AUTHOR=Hollingsworth Anita L. , Jones Daniel O. B. , Young C. Robert TITLE=Spatial Variability of Abyssal Nitrifying Microbes in the North-Eastern Clarion-Clipperton Zone JOURNAL=Frontiers in Marine Science VOLUME=8 YEAR=2021 URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.663420 DOI=10.3389/fmars.2021.663420 ISSN=2296-7745 ABSTRACT=
Abyssal microbes drive biogeochemical cycles, regulate fluxes of energy and contribute to organic carbon production and remineralization. Therefore, characterizing the spatial variability of benthic microbes is important for understanding their roles in benthic environments and for conducting baseline assessments of areas of the seabed that might be targeted by commercial mining activities. Yet, detailed assessments of the spatial distributions of benthic microbial communities in these regions are still incomplete, and these efforts have not yet considered the influence of seafloor topography and heterogeneity on microbial distributions across a range of scales. In this study, we investigated the composition and spatial variability of benthic microbial assemblages found in sediments and polymetallic nodules collected from the Clarion Clipperton Zone (CCZ) in the equatorial Pacific (4000–4300 m water depth). We used 16S rRNA gene sequences to characterize these communities. The upper 20 cm of abyssal sediments harbored diverse and distinctive microbial communities in both sediments and their associated polymetallic nodules, with high similarity across topographical areas of the seabed. Assemblage composition differed vertically through the sediment, by habitat and across small to mesoscales. Potential carbon-fixing microbes formed more than 25% relative abundance of sediment assemblages, which were dominated by ammonia-oxidizing Archaea