Complex interactions between surface water chemistry, phytoplankton, atmospheric chemistry, and climate are among the most challenging global climate issues today, and should become even more pronounced in future climate scenarios. With a holistic, multidisciplinary approach, the BiREADI is designed to assess the impact of atmospheric deposition (AD) on complex biochemical responses of oligotrophic systems, considering the importance of promotion and inhibition effects on phytoplankton, and the consequent altering of the surface water chemistry, including the sea surface microlayer at the air-water interface. To achieve the main project goals, a phased approach is proposed: Phase I - to evaluate concentrations, sources and deposition fluxes of atmospheric constituents, and to get insight into the nature of enrichments of macro-nutrients, trace metals and organic pollutants within the sea surface layers; Phase II - to assess the impact of ambient AD from diverse sources on the physiology and biomass of the natural plankton population, and consequently on the chemistry of the sea surface layers; Phase III - to get insight into the mechanisms by which AD affects marine phytoplankton, but also to assess the toxic effects of atmospheric pollutants that can interact synergistically on various levels of biological organisation in aquatic systems; Phase IV - to better understand the nature of biogenic OM variabilities within the aqueous surface layers affected by AD inputs with the consequences on the surface film formation and properties. The BiREADI will make a significant progress in the fundamental understanding of the linkage between AD inputs and complex surface ocean biochemical responses by a state-of-the-art laboratory and modelling studies, and by comprehensive field work including the mesocosm experiment at the Middle Adriatic - an extremely oligotrophic water zone and the «hotspot» area to study the biochemical effects of AD to the Adriatic Sea.