deep water cycle
... that recent research has shown the presence of a deep water cycle all the way down through the Earth's lower mantle?
... that recent research has shown the presence of a <b id="mwBXQ"><a href="./Deep_water_cycle" id="mwBXU" rel="mw:WikiLink" title="Deep water cycle">deep water cycle</a></b> all the way down through the Earth's lower mantle?