Vampire maybe in river causes argument (6)
I believe the answer is:
debate
'argument' is the definition.
(I know that argument can be written as debate)
'vampire maybe in river' is the wordplay.
I cannot really see how this works, but
'vampire' could be 'bat' (I've seen this in another clue) and 'bat' is found in the answer.
'river' could be 'dee' (River Dee) and 'dee' is present in the remaining letters.
No letters remain.
This explanation may well be incorrect...
'causes' acts as a link.
Can you help me to learn more?
(Other definitions for debate that I've seen before include "Argue a point" , "Discuss through argument" , "A public discussion about a topic" , "Discuss formally" , "Discussion with arguments for and against" .)