"This interdisciplinary proposal aims to make important contributions in the field of microbes-mineral interactions using as model system the boring process of endolithic cyanobacteria. Cyanobacteria are photosynthetic bacteria which count among the most common, widespread and environmentally significant agents of bio-erosion, boring microscopic galleries as they grow within carbonate substrates. The mechanisms by which they achieve this against chemical equilibrium are poorly known. This project objective is to better understand mechanisms involved in cyanobacteria boring activity, detail, its phylogenetic distribution and to characterize the mineral and geochemical signatures of this process, so as to be able to apply it in the interpretation of paleobiological records.This will be achieved by studying laboratory cultures of cyanobacteria, performing boring assays in various substrates, and monitoring the boring activity. Diverse tools from molecular biology, microbiology and geochemistry will be used including confocal laser scanning microscopy, electron microscopy and secondary ion mass spectroscopy. That all together will allow in-situ survey of intracellular and extracellular chemistry variations, the identification of molecular bases of the process as well as the nature and distribution of mineral phases and organic. This will help to refine microbial and mineralogical models for the mechanisms involved, and to assess the quantitative importance of boring cyanobacteria in present and past ecosystem.My goal with this proposal is to establish a truly interdisciplinary expertise in the study of endolithic cyanobacteria by joining the skills and tools of the Garcia-Pichel lab (ASU-USA) and Biogéosciences lab (uB-France). This project will be a unique opportunity to become an accomplished researcher in geomicrobiology able to collaborate with people from both research fields and to apply this unique dual toolbox to the development of my own project in the future."