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: 6.2). 03/2011; 13(6):1488-99. DOI: 10.1111/j.1462-2920.2011.02451.x
Source: PubMed


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.

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Available from: Ana Suarez-Suarez
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    • "Katayama et al. (2003) maintaining sediments in a tidal flat simulator, with a wave generator and a tide control device, identified oil-susceptible bacteria as bio-indicator of pollution by combining culture-dependent and molecular approaches. Suárez-Suárez et al. (2011) installed mesocosms in situ to assess the role of sulfate reducing bacteria in the degradation of Prestige oil. Similarly, Coulon et al. (2012), maintaining intact cores of coastal mudflat sediments in mesocosms under tidal cycles without renewing water, observed the development of phototrophic biofilm playing a crucial role in hydrocarbon degradation. "
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    ABSTRACT: Coastal marine sediments, where important biological processes take place, supply essential ecosystem services. By their location, such ecosystems are particularly exposed to human activities as evidenced by the recent Deepwater Horizon disaster. This catastrophe revealed the importance to better understand the microbial processes involved on hydrocarbon degradation in marine sediments raising strong interests of the scientific community. During the last decade, several studies have shown the key role played by microorganisms in determining the fate of hydrocarbons in oil-polluted sediments but only few have taken into consideration the whole sediment’s complexity. Marine coastal sediment ecosystems are characterized by remarkable heterogeneity, owning high biodiversity and are subjected to fluctuations in environmental conditions, especially to important oxygen oscillations due to tides. Thus, for understanding the fate of hydrocarbons in such environments, it is crucial to study microbial activities, taking into account sediment characteristics, physical-chemical factors (electron acceptors, temperature), nutrients, co-metabolites availability as well as sediment’s reworking due to bioturbation activities. Key information could be collected from in situ studies, which provide an overview of microbial processes, but it is difficult to integrate all parameters involved. Microcosm experiments allow to dissect in-depth some mechanisms involved in hydrocarbon degradation but exclude environmental complexity. To overcome these lacks, strategies have been developed, by creating experiments as close as possible to environmental conditions, for studying natural microbial communities subjected to oil pollution. We present here a review of these approaches, their results and limitation, as well as the promising future of applying ‘omics’ approaches to characterize in-depth microbial communities and metabolic networks involved in hydrocarbon degradation.
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    • "We hypothesized that shifts in these communities might be related to alterations in the degradation of pollutants, which are oxidized during the processes of sulphate reduction (Suarez-Suarez et al., 2011). Based on this hypothesis, mangroves with distinct interventions may show distinct groups involved in sulphur cycling. "
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    • "They also appear to be relatively more abundant in unvegetated environments such as port settings (Cleary et al., 2012a). Recent studies provide evidence that marine sediment contamination with oil hydrocarbons can increase the dominance of Desulfobacterales and promote SRB metabolism (Acosta-González et al., 2012; Suárez-Suárez et al., 2011). Chronic marine environmental contamination with fossil fuel, due to intense port activity may have favored the growth of anaerobic SRB biodegrading guilds in port areas. "
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