these are Beautiful answers! thank you! i was only asking because of my wondering "well, where the heck the Ekkaia go after the bending of Arda??" then i began to kick in my metaphorical thought, as well as a bit of knowledge about the
iconic properties of water, its Chaotic associations, plus talk in the HoME about "special ships" that only Ulmo had to travel in the "waveless dark Outer Oceans" or something to that effect...as well as the whole "Arda floating like a ship in the dark waveless waters of Vai" deal.
if only Ulmo can travel there, and there were no ocean life in it, and it was so dark as to be pitch black, then maybe this was the metaphor for Outer Space...? and maybe Ulmo is a powerful Spirit of Outer Space who chose water (which the thinking is that it came to Earth billions of years ago on
ice comets from Space) as his way to communicate with Earth or relate to the Children on terms that they could understand?