Article

Response of sulfate-reducing bacteria to an artificial oil-spill in a coastal marine sediment.

Institut Mediterrani d'Estudis Avançats (IMEDEA-UIB), E-07190, Esporles, Spain.
Environmental Microbiology (Impact Factor: 6.24). 03/2011; 13(6):1488-99. DOI: 10.1111/j.1462-2920.2011.02451.x
Source: PubMed

ABSTRACT In situ mesocosm experiments using a calcareous sand flat from a coastal area of the island of Mallorca in the Mediterranean Sea were performed in order to study the response of sulfate-reducing bacteria (SRB) to controlled crude oil contamination, or heavy contamination with naphthalene. Changes in the microbial community caused by the contamination were monitored by a combination of comparative sequence analysis of 16S rRNA genes, fluorescence in situ hybridization, cultivation approaches and metabolic activity rates. Our results showed that crude oil and naphthalene negatively influenced the total microbial community as the natural increase in cell numbers due to the seasonal dynamics was attenuated. However, both contaminants enhanced the sulfate reduction rates, as well as the culturability of SRB. Our results suggested the presence of autochthonous deltaproteobacterial SRBs that were able to degrade crude oil or polycyclic aromatic hydrocarbons such as naphthalene in anaerobic sediment layers.

0 Bookmarks
 · 
262 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: DNA stable isotope probing and metagenomic sequencing were used to assess the metabolic potential of iron-reducing bacteria involved in anaerobic aromatic hydrocarbon degradation in oil spill-affected tidal flats. In a microcosm experiment, (13) C-toluene was degraded with the simultaneous reduction of Fe(III)-NTA, which was also verified by quasi-stoichiometric (13) C-CO2 release. The metabolic potential of the dominant member affiliated with the genus Desulfuromonas in the heavy DNA fraction was inferred using assembled scaffolds (designated TF genome, 4.40 Mbp with 58.8 GC mol%), which were obtained by Illumina sequencing. The gene clusters with peripheral pathways for toluene and benzoate conversion possessed the features of strict and facultative anaerobes. In addition to the class II-type benzoyl-CoA reductase (Bam) of strict anaerobes, the class I-type (Bcr) of facultative anaerobes was encoded. Genes related to the utilization of various anaerobic electron acceptors, including iron, nitrate (to ammonia), sulfur and fumarate, were identified. Furthermore, genes encoding terminal oxidases (caa3 , cbb3 and bd) and a diverse array of genes for oxidative stress responses were detected in the TF genome. This metabolic versatility may be an adaptation to the fluctuating availability of electron acceptors and donors in tidal flats.
    Environmental Microbiology 09/2013; · 6.24 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The potential of hydrocarbon biodegradation in marine sediments was determined through the detection of a functional biomarker, the bssA gene coding for benzylsuccinate synthase, the key enzyme of anaerobic toluene degradation. Eight bssA clone libraries (409 sequences) were constructed from polluted sediments affected by the Prestige's oil spill in the Atlantic Islands' National Park, and hydrocarbon amended sediment microcosms in Mallorca. The amplified products and database-derived bssA-like sequences grouped into four major clusters as determined by phylogenetic reconstruction, principal coordinate analysis (PCoA) and a subfamily prediction tool. In addition to the classical bssA sequences that were targeted, we were able to detect sequences homologous to naphthylmethylsuccinate synthase gene (nmsA) and alkylsuccinate synthase gene (assA), the bssA homologues for anaerobic 2-methylnaphthalene and alkane degradation, respectively. The detection of bssA-like variants was determined by the persistence and level of pollution in the marine samples. The observed gene diversity was lower in the Mallorca sediments, which were dominated by assA-like sequences. In contrast, the Atlantic Islands samples, which were highly contaminated with a methylnaphthalene-rich crude oil showed a high proportion of nmsA-like sequences. Some of the detected genes were phylogenetically related to Deltaproteobacteria communities, previously described as the predominant hydrocarbon degraders at these sites. Differences between all detected bssA-like genes described to date indicate separation between marine and terrestrial sequences, and further subgrouping according to taxonomic affiliation. Global analysis suggested that bssA-homologues appeared to cluster according to substrate-specificity. We observed undetected divergent gene lineages of bssA homologues, which evidence the existence of new degrader groups in these environments.
    Applied and Environmental Microbiology 04/2013; · 3.95 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The dumping of dredged sediments represents a major stressor for coastal ecosystems. The impact on the ecosystem function is determined by its complexity not easy to assess. In the present study, we evaluated the potential of bacterial community analyses to act as ecological indicators in environmental monitoring programmes. We investigated the functional structure of bacterial communities, applying functional gene arrays (GeoChip4.2). The relationship between functional genes and environmental factors was analysed using distance-based multivariate multiple regression. Apparently, both the function and structure of the bacterial communities are impacted by dumping activities. The bacterial community at the dumping centre displayed a significant reduction of its entire functional diversity compared with that found at a reference site. DDX compounds separated bacterial communities of the dumping site from those of un-impacted sites. Thus, bacterial community analyses show great potential as ecological indicators in environmental monitoring.
    Marine pollution bulletin 11/2013; · 2.63 Impact Factor

Full-text

View
70 Downloads
Available from
Jun 4, 2014