The on-going evolution of the critical zone, with respect to soils fertility and coupled ecohydrological processes, weathering and erosion rate, recharge processes and water provenance, flow paths, geochemical reactions, transit times is an issue of attention of the scientific community relative to societal expectations and environmental issues. All these are crucial factors in order to estimate the vulnerability and the recovery-time of the critical zone to assess soil erosion rates, to plan the sustainable use of water resources, and to protect ecohydrological systems under climate or land use change. To be meaningful they must be set in the context of the wider critical zone where most of the ecosystem services are provided. This session focuses on the advancing proxies that may address pressing interdisciplinary scientific questions concerning geological, physical, chemical, and biological processes and their couplings that may govern critical zone system dynamics, including sources, dynamics and chemistry of water, models to quantify external influences like human activities or erosion, weathering rate and water transfer in the frame of global change.