ROLE OF EXTRACELLULAR POLYMERIC SUBSTANCES (EPS) IN MINERAL PRECIPITATION IN THE OCEAN: IMPLICATION FOR BIOGEOCHEMICAL CYCLES.

THIS PROJECT AIMS A MULTIDISCIPLINARY RESEARCH OF THE ROLE THAT EXTRACELLULAR POLYMERIC SUBSTANCES (EPS) PLAY IN MINERAL PRECIPITATION IN THE OCEANS AND IN TURN IN BIOGEOCHEMICAL CYCLES NOT FULLY UNDERSTOOD. MECHANISMS FOR MINERAL PRECIPITATION IN THE OCEAN ARE NOT KNOWN YET FOR CERTAIN MINERALS. AS EXAMPLE, THE BARITE PRECIPITATION AND THE BIOGEOCHEMICAL CYCLE OF BARIUM, OF KEY IMPORTANCE IN GLOBAL CHANGE RESEARCH BECAUSE IT IS CLOSELY RELATED TO THE CARBON CYCLE, ARE VERY POORLY UNDERSTOOD. THIS MINERAL, BARITE, IS A RELIABLE PRODUCTIVITY PROXY SINCE BA DISTRIBUTION IN THE OCEAN WATER COLUMN AND SEDIMENTS MIRRORS CARBON FLUXES. HOWEVER, DESPITE BA PROXIES HAVE USED FOR DECADES, BA PRECIPITATION IN UNDERSATURATED SEAWATER IS NOT YET KNOWN. OUR RECENT FINDINGS DEMONSTRATE THAT EPS PLAY A MAJOR ROLE, WHICH HAS OPENED AN EXCITING FIELD OF RESEARCH IN ORDER TO EXPLORE THE ROLE OF EPS IN THE SEDIMENTARY RECORD. SIMILARLY OTHER MINERALS HAVE BEEN TRADITIONALLY ATTRIBUTED INORGANIC PRECIPITATION AS IS THE CASE FOR CLAYS. HOWEVER, EPS MAY PLAY AN ESSENTIAL ROLE Y CLAY PRECIPITATION, WHICH IN TURN HAS MAJOR IMPORTANCE IN OIL RESERVOIRS WHERE CLAY FORMATION MAY SIGNIFICANTLY ALTER ORIGINAL POROSITY. THUS, WE PROPOSE TO INVESTIGATE THE ROLE OF EPS IN MINERAL PRECIPITATION AND ELEMENT ABSORPTION IN THE OCEAN AS WELL AS IN BIOGEOCHEMICAL CYCLES. THE RESEARCH TEAM IS HIGHLY MULTIDISCIPLINARY INVOLVING EXPERTISE ON MICROBIOLOGY, MINERALOGY, GEOCHEMISTRY, CRYSTALLOGRAPHY, SEDIMENTOLOGY AND GEOMICROBIOLOGY, AS THE PROPOSED RESEARCH REQUIRES A MULTIPROXY APPROACH.