Effects of tidal influence on the structure and function of prokaryotic communities in the sediments of a pristine Brazilian mangrove

Abstract. Mangrove forests are ecosystems that constitute a large portion of the world's coastline and span tidal zones below, between, above waterline, ecosystem as whole is defined by health these microhabitats. However, we only beginning to understand tidal-zone microbial biodiversity role microbiomes in nutrient cycling. While extensive research has characterized pristine vs. anthropogenically impacted mangroves, have, largely, overlooked differences microhabitats (sublittoral, intertidal, supralittoral). Unfortunately, small number studies have sought characterize mangrove occurred biomes, making interpretation results difficult. Here, prokaryotic populations their involvement cycling across within Brazilian Environmental Protection Area Atlantic Forest. We hypothesized mangroves distinct microhabitats, which regions present spatial variations water regime other environmental factors, such, composed different communities with functional profiles. Samples were collected triplicate from waterline. Using 16S ribosomal RNA (rRNA) gene amplicon sequencing, found significantly diverse nutrient-cycling functions, well specific taxa varying contributions abundances between zones. Where previous intertidal zone high diversity be functionally enriched nitrogen cycling, find lowest no enrichment, relative The main bacterial phyla all samples Firmicutes, Proteobacteria, Chloroflexi while archaeal Crenarchaeota Thaumarchaeota. Our differ slightly where Proteobacteria sediments Firmicutes makes up percentage communities. Salinity organic matter most relevant factors influencing Bacillaceae was abundant family at each showed potential drive proportion carbon, nitrogen, phosphorus, sulfur. findings suggest some aspects zonation may compromised human activity, especially zone.