The hidden water reservoir – an engine for a dynamic and habitable planet

Earth´s habitability and climate largely depend on water. All reactions occurring in living cells and all living ecosystems require water.

Even more, trace amounts of water change the elastic properties and density of Earth´s crust, enhance melting and chemical transfer. Indirectly, water controls earthquakes, volcanic eruptions, gas emissions and hydrothermal ore deposits. Through subduction water is transported from the surface to great depths and volcanism releases it into the atmosphere.

Behind this global water cycle, an estimated equivalent of several oceans worth of water is hidden in Earth´s interior, in nominally anhydrous minerals.

It is critical to accurately estimate the total water on Earth and to understand which affinities allow its recycling and deep storage.This project sets to provide a first comprehensive model for the inner water cycle by studying three key settings: fresh basalts; crustal eclogites; exhumed mantle eclogites.

This study will (i) quantify water under various structural configurations; (ii) define its behaviour linked to key isotope tracers for crustal recycling (δ7Li, δ18O).This four-year project will benefit from the researcher´s expertise in petrology, required isotope systematics and analytical techniques, as well as a sample set already in her possession.

This novel, multi-analytical project will inform models on water distribution in Earth´s history and open up a new research avenue for water and life on other planets.