Fossiles moléculaires d'intérêt microbiologique, pétrolier, agronomique et environnemental

Molecular fossils are organic substances occurring in soils, sediments, coals and crude oils. The study of these structurally specific fossils has generated applications among several scientific fields. For instance, the discovery of fossil hopanes in petroleum in 1970 has unexpectedly led to the identification of novel bacterial substances, hopanols, in 1976 ! Here, a handful of such ≪ orphan ≫ fossils await the discovery of their ≪ parents ≫ in modern biological organisms. Further, molecular fossils have been widely used to decrypt the biogeochemical processes ruling the degradation and the maturation of sedimentary organic matter with increasing burial. The findings have proved particularly efficient to locate new petroleum deposits. More recently, molecular and isotopic investigations of soils have revealed novel pathways of transformations of humic substances. To this end, a method has been set up to measure the long-term turnover of individual organic substances in soil. Last, molecular fossils are now used as tools to authenticate polluted samples and to remediate petroleum-polluted media such as soils, plants, atmosphere, recent sediments and food.