Bacterial Communities in Polluted Seabed Sediments: A Molecular Biology Assay in Leghorn Harbor

Abstract

Seabed sediments of commercial ports are often characterized by high pollution levels. Differences in number and distribution of bacteria in such areas can be related to distribution of pollutants in the port and to sediment conditions. In this study, the bacterial communities of five sites from Leghorn Harbor seabed were characterized, and the main bacterial groups were identified. T-RFLP was used for all samples; two 16S rRNA libraries and in silico digestion of clones were used to identify fingerprint profiles. Library data, phylogenetic analysis, and T-RFLP coupled with in silico digestion of the obtained sequences evidenced the dominance of Proteobacteria and the high percentage of Bacteroidetes in all sites. The approach highlighted similar bacterial communities between samples coming from the five sites, suggesting a modest differentiation among bacterial communities of different harbor seabed sediments and hence the capacity of bacterial communities to adapt to different levels and types of pollution.

The metabolic core of the prokaryotic community from deep-sea sediments of the southern Gulf of Mexico shows different functional signatures between the continental slope and abyssal plain

“…Rare taxa affiliated to some of the groups identified in this study i.e. , Chlorobi, Deinococcus-Thermus, Elusimicrobia, Gemmatimonadetes, Lentisphaerae, Spirochaetes and Tenericutes, have also been identified in low abundance in sediments from different aquatic environments, particularly associated with the oxic-anoxic transition in the environment ( Chiellini et al, 2013 ; Liu et al, 2015 ; Martino et al, 2019 ; Oni et al, 2015 ; Rissanen et al, 2019 ).…”

Biological Responses at Supraindividual Levels

“…Although in other biotic components, the measures of diversity are mainly based on taxonomic composition, in the bacterial and archaeal ones, the measures are usually based on molecular operational taxonomic units. Research carried out in a polluted harbor by Iannelli et al (2012) and Chiellini et al (2013) found that diversity did not diverge significantly among samples with differing pollution levels, and research on the impact of aquaculture (Bissett et al, 2007;Castine et al, 2009;Kawahara et al, 2009) found that sedimentary bacterial communities may change under the organic perturbations, but that does not necessarily translate to a clear change in diversity. However, the situation, like that of the macrobenthic communities, is complicated and unclear, with previous studies by Ellis et al (2003) and Gillan et al (2005) suggesting that bacterial diversity is not related to long-term metal pollution.…”

Bacterial Community Characterization in Paper Mill White Water

“…Chimeric sequences were analyzed by cutting them in proximity of the supposed recombination site and treating them as separate sequences according to Chiellini et al (2013c).…”