So if I were to soul trap all the Daedra in Coldharbour...

WhiteCoatSyndrome

I was filling Soul Gems at a Dolmen and got to wondering: what happens to all those Daedra I'm soul-trapping? During the Planemeld, trapped souls are being sent to Coldharbour and presumably this applies to trapped Daedra as well. Do they just hang out in Coldharbour until the gem yanks them back to fuel my weapon enchantment? Or being Daedra, are they trapped differently, like the Foolkiller Clan was? Could I, theoretically speaking and assuming there are a finite number of Daedra in Coldharbour, soul-trap the entire population and thus end the Planemeld?

Sizaansil

I'll give my two cents here and try to provide a good answer :
"It has long been understood that a Daedra, who lacks the Anuic animus known as the "soul," is not killed when its body is destroyed. A Daedra slain upon Mundus is merely "banished" back to its plane of origin, where its morphotype, or "vestige," gradually forms a new body, so that eventually the Daedra lives again. (This happens as well when a Daedra is slain in its native Oblivion.)"
from en.uesp.net/wiki/Lore:Chaotic_Creatia:_The_Azure_Plasm
What I understood from soul trapping is that only the animus/energy of a soul gets stored in the soul gem and gets used to charge your enchantment and such. The Vestige (or pattern) however gets sent back to Coldharbour where it is filled with Creatia to reform the daedra.
So - in my opinion - for each soul one would trap, a deadra would be recreated with Creatia. And I'm convinced that soul gems would run out before the Creatia of Coldharbour does ^^