engleski

Natural surfactants of the sea surface films from the coastal Middle Adriatic area

The sea surface microlayer (SML) as a top layer of the ocean surface represents a natural interface between the atmosphere and the ocean. Although < 1 mm in thickness, the SML is central to a range of global dynamic exchange processes between the atmosphere and the aquatic environments where striking variety of biogeochemical and photochemical interactions and feedbacks occur. A large fraction of the SML organic matter has a particularly strong interfacial affinity. Due to their molecular structures, such surface active substances (SAS) are adsorbed at the air-water interface forming natural surface films which change the physicochemical properties of the interface and influence the air-sea exchange processes. A new perspective to the physicochemical characterization of the SML properties regarding the composition and the structure of dominant surface active material has been recently studied on the SMLs from the coastal Middle Adriatic locations, including the seawater Rogoznica Lake and Martinska station situated at the Krka river estuary. Our work has shown that chemical composition and distribution of the SML surfactants are influenced by the presence of certain end-member material of hydrophobic, lipid-like surfactants which strongly influenced the surface properties of natural air-sea interface. Due to their extremely high surface affinity, the presence of lipids at the interface is the result of their competitive adsorption and segregation from other macromolecular constituents which is closely related to the periods of primary production.

sea surface microlayer; surface active substances; surface pressure-area isotherms; Brewster angle microscopy

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