https://doi.org/10.15255/KUI.2004.003
Published: Kem. Ind. 55 (12) (2006) 523–529
Paper reference number: KUI-03/2004
Paper type: Review
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Influence of Oil Contamination on the Sea Surface Microlayer

S. Frka Milosavljević

Abstract

Boundary layers between different environmental areas represent critical interfaces for biological, chemical and physical processes. The sea surface microlayer (SSM) as the uppermost 1–1000 μm forms the boundary layer interface between the atmosphere and ocean. It is now widely recognized that it plays a major role in the exchange of gases, material and energy. Also, it is a key interface for investigation of the fate and effects of airborne contaminants and particulate inputs into the sea, as well as for accumulation of dissolved pollutants. This thin layer is subject to many unique and dynamic, unbalanced processes such as wind stress, water transpiration, solar energy flux and atmospheric inputs. The SSM is also a unique ecosystem, an important habitat for marine neuston including fish eggs and larvć of many commercial species. It is rich in different natural and anthropogenic organic substances which are mostly surface active. The adsorbed organic substances form surfactant films and change physicochemical and optical properties of natural interface. The upper organic film of the SSM represents a sink for a range of pollutants, including chlorinated hydrocarbons, organotin compounds, petroleum hydrocarbons, polycyclic aromatic hydrocarbons and heavy metals. These pollutants can be enriched in the SSM by up to 104 times, relative to concentrations occurring in the underlying bulk water column. During the last few decades the marine oil pollution has become a matter of increasing international concern. Every year about 0.25 % of the world’s annual oil production ends up in the ocean affecting directly the SSM. Oil-polluted SSM is markedly toxic to fish eggs and larvć. Accumulation of organic pollutants from petroleum in the SSM has ecotoxicological impacts to the neustonic community including mortality, developmental abnormalities and depressed growth rates. These impacts produce dramatic effects on the marine food chain and reduce commercial catch of fish fishery recruitment in the coastal waters. Also, petroleum films can have a marked impact on exchange of heat, gases and particulate matter between the atmosphere and the ocean. It is a known fact that petroleum films due to the static effect retard evaporation, increase the temperature of the water surface film and decrease the ćration rate. Also, oil slicks are known to decrease turbulence at the interface, to damp wind-generated waves and to expert a strong effect on gas fluxes by hydrodynamic effects. Oil pollution of the SSM is extremely hazardous, especially to the closed and semi-closed costal marine environments, like the Adriatic Sea, where human influence may produce catastrophic effect on the whole marine ecosystem. A more systematic approach to research in physicochemical and biological processes of the SSM is needed for better understanding of this important environmental interface and its exact role in global distribution of human-borne contaminants.

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Keywords

sea surface microlayer, oil pollution, neuston, global changes, Adriatic Sea