Changes of benthic bacteria and meiofauna assemblages during bio-treatments of anthracene-contaminated sediments from Bizerta lagoon (Tunisia)

Abstract

Sediments from Bizerta lagoon were used in an experimental microcosm setup involving three scenarios for the bioremediation of anthracene-polluted sediments, namely bioaugmentation, biostimulation, and a combination of both bioaugmentation and biostimulation. In order to investigate the effect of the biotreatments on the benthic biosphere, 16S rRNA gene-based T-RFLP bacterial community structure and the abundance and diversity of the meiofauna were determined throughout the experiment period. Addition of fresh anthracene drastically reduced the benthic bacterial and meiofaunal abundances. The treatment combining biostimulation and bioaugmentation was most efficient in eliminating anthracene, resulting in a less toxic sedimentary environment, which restored meiofaunal abundance and diversity. Furthermore, canonical correspondence analysis showed that the biostimulation treatment promoted a bacterial community favorable to the development of nematodes while the treatment combining biostimulation and bioaugmentation resulted in a bacterial community that advantaged the development of the other meiofauna taxa (copepods, oligochaetes, polychaetes, and other) restoring thus the meiofaunal structure. The results highlight the importance to take into account the bacteria/meiofauna interactions during the implementation of bioremediation treatment.

Chemical multi-contamination drives benthic prokaryotic diversity in the anthropized Toulon Bay

“…This striking relation tends to contradict the global erosion of marine biodiversity caused by anthropogenic inputs in the marine environment (Johnston and Roberts, 2009). However, the responses of microbial diversity to contaminants are more complex than those of marine macrobiota and similar observations have been reported in other marine coastal sediments (Duran et al, 2015;Li et al, 2013;Paissé et al, 2008).…”

“…Berdjeb et al, 2011;Salcher, 2013;Van Wambeke et al, 2009) or on the influence of chemical pollutants through ecotoxicological approaches (e.g. Besaury et al, 2014;Duran et al, 2015;Kostka et al, 2011;Paisse et al, 2011;Quillet et al, 2012;Rasmussen and Sorensen, 2001). In this study, we chose to investigate the influence of the abiotic environment as a whole on microbial communities by considering together both potentially toxic contaminants and natural substances from various origins.…”

“…Thus, a significant part of this variability remained statistically unexplained in our study, corresponding to some abrupt shifts that were observed in close and chemically similar sampling sites. This could be partly due to biotic factors, such as predation or viral lysis pressures, which are well known for their influence on prokaryotic community abundance and structure (Ben Said et al, 2015;Louati et al, 2013;Ram et al, 2014;Sauret et al, 2015) but…”

Role of environmental factors and microorganisms in determining the fate of polycyclic aromatic hydrocarbons in the marine environment

“…2013a,b; Ben Said et al. 2015). Meio- and macrofauna influence the microbial assemblages, directly as the main predators and indirectly by modifying the environmental conditions.…”

Pesticides in Ichkeul Lake–Bizerta Lagoon Watershed in Tunisia: use, occurrence, and effects on bacteria and free-living marine nematodes

“…3 Average densities of nematodes (individuals/10 cm 2 ) in the different sites from the complex Ichkeul Lake-Bizerta Lagoon. The error bar corresponds to the standard deviation communities (Fleeger et al 2003) through the microbial activity as demonstrated recently (Ben Said et al 2015). Also, the presence of contaminant may change the behavior of macrofauna modifying the predation/grazing rate that, in turn, alters species abundances and community composition (Fleeger et al 2003).…”