We propose to measure intracellular and transmembrane water dynamics in microbes at extremely high pressure. We will study S. oneidenisis that provides a model for extremophile behaviour and that we have previously adapted to survive into the GigaPascal pressure range. QENS experiments on H- vs D-labelled cells suspended in H/D media using specially developed HP devices at IN5 or IN6 will allow us to observe intracellular water mobility under extremely high pressure for the first time, and examine pressure effects on water transport through transmembrane Aquaporin channels. The results will give a unique view on microbial functioning under extreme conditions.