A levy on using coral reef (5)
I believe the answer is:
atoll
'coral reef' is the definition.
(atoll is a kind of coral reef)
'a levy on' is the wordplay.
'levy' becomes 'toll' (I've seen this in another clue).
'on' says to put letters next to each other.
'a'+'toll'='ATOLL'
'using' is the link.
(Other definitions for atoll that I've seen before include "String of islands" , "Circular coral reef" , "land threatened by rising sea levels" , "Bikini for one" , "Coral circle" .)