Sorption of organic matter on clay minerals in aquatic system and influence on sedimentary organic preservation. An example of lacustrine environment (Lac Pavin, France)

Abstract : Sorption of organic molecules on clay surfaces in aquatic environment influence organic sedimentation fluxes. It is well known that mineral sorption affects transport of natural organic matter to bottom water and to sediments. These physical and chemical interactions produce a flocculation of organo-mineral complexes and then increase weight of sedimentary fractions. The resulting sedimentation rate reduces risks of bacterial recycling and/or oxidation. Other studies revealed that sorption also influences the fate of organic matters in sediments ([1]). Direct contacts between clay minerals and organic molecules allow creation of organo-mineral assemblages in sediments, and influence organic molecules availability to benthic fauna and bacteria ([2]). Many studies concluded that mineral sorption and chemical linkage created can be considered as one of preservation mechanism, leading incorporation of organic matter in sediments.