The Mariana Trench is one of the most famous extreme environment on our planet. Salinity is around 35 g salts per one kg of water at temperatures ranging from 274 K to 277 K , at a pressure of 1.1 kbar. Previous DINS measurements on dilute acid or basic water solutions have shown an extended effect of the ions on the surrounding water, suggesting that proton transport mechanisms in water may be an example of coherent transport. Our proposed experiment aims at characterizing the proton quantum state of water in the Mariana Trench ¿Challenger Deep¿ conditions, where the effects of ions is expected to induce large scale perturbations in the neutron Compton profile with respect to the bulk. Quantitative comparison with theoretical calculation of the proton mean kinetic energy of water in the vicinity of dissolved ions will be also carried out.