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Oil stranded by the 1989 Exxon Valdez spill has persisted in subsurface sediments of exposed shores for 16 years. With annualized loss rates declining from approximately 68% yr(-1) prior to 1992 to approximately 4% yr(-1) after 2001, weathering processes are retarded in both sediments and residual emulsified oil ("oil mousse"), and retention of toxic polycyclic aromatic hydrocarbons is prolonged. The n-alkanes, typically very readily oxidized by microbes, instead remain abundant in many stranded emulsified oil samplesfrom the Gulf of Alaska. They are less abundant in Prince William Sound samples, where stranded oil was less viscous. Our results indicate that, at some locations, remaining subsurface oil may persist for decades with little change.

Extruded brine, generated during sea ice formation in nearshore arctic waters, will sink to the bottom and can form a stable bottom boundary layer. This layer can persist for periods of up to 4-6 months. Limited quantities of dissolved aromatic hydrocarbons resulting from a spill of crude oil or refined petroleum distillate products during periods of ice growth can be transported as conservative components to the benthos with sinking brine. Once incorporated into the stable bottom boundary layer, these aromatic components are no longer subject to loss by evaporative processes, and they only can be diluted by ultimately mixing with uncontaminated water masses, a process that proceeds slowly throughout the ice-covered period. This mechanism for the transport of dissolved hydrocarbons has been demonstrated through a laboratory test-tank simulation and a chemical/physical oceanographic field program conducted in the Chukchi Sea near Pt. Frankline, AK (March 1985). The results are pertinent to shallow nearshore oil and gas exploration, development, production, and transportation activities in high latitude marine systems.

Photooxidation of petroleum in the marine environment causes changes in the oil and enhanced dissolution of its oxidized products. In this paper several photooxidation studies of crude petroleum are reviewed. Types of petroleum, light sources, identified products, and the presence or absence of sensitizers are given. 39 references, 3 figures, 2 tables.