کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4541276 1326716 2009 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Characterization and seasonal variations of surface active substances in the natural sea surface micro-layers of the coastal Middle Adriatic stations
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Characterization and seasonal variations of surface active substances in the natural sea surface micro-layers of the coastal Middle Adriatic stations
چکیده انگلیسی
Surface micro-layer (ML) samples were collected in different seasons over a long time period in the coastal area of the Middle Adriatic Sea including the seawater Rogoznica lake location and the semi-enclosed estuarine Martinska station. Natural surface micro-layers were studied as original samples and as ex-situ reconstructed films after previous extraction by organic solvents of different polarities (n-hexane and dichloromethane). Using alternating current (AC) voltammetry (out-of-phase mode) the concentration of surface active substances (SAS) in original ML of both locations was determined, and the enrichment factor (EF) in the ML was related to the underlayer water (ULW) samples collected at 0.5 m depth. Seasonal variability of SAS concentrations of the ML was observed at both locations. The ex-situ films were studied using a modified AC voltammetry method (out-of-phase mode) transferring an organic extract of natural micro-layers spread onto electrolyte from the air-water interface to the mercury electrode surface. The comparison of adsorption characteristics for model lipids of different polarities and those of transferred ex-situ reconstructed films has revealed that different types of lipid material were present in each ex-situ film of the same micro-layer. Additional characterization of the surface active material of natural MLs was carried out by AC voltammetry (in-phase mode) using cathodic reduction of cadmium ions as an indicator of permeability of different films adsorbed at the mercury electrode. The SAS of ML of both investigated locations induced an inhibition effect to the reduction of cadmium ions. Seasonal variations of inhibition have also been noticed. The electrochemical study contributed to the physicochemical characterization of the surface active matter of the surface micro-layer with the emphasis to the role of lipids which, although they represent a minor fraction of the total micro-layer organic material, contribute considerably to the micro-layer formation and stabilization at the air-water interface.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Estuarine, Coastal and Shelf Science - Volume 85, Issue 4, 15 December 2009, Pages 555-564
نویسندگان
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