The main aim of the project is to investigate quality and quantity of the seawater organic matter (lipids, acidic polysaccharides and polymeric organic matter containing N catalytic atoms) that is produced in the altering environment. Ecosystem changes that will be followed imply opposite nutritional regimes, oligotrophy and eutrophy, and temperature variations. Further on, this project aims to clarify how variations in the concentrations and forms of these organic substances are reflected in the availability and cycling of micronutrients metals of interest, being Fe, Co, Cu, Zn and Cd.