Differential analysis of prokaryotic communities from pristine mangrove tidal zone sediments reveal distinct structures and functional profiles

Abstract

<jats:p>Abstract. Mangrove forests are intertidal ecosystems that constitute a large portion of the world's coastline, as such, they are composed of, and reliant upon, microhabitats defined by the tides. However, we are only beginning to understand tidal microhabitat biodiversity and their role in nutrient cycling. The majority of metagenomic studies have so far been conducted on anthropogenically impacted areas. As even mild disruption can severely alter ecosystems and lead to decreased biodiversity and local extinctions, this is a critical issue. Here, we characterize prokaryotic populations and their involvement in nutrient cycling across the tidal zones of a pristine mangrove forest within a Brazilian Environmental Protection Area of the Atlantic Forest. We hypothesize that tidal zones in pristine mangroves constitute distinct microhabitats, are composed of different prokaryotic communities and, consequently, distinct functional profiles. Samples were collected in triplicate from zones below, between, and above the tidal waterline. Using 16S amplicon sequencing, we find significantly different prokaryotic communities with diverse nutrient cycling related functions, as well specific taxa with varying contribution to functional abundances between zones. Our findings contrast those observed in anthropogenically impacted mangroves and suggest that some aspects of mangrove zonation may be compromised by human activity. </jats:p>