tell me
07.10.2008, 9 am, MedILS, large lecture hall
The phenomenon referred as «mucilage of Northern Adriatic» has been observed infrequently over the past three centuries but more recently its intensity and frequency of occurrence has increased dramatically. The phenomenon manifests itself in rapid production of enormous amounts of gelatinous matter in the water column and covering the sea surface at a scale observable from the satellite. The mucilage phenomenon has attracted attention of many scientists worldwide and research is performed by oceanographers, biologists and chemists. Current views leave no doubt on phytosynthetic production of long chain polysaccharide molecules by unicellular marine algae, as a proximal source constituting the gel network, but the basic mechanism of mucilage events is still not understood.
Studies of supramolecular organization of organic molecules in seawater into vesicles and microgels have revealed that the macroscopic phenomena, such as mucilage events are governed by biological and abiotic transformations at the micro- and nano- scales.
Discovery of AFM (Atomic Force Microscopy) has made possible the masurements of atomic forces for imaging living and non-living organic structures at molecular and sub-molecular resolution under ambient conditions.
I shall describe here how we applied AFM imaging to reveal the process of marine gel formation at the nanoscale, starting from extracellular production of polysaccharide chains by a living diatom cell, to gradual and multiple entanglement of polysaccharide molecules into the polysaccharide gel networks which reached macroscopic dimensions during the mucilage event.