Patterns of benthic bacterial diversity in coastal areas contaminated by heavy metals, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs)

Abstract

Prokaryotes in coastal sediments are fundamental players in the ecosystem functioning and regulate processes relevant in the global biogeochemical cycles. Nevertheless, knowledge on benthic microbial diversity patterns across spatial scales, or as function to anthropogenic influence, is still limited. We investigated the microbial diversity in two of the most chemically polluted sites along the coast of Italy. One site is the Po River Prodelta (Northern Adriatic Sea), which receives contaminant discharge from one of the largest rivers in Europe. The other site, the Mar Piccolo of Taranto (Ionian Sea), is a chronically polluted area due to steel production plants, oil refineries, and intense maritime traffic. We collected sediments from 30 stations along gradients of contamination, and studied prokaryotic diversity using Illumina sequencing of amplicons of a 16S rDNA gene fragment. The main sediment variables and the concentration of eleven metals, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were measured. Chemical analyses confirmed the high contamination in both sites, with concentrations of PCBs particularly high and often exceeding the sediment guidelines. The analysis of more than 3 millions 16S rDNA sequences showed that richness decreased with higher contamination levels. Multivariate analyses showed that contaminants significantly shaped community composition. Assemblages differed significantly between the two sites, but showed wide within-site variations related with spatial gradients in the chemical contamination, and the presence of a core set of OTUs shared by the two geographically distant sites. A larger importance of PCBdegrading taxa was observed in the Mar Piccolo, suggesting their potential selection in this historically polluted site. Our results indicate that sediment contamination by multiple contaminants significantly alter benthic prokaryotic diversity in coastal areas, and suggests considering the potential contribution of the resident microbes to contaminant bioremediation actions.

Regional variations in the diversity and predicted metabolic potential of benthic prokaryotes in coastal northern Zhejiang, East China Sea

“…However, a number of sulfur-oxidizing species such as Sulfuricurvum kujiense, Sulfurimonas autotrophica , and Sulfurovum lithotrophicum , classified within this family, have been isolated from sulfur-rich environments including freshwater nature reserves, hydrothermal vents, and deep-sea sediments58. Helicobacteraceae were also reported as dominant members in coastal sediments contaminated by organic contaminants7. The high AVS concentration and great relative abundances of bacterial groups with potential members relevant with sulfur metabolism suggested that the Yushan area might be suitable for studying the microbial-mediated processes of sulfur metabolism in coastal sediments.…”

“…Benthic prokaryotes play crucial roles in biogeochemical cycling within marine ecosystems123. The diversity of benthic prokaryotes has been investigated across various coastal marine ecosystems456789, demonstrating a wide range of environmental drivers shaping benthic prokaryotic communities such as sediment depth10, water depth11, temperature12, ocean currents5, sediment texture8, salinity6, nutrients13, organic matter quantity and availability14, heavy metals and organic pollutants7. Previous studies have suggested that geographic distance also drives variation in benthic prokaryotic communities1516.…”

Rhodobacterales and Rhizobiales Are Associated With Stony Coral Tissue Loss Disease and Its Suspected Sources of Transmission

“…The marker size represents the relative abundance of each ASV (scale provided) and bacterial families are represented by different colors. each zone (Martiny et al, 2015;Quero et al, 2015). Microbial signatures are routinely used to identify poor environmental conditions for recreational water use (Fong et al, 2005) and, more recently, studies have shown that microbial markers are also indicators of reef health (Glasl et al, 2017(Glasl et al, , 2019.…”

Metagenomics as a preliminary screen for antimicrobial bioprospecting

“…contamination, located along the coast of Italy at the Po River Prodelta (Northern Adriatic Sea) and the Mar Piccolo of Taranto (Ionian Sea)(Quero et al, 2015). There, results revealed that the core microbiome include Clostridia, Cytophagia, Flavobacteria,Archaea (within the classes Methanobacteria and Methanomicrobia) and several classes within the phylum Proteobacteria.…”