral cover was not significant in explaining the community structure of KEGG orthologs associated with microbial nitrogen metabolism, while landfill proximity significantly structured the KEGG orthologs linked to pathways which involve ammonium or nitrate as a reactant