Linked with the changing tide (4)
I believe the answer is:
tied
'linked' is the definition.
(tying is a kind of linking)
'changing tide' is the wordplay.
'changing' indicates an anagram.
'tide' with letters rearranged gives 'TIED'.
'with the' acts as a link.
(Other definitions for tied that I've seen before include "Bound; placed equal" , "Roped into diet" , "eg Scored 1-1" , "With an equal score" , "In no-win situation" .)