VESICLE TO GEL PHASE TRANSITION IN A NATURAL ENVIRONMENT

Vesna Svetlicic

Ruđer Bošković Institute, Center for Marine and Environmental Research

Abiotic transformation of organic matter in the aquatic environments such as seawater depends more on the interfacial properties of organic matter than on its chemical composition. These properties, purely understood so far, can be measured by a direct application of the electrochemical adhesion sensor which we have developed based on our fundamental studies in the fields of surface electrochemistry and biophysics. EXAMPLE The macroscopic gel phase (mucilage) appears episodically in the northern Adriatic Sea covering tens of square kilometers of seasurface. The hallmark of the mucilage phenomenon is the rapid (1-100 h) appearance of enormous amounts of gelatinous organic matter. No biological process could reasonably be identified that is capable of producing organic matter at such rapid rate. Current views leave no doubt on phytoplankton production as a proximal source of polymers constituting the gel network, but the mechanism leading to its rapid production remains unknown. We propose the biophysical scenario of mucilage event featuring self-organization of biopolymers into microparticles, "marine vesicles" that under specific conditions transform to giant-gel by a phase transition process. We introduced electrochemical sensing of marine microparticles and Atomic Force Microscopy (AFM) to image supramolecular organization of marine gel network.

Email: svetlicic@irb.hr

Address: Rudjer Boskovic Institute, Bijenicka 54, 10000 Zagreb, Croatia