Robert Siron

Publications (2)5.72 Total impact

• Article: Fate of a new silicone‐based oil‐treating agent and its effects on marine microbial communities

  Jaime Padrós, Émilien Pelletier, Robert Siron, Daniel Delille
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  ABSTRACT: A new silicone-based agent was developed to treat and recover oil slicks and various floating oily residues that are often observed in marinas and harbors. As part of its ecotoxicologic assessment, the fate of the treating agent alone or combined with crude oil, and the effects on natural microbial communities were studied in estuarine mesocosms (3.5 m3) over a 9-week period. The ability of the in situ formed silicone layer to trap an oil slick at the water surface was highlighted by a significative reduction in the volatilization, natural dispersion, and sedimentation of the treated oil. The treatment favored the dissolution of light aromatic hydrocarbons such as methyl-naphthalenes but these compounds were rapidly biodegraded in the water column. The agent alone, as well as the treated or untreated oil, had no effect on the biomass and photosynthetic ability of the phytoplankton community entrapped in the mesocosms. A significant stimulation of oil-degrading bacteria was noted in mesocosms containing treated and untreated oil slicks. On the basis of these results, we conclude that the use of a silicone-based treating agent could be an effective countermeasure to an oil spill, with neither deleterious effects to natural microbial communities nor to long-term biodegradation of the unrecovered oil residues.
  Environmental Toxicology and Chemistry 11/2009; 18(5):819 - 827. · 2.81 Impact Factor
• Article: Effect of dispersed oil on heterotrophic bacterial communities in cold marine waters

  Daniel Delille, Robert Siron
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  ABSTRACT: Mesocosm studies were conducted to evaluate the effect of dispersed oil on total and heterotrophic bacterial communities of under-ice seawater from the St. Lawrence Estuary. A regular survey of bacterial changes in the oil-contaminated seawater was performed during a two week period. The bacterial community structure was investigated by carrying out 27 morphological and biochemical tests on 168 isolated strains. The results show a detectable but transient response of the bacterial community to crude oil addition. While total bacterial counts were approximately constant during the experiment, dispersed oil induced an increase in heterotrophic bacterial microflora (from 104 to 105 bacteria ml-1 after two weeks of contamination). The dispersed oil appeared to have an inhibitory effect on some components of the bacterial community. A decrease of most probable number values was observed just after addition of crude oil in the most polluted tanks and one day later in the less polluted tank. However, except for the most polluted tank, this adverse effect disappeared rapidly. While the dispersed oil induced a total disappearance of some components of the bacterial community in the most polluted tank, the structure of the bacterial community in the less polluted tank appeared relatively unchanged after 14 days of contamination.
  Microbial Ecology 04/1993; 25(3):263-273. · 2.91 Impact Factor