Environmental Influences on the Microbial Degradation of Exxon Valdez Oil on the Shorelines of Prince William Sound, Alaska

Abstract

Biodegradation was a major mechanism for removing oil resulting from the Exxon Valdez oil spill in Prince William Sound, Alaska. For three field seasons, we examined the hexadecane, phenanthrene, and naphthalene mineralization potentials of hydrocarbon-degrading microorganisms and the accompanying hydrocarbon concentrations from intertidal and shallow subtidal sediments. We found that mineralization potentials were not directly dependent on sediment substrate concentrations, but environmental factors influenced the ability of microbial populations to mineralize polycyclic aromatic and aliphatic compounds. These factors included the intensity of physical mixing experienced, the treatments received, and the availability of alternative carbon sources. In 1989, when the Exxon Valdez oil was relatively unweathered and before shoreline treatment was begun, the mineralization potentials of aromatic hydrocarbons were high at many sites even in the presence of alkanes at higher concentrations. However, by 1990, mineralization potentials for alkanes were greater than those for aromatics at oiled sites exposed to terrestrial biowaxes or fatty acids from the bioremediation process. Therefore, our study shows that sediment chemistry data alone cannot predict the persistence of hydrocarbons following the Exxon Valdez oil spill and demonstrates the need for systematic ecosystem-level studies of the abiotic and biotic factors influencing biodegradation.

Bioaugmentation and biostimulation strategies to improve the effectiveness of bioremediation processes

“…For instance, it was observed that factors including the intensity of physical mixing, the pre treatments (for example shore washing, manual removal, manual raking, bioremediation using biostimulation agents, mechanical tilling, mechanical relocation), and the availability of alternative carbon sources influenced the mineralization potential of the microbes after the Exxon Valdez oil spill (Sugai et al 1997). Another parameter that has a considerable effect on biodegradation is temperature, due to its effect on the viscosity, water solubility and chemical composition of the oil.…”

Crude oil bioremediation in sub-Antarctic intertidal sediments: chemistry and toxicity of oiled residues

“…The presence of HDB community in a remote location not previously exposed to fossil hydrocarbons is associated to the presence of biowaxes derived from vascular plants and other terrestrial carbon sources. The coincidence between high C18 mineralisation rate and the presence of high concentrations of C25+C27+C29+C31 alkanes in some reference and oiled bays of the Prince William Sound (60 30 0 N; 147 05 0 W) suggested that terrestrial biowaxes pre-conditioned the microbial populations for an efficient degradation of oil-derived alkanes (Sugai et al, 1997). A recent work conducted in Terre Adelie (Delille, Basse`res, & Dessommes, 1997) showed a significant response of the Antarctic sea-ice HDB community to the addition of oil and fertilizers to newly formed seaice.…”

Bioremediation of Oil on Shoreline Environments: Development of Techniques and Guidelines

“…The intricacy of interactions shown to influence the success of bioremediation in this study is not unique. Within the sediments of Prince William Sound, Alaska [70], the ability of the indigenous microbial population to mineralize hexadecane, phenanthrene, and naphthalene, has been shown to be influenced by the intensity of physical mixing, the method of bioremediation agent application, and the availability of alternative carbon sources. The efficacy of specific bioremediation formulations may be influenced by environmental conditions.…”